Àíãëèéñêèå ìàòåðèàëû
|
| Àâòîðû |
Íàçâàíèå ñòàòüè |
Îïèñàíèå |
Ðåéòèíã |
| Marco Mattavelli and Giorgio Zoia |
Vector-Tracing Algorithms for Motion Estimation in Large Search Windows |
Abstract—Despite the several efforts aimed at reducing the
complexity, block-based motion estimation remains the most
computationally demanding stage of video compression algorithms.
This is particularly evident when sequences contain large
displacements; very large search windows are needed to achieve
high-quality coding when such critical conditions occur. This
paper presents a new block-motion-estimation algorithm based
on the systematic application of the tracing of motion trajectories
on a modified genetic search heuristic. The described technique is
able to provide motion estimates in very large search windows with
optimal coding results. The complexity-reduction factor ranges
up to more than two orders of magnitude. The technique can be
applied to any macroblock-based video compression standard and
to any group of picture structure.
RAR 268 êáàéò
|
?
|
| Ertem Tuncel, and Levent Onural |
Utilization of the Recursive Shortest Spanning Tree Algorithm for Video-Object Segmentation by 2-D Affine Motion Modeling |
Abstract—A novel video-object segmentation algorithm is
proposed, which takes the previously estimated 2-D dense motion
vector field as input and uses the generalized recursive shortest
spanning tree method to approximate each component of the
motion vector field as a piecewise planar function. The algorithm
is successful in capturing 3-D planar objects in the scene correctly,
with acceptable accuracy at the boundaries. The proposed algorithm
is fast and requires no initial guess about the segmentation
mask. Moreover, it is a hierarchical scheme which gives finest
to coarsest segmentation results. The only external parameter
needed by the algorithm is the number of segmented regions that
essentially control the level at which the coarseness the algorithm
would stop. The proposed algorithm improves the “analysis
model” developed in the European COST211 framework.
RAR 467 êáàéò
|
?
|
| Kevin Hilman, Hyun Wook Park, and Yongmin Kim,Fellow, EEE |
Using Motion-Compensated Frame-Rate Conversion for the Correction of 3 : 2 Pulldown Artifacts in Video Sequences |
RAR 283 êáàéò
|
?
|
| Theophilos Papadimitriou, Konstantinos I. Diamantaras, Michael G. Strintzis, and Manos Roumeliotis |
Robust Estimation of Rigid-Body 3-D Motion Parameters Based on Point Correspondences |
Abstract—Currently, the most popular method of converting 24
frames per second (fps) film to 60 fields/s video is to repeat each
odd-numbered frame for 3 fields and each even-numbered frame
for 2 fields. This method is known as 3 : 2 pulldown and is an easy
and inexpensive way to perform 24 fps to 60 fields/s frame-rate conversion.
However, the 3 : 2 pulldown introduces artifacts, which are
especially visible when viewing on progressive displays and during
slow-motion playback. We have developed a motion-compensated
frame-rate conversion algorithm to reduce the 3 : 2 pulldown artifacts.
By using frame-rate conversion with interpolation instead
of field repetition, mean square error and blocking artifacts are
reduced significantly. The techniques developed here can also be
applied to the general frame-rate conversion problem.
RAR 300 êáàéò
|
?
|
| Dimitrios Tzovaras, Nikiforos Ploskas, and Michael G. Strintzis |
Rigid 3-D Motion Estimation Using Neural Networks and Initially Estimated 2-D Motion Data |
Abstract—This paper extends a known efficient technique for
rigid three–dimensional (3-D) motion estimation so as to make
it applicable to motion-estimation problems occuring in image
sequence coding applications. The known technique estimates 3-D
motion using previously evaluated 3-D correspondence. However,
in image sequence coding applications, 3-D correspondence is
unknown and usually only two-dimensional (2-D) motion vectors
are initially available. The novel neural network (NN) introduced
in this paper uses initially estimated 2-D motion vectors to estimate
3-D rigid motion, and is therefore suitable for image sequence
coding applications. Moreover, it is shown that the NN introduced
in this paper performs extremely well even in cases where 3-D
correspondence is known with accuracy. Experimental results are
presented for the evaluation of the proposed scheme.
RAR 305 êáàéò
|
?
|
| Renxiang Li, Bing Zeng, and Ming L. Liou |
Reliable Motion Detection/Compensation for Interlaced Sequences and Its
Applications to Deinterlacing |
Abstract—In this letter, we present a new method for the motion
detection/compensation between opposite parity fields in interlaced
video sequences. We introduce a phase-correction filter,
which is applied to one type (even or odd) of fields before motion
detection/compensation. By means of this phase-correction filter,
the motion-compensated PSNR has been improved by more than
2 dB, on average. We also present a new deinterlacing algorithm
based on the newly developed motion detection/compensation. This
algorithm requires storing one field only, and the phase-corrected
field is used for both motion detection/compensation and intrafield
deinterlacing, thus making the proposed algorithm computationally
very efficient. Excellent deinterlacing results have been obtained.
RAR 176 êáàéò
|
?
|
| Yap-Peng Tan, Drew D. Saur, Sanjeev R. Kulkarni, and Peter J. Ramadge, Fellow |
Rapid Estimation of Camera Motion from Compressed Video with Application to Video Annotation |
Abstract—As digital video becomes more pervasive, efficient
ways of searching and annotating video according to content
will be increasingly important. Such tasks arise, for example,
in the management of digital video libraries for content-based
retrieval and browsing. In this paper, we develop tools based on
camera motion for analyzing and annotating a class of structured
video using the low-level information available directly from
MPEG-compressed video. In particular, we show that in certain
structured settings, it is possible to obtain reliable estimates
of camera motion by directly processing data easily obtained
from the MPEG format. Working directly with the compressed
video greatly reduces the processing time and enhances storage
efficiency. As an illustration of this idea, we have developed a
simple basketball annotation system which combines the low-level
information extracted from an MPEG stream with the prior
knowledge of basketball structure to provide high-level content
analysis, annotation, and browsing for events such as wide-angle
and close-up views, fast breaks, probable shots at the basket, etc.
The methods used in this example should also be useful in the
analysis of high-level content of structured video in other domains.
RAR 385 êáàéò
|
?
|
| Injong Rhee, Graham R. Martin, S. Muthukrishnan, and Roger A. Packwood |
Quadtree-Structured Variable-Size Block-Matching Motion Estimation with
Minimal Error |
Abstract—This paper reports two efficient quadtree-based algorithms
for variable-size block matching (VSBM) motion estimation.
The schemes allow the dimensions of blocks to adapt to local
activity within the image, and the total number of blocks in any
frame can be varied while still accurately representing true motion.
This permits adaptive bit allocation between the representation
of displacement and residual data, and also the variation of
the overall bit-rate on a frame-by-frame basis. The first algorithm
computes the optimal selection of variable-sized blocks to provide
the best-achievable prediction error under the fixed number of
blocks for a quadtree-based VSBM technique. The algorithm employs
an efficient dynamic programming technique utilizing the
special structure of a quadtree. Although this algorithm is computationally
intensive, it does provide a yardstick by which the performance
of other more practical VSBM techniques can be measured.
The second algorithm adopts a heuristic way to select variable-
sized square blocks. It relies more on local motion information
than on global error optimization. Experiments suggest that
the effective use of local information contributes to minimizing the
overall error. The result is a more computationally efficient VSBM
technique than the optimal algorithm, but with a comparable prediction
error.
RAR 165 êáàéò
|
?
|
| Chung J. Kuo, Chia H. Yeh, and Souheil F. Odeh |
Polynomial Search Algorithms for Motion Estimation |
Abstract—This paper proposes a polynomial search (PS) algorithm
and architecture to solve the motion-estimation problem in
video coding. Simulation results show that the proposed method is
not only flexible, but also requires fewer computations to achieve
the same mean absolute error results (for QCIF and sub-QCIF
video) compared with the existing fast-search algorithms. Finally,
a VLSI architecture is also developed to efficiently implement the
PS algorithm.
RAR 125 êáàéò
|
?
|
| Prakash Ishwar and Pierre Moulin |
On Spatial Adaptation of Motion-Field Smoothness in Video Coding |
Abstract—Most motion-compensation methods dealt with in the
literature make strong assumptions about the smoothness of the
underlying motion field. For instance, block-matching algorithms
assume a blockwise-constant motion field and are adequate for
translational motion models; control-grid interpolation assumes a
blockwise bilinear motion field and captures zooming and warping
fairly well. Time-varying imagery, however, often contains both
types of motion (as well as others), and hence exhibits a high degree
of spatial variability of its motion-field smoothness properties.
We develop a simple method to spatially adapt the smoothness of
the motion field. The proposed method demonstrates substantial
improvements in video quality over a wide range of bit rates. To
this end, we introduce the notion of a motion field that is characterized
by a set of labels. The labels provide the flexibility to
adaptively switch between two different motion models locally. The
individual motion models have very different smoothness properties.
The switched framework for motion compensation performs
significantly better than each of its constituent motion models, in
terms of both visual quality and signal-to-noise ratio (0.3–0.7 dB
on the average). Finally, we develop an extension of this method
that enhances the overlapped block motion compensation scheme
by allowing spatial adaptation of the window function.
RAR 598 êáàéò
|
?
|
| Chok-Kwan Cheung and Lai-Man Po |
Normalized Partial Distortion Search Algorithm for Block Motion Estimation |
Abstract—Many fast block-matching algorithms reduce computations
by limiting the number of checking points. They can
achieve high computation reduction, but often result in relatively
higher matching error compared with the full-search algorithm.
In this letter, a novel fast block-matching algorithm named normalized
partial distortion search is proposed. The proposed algorithm
reduces computations by using a halfway-stop technique in
the calculation of block distortion measure. In order to increase
the probability of early rejection of non-possible candidate motion
vectors, the proposed algorithm normalized the accumulated partial
distortion and the current minimum distortion before comparison.
Experimental results show that the proposed algorithm can
maintain its mean square error performance very close to the full
search algorithm while achieving an average computation reduction
of 12–13 times, with respect to the full-search algorithm.
RAR 123 êáàéò
|
?
|
| Xudong Song, Tihao Chiang, Xiaobing Lee, and Ya-Qin Zhang, Fellow |
New Fast Binary Pyramid Motion Estimation for MPEG2 and HDTV Encoding |
Abstract—A novel Fast Binary Pyramid Motion Estimation
(FBPME) algorithm is presented in this paper. The proposed
FBPME scheme is based on binary multiresolution layers, exclusive-
or (XOR) Boolean block matching, and a -scale tiling search
scheme. Each video frame is converted into a pyramid structure of
1 binary layers with resolution decimation, plus one integer
layer at the lowest resolution. At the lowest resolution layer, the
-scale tiling search is performed to select initial motion vector
candidates. Motion vector fields are gradually refined with the
XOR Boolean block-matching criterion and the -scale tiling
search schemes in higher binary layers.
FBPME performs several thousands times faster than the conventional
full-search block-matching scheme at the same PSNR
performance and visual quality. It also dramatically reduces the
bus bandwidth and on-chip memory requirement. Moreover, hardware
complexity is low due to its binary nature.
Fully functional software MPEG-2 MP@ML encoders and Advanced
Television Standard Committee High Definition Television
encoders based on the FBPME algorithm have been implemented.
FBPME Hardware architecture has been developed and is being
incorporated into single-chip MPEG encoders. A wide range of
video sequences at various resolutions has been tested. The proposed
algorithm is also applicable to other digital video compression
standards such as H.261, H.263, and MPEG4.
RAR 563 êáàéò
|
?
|
| Jorge Sastre, Antonio Ferreras, and José Félix Hernández-Gil |
Motion Vector Size-Compensation Based Method for Very Low Bit-Rate Video Coding |
Abstract—In this paper, a new method to achieve better
compression efficiency in low bit-rate video coding is proposed.
It is based on a global bit-rate reduction at a macroblock level,
optimizing the number of bits to code each macroblock as a whole
by means of motion vector and headers size compensation. The
selection of the best motion vector and different coding modes for
each block of the current picture will be made depending not only
on trying to choose the best prediction for the block, but also on
the number of bits to code the associate headers, introducing some
kind of penalization in the cost function. This method improves
efficiency on video compression for all qualities, but especially
for low-quality video coding, whose efficiency improvement can
reach 17%. Its implementation is simple, and compatible with
most video-compression standards (H.263, MPEG, etc.). Results
of the algorithm in a state-of-the-art H.263+ codec are presented,
and demonstrate that the efficiency enhancement is achieved with
minimal time-processing increase, and even decrease, in some
conditions.
RAR 440 êáàéò
|
?
|
| Oscal T.-C. Chen |
Motion Estimation Using a One-Dimensional Gradient Descent Search |
Abstract—This work presents a low-complexity high-performance
motion estimation method using a one-dimensional
(1-D) gradient descent search. The proposed method consists
of initial-point determination, initial-direction determination, a
gradient descent search using variable step sizes and conjugate
directions, and convergence checking. For each block, one of
the original and predictive points with the best block-matching
performance is the initial point where the predictive ones are
motion vectors of its neighboring four searched blocks. In addition,
the searching path is optimized by determining the initial
direction based on the vector from the original point to the
initial point. After determining the initial point and direction, the
gradient descent search using variable step sizes and conjugate
directions is performed until the searched point attains a better
performance than its neighboring points. Moreover, variable
step sizes for moving and slowly moving, or stationary blocks,
are well addressed to improve the convergence performance of a
gradient descent search. Simulation results demonstrate that our
method yields a superior performance in terms of computational
complexity and picture quality as compared to the three-step
search, 1-D full search, block-based gradient descent search, and
one-at-a-time search methods.
RAR 239 êáàéò
|
?
|
| Peter Eisert, Thomas Wiegand, and Bernd Girod, Fellow |
Model-Aided Coding: A New Approach to Incorporate Facial Animation into Motion-Compensated Video Coding |
RAR 696 êáàéò
|
?
|
| Zhong-Li He, Chi-Ying Tsui, Kai-Keung Chan, and Ming L. Liou, Fellow |
Low-Power VLSI Design for Motion Estimation Using Adaptive Pixel Truncation |
Abstract—We show that traditional waveform coding and 3-D
model-based coding are not competing alternatives, but should be
combined to support and complement each other. Both approaches
are combined such that the generality of waveform coding and the
efficiency of 3-D model-based coding are available where needed.
The combination is achieved by providing the block-based video
coder with a second reference frame for prediction, which is
synthesized by the model-based coder. The model-based coder
uses a parameterized 3-D head model, specifying shape and
color of a person. We therefore restrict our investigations to
typical videotelephony scenarios that show head-and-shoulder
scenes. Motion and deformation of the 3-D head model constitute
facial expressions which are represented by facial animation
parameters (FAP’s) based on the MPEG-4 standard. An intensity
gradient-based approach that exploits the 3-D model information
is used to estimate the FAP’s, as well as illumination parameters,
that describe changes of the brightness in the scene. Model failures
and objects that are not known at the decoder are handled by
standard block-based motion-compensated prediction, which is
not restricted to a special scene content, but results in lower coding
efficiency. A Lagrangian approach is employed to determine the
most efficient prediction for each block from either the synthesized
model frame or the previous decoded frame. Experiments on
five video sequences show that bit-rate savings of about 35% are
achieved at equal average peak signal-to-noise ratio (PSNR) when
comparing the model-aided codec to TMN-10, the state-of-the-art
test model of the H.263 standard. This corresponds to a gain of
2–3 dB in PSNR when encoding at the same average bit rate.
semantic content of the frames and can therefore be used for
arbitrary scenes.
RAR 215 êáàéò
|
?
|
| Yan Yang and Sheila S. Hemami |
Generalized Rate-Distortion Optimization for Motion-Compensated Video Coders |
Abstract—This paper addresses jointly rate-distortion optimal
selection of coding parameters in a general motion-compensated
video coder. The general coder uses variable-block-size motion estimation
and multimode residual coding. This is essentially the optimal
bit-allocation problem for an individual frame at a given
rate constraint. This paper not only gives the general formulation
and solution using the Lagrange multiplier method and dynamic
programming, but also demonstrates howthe general theory
can be adapted and applied to both an MPEG-like coder and a
motion-compensated wavelet coder. Simulations demonstrate that
both proposed coders outperform MPEG (TM5) by 0.7–1.3 dB at
a variety of bit rates, with the gain provided by both better motion
estimation and the joint-parameter optimization. The technique is
applicable to MPEG-compliant coders with fixed block-size motion
estimation and provides a gain of 0.5–0.7 dB over TM5. The optimization
approach can also be applied to distortion-constrained
coding, and therefore allows a fine tuning of either the rate or distortion
to follow any desired profile.
RAR 491 êáàéò
|
?
|
| Luis Salgado, Narciso García, José M. Menéndez, and Enrique Rendón |
Efficient Image Segmentation for Region-Based Motion Estimation and Compensation |
Abstract—An intra-frame segmentation strategy to assist region-
based motion estimation and compensation is presented. It
is based on the multiresolution application of a histogram clustering
and a probabilistic relaxation-labeling algorithm, followed
by a local gradient-based bottom-up merging procedure. Specially
suited for region-based video coding, it strongly differs from other
proposals in that it generates arbitrary shaped image regions with
pixel accuracy at a low computational cost, while allowing full reconstruction
of the segmentation at the decoder without the transmission
of any region description information.
RAR 484 êáàéò
|
?
|
| Yankang Wang, Yanqun Wang, and Hideo Kuroda |
A Globally Adaptive Pixel-Decimation Algorithm for Block-Motion Estimation |
Abstract—For the estimation of block-motion vectors, common
techniques use uniform pixel-decimation patterns to select pixels to
evaluate block-matching criterion, while more recent techniques
use adaptive pixel patterns and have achieved better efficiency.
However, these adaptive techniques still require an initial division
of a block into a set of uniform regions, and therefore, are locally
adaptive in essence. Our proposed scheme, which does not fix any
regions at the beginning and selects pixels only when they have
the features important in determining a match, shows an improvement
in performance over the existing adaptive schemes. Our results
suggest the usefulness of this method in block-motion estimation
for low-bit-rate video coding, particularly in video phone and
video conferencing.
RAR 205 êáàéò
|
?
|
| Jong-Nam Kim and Tae-Sun Choi |
A Fast Full-Search Motion-Estimation Algorithm Using Representative Pixels and Adaptive Matching Scan |
Abstract—The ability to construct intracoded frame from
motion-compensated intercoded frames directly in the compressed
domain is important for efficient video manipulation
and composition. In the context of motion-compensated discrete
cosine transform (DCT)-based coding of video as in MPEG video,
this problem of DCT-domain inverse motion compensation has
been studied and, subsequently, improved faster algorithms were
proposed. These schemes, however, treat each 8 8 block as
a fundamental unit, and do not take into account the fact that
in MPEG, a macroblock consists of several such blocks. In this
paper, we show how shared information within a macroblock,
such as a motion vector and common blocks, can be exploited
to yield substantial speedup in computation. Compared to previous
brute-force approaches, our algorithms yield about 44%
improvement. Our technique is independent of the underlying
computational or processor model, and thus can be implemented
on top of any optimized solution. We demonstrate an improvement
by about 19%, and 13.5% in the worst case, on top of the
optimized solutions presented in existing literature.
preserve the quality of video. The computational efficiency also
leads to higher throughput in dealing with the enormous data
rates in a network environment. Techniques for the conversion
of MC-DCT intercoded frames into DCT intracoded frames
also form the basis for fast extraction of specially reduced
images in MPEG-1 [6] and MPEG-2 video [7].
This problem of DCT-domain inverse motion compensation,
i.e., the conversion of intercoded frames into intracoded frames
directly in the DCT domain without the need for full decompression
for MPEG video was studied in Chang and Messerschmitt
[1], and subsequently in [2], [3]. The idea of the algorithm in
[1] is to represent a target block as a summation of horizontally
and/or vertically displaced anchor blocks. Then, the DCT values
of the target block is constructed using the precomputed DCT
values of the shifting matrices. The general setup is shown in
RAR 165êáàéò |
?
|
| Junehwa Song and Boon-Lock Yeo |
A Fast Algorithm for DCT-Domain Inverse Motion Compensation Based on Shared Information in a Macroblock |
Abstract—A full-search based block-matching algorithm
for motion estimation has a major problem of significant computational
load. To solve this problem, extensive research in
fast-motion estimation algorithms have been carried out. However,
most of them have some degradation in the predicted
image from the reduced computation. To decrease the amount of
significant computation of the full-search algorithm, we propose
a fast block-matching algorithm based on an adaptive matching
scan and representative pixels without any degradation of the
predicted image. By using Taylor series expansion, we obtain the
representative pixels and show that the block-matching errors
from the reference block and candidate blocks are proportional
to the block complexity. With the derived result, we propose a
fast full-search algorithm with adaptive scan direction in block
matching. Experimentally, our proposed algorithm is very efficient
in terms of computational speedup, and is the fastest among all
the conventional full-search algorithms. Therefore, our algorithm
is useful in VLSI implementation of video encoders for real-time
encoding.
RAR 285 êáàéò |
?
|
| Vassilios Christopoulos and Jan Cornelis |
A Center-Biased Adaptive Search Algorithm for Block Motion Estimation |
Abstract—A number of sub-optimal, but faster, search algorithms
have been proposed in the literature, in order to
alleviate the complexity associated with motion estimation by the
full-search method. A new sub-optimal center-biased adaptive
search algorithm for motion estimation is proposed; we refer to
this algorithm as center-biased dynamic MInima Bounded Area
Search (MIBAS) algorithm. The novelty of MIBAS is the checking
point pattern at each subsequent step, composed of points lying
in the area bounded by two local minima found at the present
step, rather than points lying in a small neighborhood around a
local minimum. The simulation results show that, compared to
other fast algorithms, the center-biased MIBAS is more robust
and produces smaller prediction errors and more reliable motion
vectors, while it has a comparable computational complexity.
RAR 114 êáàéò |
?
|
| Jer Min Jou, Pei-Yin Chen, and Jian-Ming Sun |
The Gray Prediction Search Algorithm for Block Motion Estimation |
Abstract—Due to the temporal and spatial correlation of the
image sequence, the motion vector of a block is highly related to
the motion vectors of its adjacent blocks in the same image frame.
If we can obtain useful and enough information from the adjacent
motion vectors, the total number of search points used to find the
motion vector of the block may be reduced significantly. Using
that idea, an efficient gray prediction search (GPS) algorithm for
block motion estimation is proposed in this paper. Based on the
gray system theory, the GPS can determine the motion vectors
of image blocks quickly and correctly. The experimental results
show that the proposed algorithm performs better than other
search algorithms, such as 3SS, CS, PHODS, 4SS, BBGDS, SES,
and PSA, in terms of six different measures: 1) average mean
square error per pixel; 2) average peak signal-to-noise ratio;
3) average prediction errors per pixel; 4) average entropy of
prediction errors; 5) average percentage of unpredictable pels
per frame; and 6) average search points per block.
RAR 268 êáàéò |
?
|
| Jungwoo Lee, and Bradley W. Dickinson, Fellow |
Subband Video Coding with Scene-Adaptive Hierarchical Motion Estimation |
Abstract— This paper presents a new motion-compensated
subband video-coding technique using variable reference-frame
positions for motion estimation. The work builds on temporal
segmentation for determining the reference-frame positions and
incorporates multiresolution motion estimation in the subband
domain. The key advantage of the new algorithm is the complexity
reduction in motion estimation that uses the multiresolution
property of subband decomposition. Temporal segmentation is
performed with the lowest spatial subband, based on the detection
of two types of scene change. The frames of input video are
split into seven spatial subbands, and the motion vectors for
each subband are generated by a hierarchical motion-estimation
algorithm. Blockwise differential pulse code modulation (DPCM)
and a uniform quantizer are used for the lowest subband of the
first frame only, and the subbands of all other cases are coded
by PCM with a dead-zone quantizer. Simulation results show
that our scene-adaptive scheme compares favorably with a fixed
interpolation structure.
RAR 300 êáàéò |
?
|
| Aljoscha Smolic, Bela Makai, and Thomas Sikora |
Real-Time Estimation of Long-Term 3-D Motion Parameters for SNHC Face Animation and Model-Based Coding Applications |
Abstract—In this paper, we present two recursive methods
for the real-time estimation of long-term three-dimensional (3-D)
motion parameters from monocular image sequences suitable for
synthetic/natural hybrid coding face animation and model-based
coding applications. Based on feature point extractions in every
frame, the 3-D motion parameters of a human face are estimated
with a predictive approach. The first method uses a recursive
linear least squares approach and the second employs a nonlinear
extended Kalman filter, which does not rely on a linearized
model of the face motion. Both methods perform a prediction and
correction loop at every time step. Compared to other methods
described in the literature, the recursive and predictive structure
of the proposed estimation process solves the problem of error
accumulation in long-term motion estimation. This makes the
estimation stable and consistent over long periods. Experimental
results are presented for synthetic data and real image sequences,
which demonstrate the performance of the estimation methods
and compare the two approaches.
RAR 414 êáàéò |
?
|
| Christian J. van den Branden Lambrecht, Daniele M. Costantini,
Giovanni L. Sicuranza, and Murat Kunt, Fellow |
Quality Assessment of Motion Rendition in Video Coding |
Abstract—This paper addresses the issue of test and quality
assessment of motion rendition in digital video coding. Motion
estimation and compensation are critical modules in video coders,
as they are the most demanding resources and largely account
for the visual quality of the resulting compressed stream. The
testing of such modules is thus very important. A computational
metric, based on a spatiotemporal model of the human visual
system and of human motion sensing, is proposed and used to
evaluate MPEG-2 compressed video. The metric is able to assess
the quality of motion rendition and exhibits a good correlation
with subjective data.
RAR 355 êáàéò |
?
|
| Jiajun Zhang, M. Omair Ahmad, and M. N. S. Swamy, Fellow |
Quadtree Structured Region-Wise Motion Compensation for Video Compression |
Abstract— The conventional variable-size block motioncompensation
technique, even though superior to the fixed-size
block motion-compensation technique, cannot fully utilize the
motion information of a frame for its partitioning. This paper
presents a quadtree structured region-wise motion-compensation
technique that utilizes more effectively the motion content of a
frame in terms of the shape, size, and location of the partitioned
regions. The proposed technique is based on a new coding
scheme of the quadtree structure, where a two-bit code is used.
The partitioning of a given frame is carried out through the
processes of merging and combining. The merging process
partitions the frame into a number of regions by carrying
out all possible 4-to-1, 3-to-1, and 2-to-1 merges along the
quadtree hierarchy according to some specified criteria, while
the combining process combines some of the partitioned regions
that have the same motion vector into a single region. The
motion vectors of the resulting partitioned regions are coded by
a new coding scheme that uses the temporal correlation of the
motion fields. Test results of applying the proposed method on a
number of MPEG video sequences are included. These results
indicate that the proposed method can provide a significantly
improved rate-distortion performance.
RAR 507 êáàéò |
?
|
| Fang-Hsuan Cheng and San-Nan Sun |
New Fast and Efficient Two-Step Search Algorithm for Block Motion Estimation |
Abstract—Block motion estimation using full search is computationally
intensive. Previously proposed fast algorithms reduce
the computation by limiting the number of searching locations.
This is accomplished at the expense of less accuracy of motion
estimation and gives rise to an appreciably higher mean squared
error (MSE) for motion-compensated images. In this paper, we
present a new fast and efficient search algorithm for block motion
estimation that produces better quality performance and less
computational time compared with a three-step search (TSS)
algorithm. The proposed algorithms are based on the ideas of
dithering pattern for pixel decimation, multiple-candidate for
pixel-decimation-based full search, and center-based distribution
of motion vector. From the experimental results, the proposed
algorithm is superior to TSS in both quality performance (about
0.2 dB) and computational complexity (about half).
Kunt et al. [8], Rao and Yip [9], and Dufaux and Moscheni
[10]. These algorithms had been developed for very different
applications such as image sequence analysis, machine vision,
robotics, image sequence restoration, and video sequence
coding.
RAR 179 êáàéò |
?
|
| Peter H. W. Wong and Oscar C. Au |
Modified One-Bit Transform for Motion Estimation |
Abstract—Motion estimation using the one-bit transform (1BT)
was proposed in [1] to achieve large computation reduction. However,
it degrades the predicted image by almost 1 dB as compared
with full search. In this paper, we propose a modification to the
1BT by adding conditional local searches. Simulation results show
that the proposed modification improves the peak signal-to-noise
ratio (PSNR) significantly at the expense of slightly increased
computational complexity. A variant of the proposed modification
called M2SSFS is found to be particularly good for high quality,
high bit rate video coding. In the MPEG-1 simulation, its PSNR
is within 0.1 dB from that of full search at bit rates higher than
RAR 132 êáàéò |
?
|
| Thomas Wiegand, Xiaozheng Zhang, and Bernd Girod, Fellow |
Long-Term Memory Motion-Compensated Prediction |
Abstract—Long-term memory motion-compensated prediction
extends the spatial displacement vector utilized in block-based
hybrid video coding by a variable time delay permitting the use
of more frames than the previously decoded one for motioncompensated
prediction. The long-term memory covers several
seconds of decoded frames at the encoder and decoder. The
use of multiple frames for motion compensation in most cases
provides significantly improved prediction gain. The variable
time delay has to be transmitted as side information requiring
an additional bit rate which may be prohibitive when the size
of the long-term memory becomes too large. Therefore, we
control the bit rate of the motion information by employing rateconstrained
motion estimation. Simulation results are obtained
by integrating long-term memory prediction into an H.263 codec.
Reconstruction PSNR improvements up to 2 dB for the Foreman
sequence and 1.5 dB for the Mother–Daughter sequence are
demonstrated in comparison to the TMN-2.0 H.263 coder. The
PSNR improvements correspond to bit-rate savings up to 34 and
30%, respectively. Mathematical inequalities are used to speed
up motion estimation while achieving full prediction gain.
RAR 339 êáàéò |
?
|
| Aljoscha Smoli´c, Thomas Sikora, and Jens-Rainer Ohm |
Long-Term Global Motion Estimation and Its Application for Sprite Coding, Content Description, and Segmentation |
Abstract—In this paper, we present a new technique for longterm
global motion estimation of image objects. The estimated
motion parameters describe the continuous and time-consistent
motion over the whole sequence relatively to a fixed reference
coordinate system. The proposed method is suitable for the
estimation of affine motion parameters as well as for higher
order motion models like the parabolic model—combining the
advantages of feature matching and optical flow techniques. A hierarchical
strategy is applied for the estimation, first translation,
affine motion, and finally higher order motion parameters, which
is robust and computationally efficient. A closed-loop prediction
scheme is applied to avoid the problem of error accumulation in
long-term motion estimation. The presented results indicate that
the proposed technique is a very accurate and robust approach
for long-term global motion estimation, which can be used for
applications such as MPEG-4 sprite coding or MPEG-7 motion
description. We also show that the efficiency of global motion
estimation can be significantly increased if a higher order motion
model is applied, and we present a new sprite coding scheme for
on-line applications. We further demonstrate that the proposed
estimator serves as a powerful tool for segmentation of video
sequences.
RAR 2109 êáàéò |
?
|
| Gagan B. Rath and Anamitra Makur |
Iterative Least Squares and Compression Based Estimations for a Four-Parameter Linear Global Motion Model and Global Motion Compensation |
Abstract—In this paper, a four-parameter model for global motion
in image sequences is proposed. The model is generalized and
can accommodate global object motions besides the motions due
to the camera movements. Only the PAN and the ZOOM global
motions are considered because of their relatively more frequent
occurrences in real video sequences. Besides the traditional leastsquares
estimation scheme, two more estimation schemes based
on the minimization of the motion field bit rate and the global
prediction error energy are proposed. Among the three estimation
schemes, the iterative least-squares estimation is observed to be
the best because of the least computational complexity, accuracy
of the estimated parameters, and similar performance as with
the other schemes. Four global motion compensation schemes
including the existing pixel-based forward compensation are
proposed. It is observed that backward compensation schemes
perform similarly to the corresponding forward schemes except
for having one frame delay degradation. The pixel-based forward
compensation is observed to have the best performance. A new
motion vector coding scheme is proposed which has similar performance
as the two-dimensional entropy coding but needs much
less computation. Using the proposed coding scheme with the
pixel-based forward compensation, we obtain 61.85% savings in
motion field bit rate over the conventional motion compensation
for the Tennis sequence.
RAR 461 êáàéò |
?
|
| Yankang Wang and Hideo Kuroda |
Hilbert Scanning Search Algorithm for Motion Estimation |
Abstract— Block-matching algorithms, such as TSS and
DSWA/IS, are widely used for motion estimation in low-bit-rate
video coding. The assumption behind these algorithms is
that when the matching block moves away from the optimal
block, the difference between them increases monotonically.
Unfortunately, this assumption is often invalid, and therefore
leads to a high possibility for the result to be trapped to local
minima. In this research, we proposed a new multiple-candidate
search scheme, Hilbert scanning search algorithm (HSSA), in
which the assumption of global monotonicity is not necessary
and the local monotonicity can be effectively explored with
binary search around each candidate. In HSSA, the number
of initial candidates and a threshold to control the selection
of candidates from one stage to the next can be adjusted to
meet the required search accuracy and/or speed. With properly
chosen parameters, the HSSA converges to their optimal
results faster and with better accuracy than the conventional
block-matching algorithms.
RAR 245 êáàéò |
?
|
| Wolfgang Niehsen and Michael Br¨unig |
Covariance Analysis of Motion-Compensated Frame Differences |
Abstract—The second-order statistics of motion-compensated
frame differences in a low-bit-rate hybrid video coding scheme
with overlapped block motion compensation are investigated.
Based on the empirical covariance sequence, an adequate compound
covariance model is developed. The prediction gain for
motion-compensated frame differences is evaluated, and the performance
of the discrete cosine transform for interframe transform
coding is discussed.
RAR 96 êáàéò |
?
|
| Jie Wei and Ze-Nian Li |
An Efficient Two-Pass MAP-MRF Algorithm for Motion Estimation Based on Mean Field Theory |
Abstract—This paper presents a two-pass algorithm for estimating
motion vectors from image sequences. In the proposed
algorithm, the motion estimation is formulated as a problem of
obtaining the maximum a posteriori in the Markov random field
(MAP-MRF). An optimization method based on the mean field
theory (MFT) is opted to conduct the MAP search. The estimation
of motion vectors is modeled by only two MRF’s, namely, the
motion vector field and unpredictable field. Instead of utilizing
the line field, a truncation function is introduced to handle the
discontinuity between the motion vectors on neighboring sites. In
this algorithm, a “double threshold” preprocessing pass is first
employed to partition the sites into three regions, whereby the ensuing
MFT-based pass for each MRF is conducted on one or two
of the three regions. With this algorithm, no significant difference
exists between the block-based and pixel-based MAP searches any
more. Consequently, a good compromise between precision and
efficiency can be struck with ease. To render our algorithm more
resilient against noises, the mean absolute difference instead of
mean square error is selected as the measure of difference, which is
more reliable according to the knowledge of robust statistics. This
is supported by our experimental results from both synthetic and
real-world image sequences. The proposed two-pass algorithm is
much faster than any other MAP-MRF motion estimation method
reported in the literature so far.
RAR 585 êáàéò |
?
|
| Bo Shen, Ishwar K. Sethi, and Bhaskaran Vasudev |
Adaptive Motion-Vector Resampling for Compressed Video Downscaling |
Abstract—Digital video is becoming widely available in compressed
form, such as a motion JPEG or MPEG coded bitstream.
In applications such as video browsing or picture-in-picture, or in
transcoding for a lower bit rate, there is a need to downscale the
video prior to its transmission. In such instances, the conventional
approach to generating a downscaled video bitstream at the
video server would be to first decompress the video, perform
the downscaling operation in the pixel domain, and then recompress
it as, say, an MPEG bitstream for efficient delivery. This
process is computationally expensive due to the motion-estimation
process needed during the recompression phase. We propose an
alternative compressed domain-based approach that computes
motion vectors for the downscaled (N= 2.N= 2) video sequence
directly from the original motion vectors for the N . N video
sequence. We further discover that the scheme produces better
results by weighting the original motion vectors adaptively. The
proposed approach can lead to significant computational savings
compared to the conventional spatial (pixel) domain approach.
RAR 318 êáàéò |
?
|
| Jie-Bin Xu, Lai-Man Po, and Chok-Kwan Cheung |
Adaptive Motion Tracking Block Matching Algorithms for Video Coding |
Abstract—In most block-based video coding systems, the fast
block matching algorithms (BMA’s) use the origin as the initial
search center, which may not track the motion very well. To
improve the accuracy of the fast BMA’s, a new adaptive motion
tracking search algorithm is proposed in this paper. Based on the
spatial correlation of motion blocks, a predicted starting search
point, which reflects the motion trend of the current block, is
adaptively chosen. This predicted search center is found closer
to the global minimum, and thus the center-biased BMA’s can
be used to find the motion vector more efficiently. Experimental
results show that the proposed algorithm enhances the accuracy
of the fast center-biased BMA’s, such as the new three-step
search, the four-step search, and the block-based gradient descent
search, as well as reduces their computational requirement.
RAR 183 êáàéò |
?
|
| Patrick Bouthemy, Marc Gelgon, and Fabrice Ganansia |
A Unified Approach to Shot Change Detection and Camera Motion Characterization |
Abstract—This paper describes an original approach to partitioning
of a video document into shots. Instead of an interframe
similarity measure which is directly intensity based, we exploit
image motion information, which is generally more intrinsic to
the video structure itself. The proposed scheme aims at detecting
all types of transitions between shots using a single technique
and the same parameter set, rather than a set of dedicated
methods. The proposed shot change detection method is related
to the computation, at each time instant, of the dominant image
motion represented by a two-dimensional affine model. More
precisely, we analyze the temporal evolution of the size of the
support associated to the estimated dominant motion. Besides,
the computation of the global motion model supplies by-products,
such as qualitative camera motion description, which we describe
in this paper, and other possible extensions, such as mosaicing
and mobile zone detection. Results on videos of various content
types are reported and validate the proposed approach.
RAR 2098 êáàéò |
?
|
| John C.-H. Ju, Yen-Kuang Chen, and S. Y. Kung |
A Fast Rate-Optimized Motion Estimation Algorithm for Low-Bit-Rate Video Coding |
Abstract—Motion estimation is known to be the main bottleneck
in real-time encoding applications, and the search for an
effective motion estimation algorithm (in terms of computational
complexity and compression efficiency) has been a challenging
problem for years. This paper describes a new block-matching
algorithm that is much faster than the full search algorithm and
occasionally even produces better rate-distortion curves than the
full search algorithms. We observe that a piecewise continuous
motion field reduces the bit rate for differentially encoded motion
vectors. Our motion estimation algorithm exploits the spatial
correlations of motion vectors effectively in the sense of producing
better rate-distortion curves. Furthermore, we incorporate
such correlations in a multiresolution framework to reduce the
computational complexity. Simulation shows that this method is
successful because of the homogeneous and reliable estimation
of the displacement vectors. In nine out of our ten benchmark
simulations, the performance of the full search algorithm and
that of our subblock multiresolution method is about the same.
In one out of our ten benchmark simulations, our method has
improvement.
RAR 316 êáàéò |
?
|
| Sung Ho Cho, Rin Chul Kim, Seung Seok Oh, and Sang Uk Lee |
A Coding Technique for the Contours in Smoothly Perfect Eight-Connectivity Based on Two-Stage Motion Compensation |
Abstract—In this paper, a new contour-coding technique for
object-oriented video coding is proposed. In our approach, the
two-stage motion compensation technique is considered, in order
to cope with the rather complex motion of the object. While the
object-based motion compensation is performed in the first stage,
the second-stage motion compensation is carried out to search the
best match of the contours, which are not motion compensated
in the first stage. Also, by introducing the notion of the error
band, the current contours can be properly fitted to the motioncompensated
contours using the interframe relationship of the
contours. In addition, an efficient technique for encoding the
contours, simplified by the majority filter, is also proposed. From
the simulation result, it is shown that the proposed technique
provides better performance than the content-based arithmetic
encoding, especially when lossy encoding is allowed. Moreover,
by varying the width N of the error band, it is shown that the
bit amount for the shape information can be adjusted according
to the channel condition.
RAR 774 êáàéò |
?
|
| Zhaohui Sun and A. Murat Tekalp |
Trifocal Motion Modeling for Object-Based Video Compression and Manipulation |
Abstract—Following a brief overview of two-dimensional (2-D)
parametric motion models commonly used in video manipulation
and compression, we introduce trifocal transfer, which is an
image-based scene representation used in computer vision, as
a motion compensation method that uses three frames at a
time to implicitly capture camera/scene motion and scene depth.
Trifocal transfer requires a trifocal tensor that is computed
by matching image features across three views and a dense
correspondence between two of the three views. We propose
approximating the dense correspondence between two of the three
views by a parametric model in order to apply the trifocal transfer
for object-based video compression and background mosaic
generation. Backward, forward, and bidirectional motion compensation
methods based on trifocal transfer are presented. The
performance of the proposed motion compensation approaches
using the trifocal model has been compared with various other
compensation methods, such as dense motion, block motion, and
global affine transform on several video sequences. Finally, video
compression and mosaic synthesis based on the trifocal motion
model are implemented within the MPEG-4 Video Verification
Model (VM), and the results are compared with those of the
standard MPEG-4 video VM. Experimental results show that the
trifocal motion model is superior to block and affine models when
there is depth variation and camera translation.
RAR 694 êáàéò |
?
|
| Pei-Chuan Liu and Wen-Thong Chang |
Recursive Wiener Filter for Motion Parameter Estimation in Three-Parameter Motion Model |
Abstract—Motion compensation is used to reduce the displaced
frame difference (DFD) during the video coding. To increase the
accuracy of the point correspondence during the compensation, a
three-parameter motion model is considered. The matching error
can be significantly reduced as compared with that of the twoparameter
block matching. To derive the parameters, a partial
full search method is used. The full search is used when the zoom
value is set at one. Otherwise, the gradient-based algorithm is
used. Since the DFD is a nonlinear function of the image gradients
and the motion parameters, a linearized model is considered.
To eliminate the linearization error, Wiener filtering is used to
smoothen the DFD to improve the convergence condition of the
iterative gradient search. To make the gradient-based search
more robust to the gradient variation, several gradient estimation
methods are also compared.
RAR 508 êáàéò |
?
|
| Michael C. Chen, and Alan N. Willson, Jr., Fellow |
Rate-Distortion Optimal Motion Estimation Algorithms for Motion-Compensated Transform Video Coding |
Abstract—Motion estimation and compensation is widely used
for exploiting temporal correlation within an image sequence. To
find motion vectors that lead to high compression, most motion
estimation approaches use a source distortion measure, such as
mean-square error (MSE) or mean-absolute error (MAE), as a
search criterion. When incorporated into a closed-loop motioncompensated
(MC) transform video coder, these schemes produce
noisy motion fields which significantly increase the bit-rates
required to represent motion vectors. In view of this problem,
this paper presents a rate-distortion optimal motion estimation
algorithm. The proposed scheme improves rate performance of
the estimated motion field while maintaining the peak signalto-
noise ratio (PSNR) prediction quality of the distortion-based
methods, thereby enabling an efficient bit allocation between
motion information and transform-coded prediction residuals.
For coders in which motion vectors are differentially encoded, the
rate-distortion optimization process is formulated as a shortestpath-
finding problem. Adopting this framework, we show that
the optimal solution for the conventional block-based motion
estimation, followed by one-dimensional (1-D) differential coding
and Huffman coding, can be obtained by using dynamic programming
or the Viterbi algorithm. Since memory and computational
requirements for the optimal algorithm increase dramatically
with the search range, we propose an effective fast algorithm that
closely approximates the optimal performance while requiring
considerably less complexity. When used in a hybrid MC coding
system, the proposed scheme outperforms the conventional MSEor
MAE-optimal motion estimation approach in terms of PSNR
performance under a low-bit-rate constraint. Our experimental
results demonstrate overall gains in the range of 0.3–1.5 dB.
RAR 863 êáàéò |
?
|
| Seongsoo Lee, Jeong-Min Kim, and Soo-Ik Chae |
New Motion Estimation Algorithm Using Adaptively Quantized Low Bit-Resolution Image and Its VLSI Architecture for MPEG2 Video Encoding |
Abstract—This paper describes a new motion estimation algorithm
that is suitable for hardware implementation and substantially
reduces the hardware cost by using a low bit-resolution
image in the block matching. In the low bit-resolution image
generation, adaptive quantization is employed to reduce the
bit resolution of the pixel values, which is better than simple
truncation of the least significant bits in preserving the dynamic
range of the pixel values. The proposed algorithm consists of
two search steps: in the low-resolution search, a set of candidate
motion vectors is determined, and in the full-resolution search,
the motion vector is found from these candidate motion vectors.
RAR 299 êáàéò |
?
|
| Rajesh Rajagopalan, Ephraim Feig, and Michael T. Orchard |
Motion Optimization of Ordered Blocks for Overlapped Block Motion Compensation |
Abstract— While overlapped block motion compensation
(OBMC) [1]–[3] with block matching motion vectors yields
better estimation accuracy than standard block matching,
these estimates may be significantly improved by optimizing the
motion vectors. Optimal motion vectors may be determined by an
iterative and computationally intensive process. However, for a
low-cost system (e.g., videoconferencing [4]), such an approach is
not feasible. An analysis of the compensation errors after motion
optimization reveals that most gains in estimation accuracy
result from the optimization of a fraction of the total number
of blocks in a frame. It is thus conceivable that, by defining
suitable ordering algorithms for blocks, coding systems could
see improved performance by optimizing some number of blocks
based on the ordering depending on available computational
resources. In this paper, with the aid of simulations we first
show that most improvements by optimizing motion are limited
to a few motion vectors. Then we present simple and intuitive
algorithms based on compensation error after OBMC with block
matching vectors to order blocks. Simulation results using these
algorithms for ordering and optimizing motion are presented
for two video sequences. The results reveal improvements
obtained by optimizing motion of blocks from the ordering are
reasonable; however, the improvements are not limited to the
first fraction of blocks from the ordering, suggesting that better
ordering algorithms be investigated in the future.
RAR 94 êáàéò |
?
|
| Dimitrios Tzovaras and Michael G. Strintzis |
Motion and Disparity Field Estimation Using Rate-Distortion Optimization |
Abstract— A rate-distortion framework is used to define a
displacement vector field estimation technique for use in video
coding. This technique achieves maximum reconstructed image
quality under the constraint of a target bit rate for the coding
of the vector sequence. The technique may be adapted so as to
limit its smoothing effect to homogeneous areas and avoid highly
textured areas and edges. Use of this technique is evaluated for
two application areas in which the need for high compression of
displacement vector fields is particularly acute. The first is motion
field coding for very-low-bit-rate image sequence transmission, as
in video-phone applications. The second application area is coding
for the transmission of dense disparity fields. This is needed
for the generation at the receiver of intermediate viewpoints
through spatial interpolation. It is also needed in a number of
other applications requiring accurate depth knowledge, including
three-dimensional medical data transmission and transmission
of scenes to be postprocessed using depth-keyed segmentation.
Experimental results illustrating the performance of the proposed
technique in these application areas are presented and evaluated.
RAR 295 êáàéò |
?
|
| Ut-Va Koc, and K. J. Ray Liu |
Interpolation-Free Subpixel Motion Estimation Techniques in DCT Domain |
Abstract—Currently existing subpixel motion estimation algorithms
require interpolation of interpixel values which undesirably
increases the overall complexity and data flow and
deteriorates estimation accuracy. In this paper, we develop discrete
cosine transform (DCT)-based techniques to estimate subpel
motion at different desired subpel levels of accuracy in the DCT
domain without interpolation. We show that subpixel motion information
is preserved in the DCT of a shifted signal under some
condition in the form of pseudophases, and we establish subpel
sinusoidal orthogonal principles to extract this information. The
proposed subpixel techniques are flexible and scalable in terms
of estimation accuracy with very low computational complexity
O(N2) compared to O(N4) for the full-search block-matching
approach and its subpixel versions. Above all, motion estimation
in the DCT domain instead of the spatial domain simplifies
the conventional hybrid DCT-based video coder, especially the
heavily loaded feedback loop in the conventional design, resulting
in a fully DCT-based high-throughput video codec. In addition,
the computation of pseudophases is local, and thus a highly
parallel architecture is feasible for the DCT-based algorithms.
Finally, simulation on video sequences of different characteristics
shows comparable performance of the proposed algorithms to
block-matching approaches.
RAR 1270 êáàéò |
?
|
| Seongman Kim, Seunghyeon Rhee, Jun Geun Jeon, and Kyu Tae Park |
Interframe Coding Using Two-Stage Variable Block-Size Multiresolution Motion Estimation and Wavelet Decomposition |
Abstract— In this paper, we propose a two-stage variable
block-size multiresolution motion estimation (MRME) algorithm.
In this algorithm, a method to reduce the amount of motion
information is developed, and a bit allocation method minimizing
the sum of the motion information and the prediction error is
obtained in the wavelet transform domain.
In the first stage of the proposed scheme, we utilize a set of
wavelet components of the four subbands in the lowest resolution.
These motion vectors are directly used as motion vectors for the
lowest subband, and are scaled into the initial biases for other
subbands at every layer of the wavelet pyramid. In the second
stage, the bottom-up construction of a quadtree based on the
merge operation is performed. The proposed scheme reduces the
uncompressed bit rate of 8 bits/pixel into 0.212 bits/pixel at 41.1
dB of PSNR for the “Claire” sequence, which can be regarded as
nearly an 11% decrease compared with the conventional method.
RAR 378 êáàéò |
?
|
| Soo-Chang Pei, Ching-Wen Ko, and Ming-Shing Su |
Global Motion Estimation in Model-Based Image Coding by Tracking Three-Dimensional Contour Feature Points |
Abstract—Recently a new type of video coding method called
model-based image coding has attracted much attention as a potential
candidate for low bit-rate visual communication services.
This technique reconstructs the facial image with a preknown
three-dimensional (3-D) human face model and its received model
motion parameters. The parameters of the head motion are
mainly divided into two parts: global motion parameters describe
the rigid movement of the head, such as rotation and translation,
and local motion parameters which deal with the nonrigid movements
of facial expressions, such as the opening and closing of
the mouth and eyes.
In this paper, we propose a new approach which can estimate
the head global motion more robustly and accurately. Comparing
with the existing techniques to match only a few key points, here
we extract 3-D contour feature points and use chamfer distance
matching to estimate head global motion. This can improve and
enhance the contour tracking performance greatly.
We also develop another technique called facial normalization
transform. It maps the facial region of the current input frame
back to the normalized pose of the initial frame. Using this transform,
we can analyze facial expressions at the same orientation
and fixed region. This simplifies the analysis work a lot. Then,
we do our encoding by the clip-and-paste method along with
adaptive codebook technique.
In the following, the coder and decoder system are briefly
described. Since we mainly focus the work on the analysis and
synthesis of the facial portion images, background analysis and
bitstream coding technique will not be discussed in this paper.
RAR 310 êáàéò |
?
|
| Tien-ying Kuo and C.-C. Jay Kuo |
Fast Overlapped Block Motion Compensation with Checkerboard Block Partitioning |
Abstract—The overlapped block motion compensation (OBMC)
scheme provides an effective way to reduce blocking artifacts
in video coding. However, in comparison with the traditional
block motion compensation (BMC), its complexity of motion
estimation increases significantly due to the interdependency
of motion vectors. In this work, a new fast motion estimation
algorithm is proposed for OBMC based on the checkerboard
block partitioning and grouping in encoding. This algorithm,
called the grouped OBMC (GOBMC), effectively decorrelates
dependency among OBMC motion vectors and facilitates the
search process. In comparison with traditional iterative OBMC
motion search, GOBMC performs motion estimation only once
per macroblock at the encoder, and reaches a local optimal
solution with degradation of 0.05–0.1 dB. At the decoding end, we
also propose a fast OBMC reconstruction scheme which reduces
the complexity of multiplication to 38% of that of traditional
OBMC reconstruction while preserving the same visual quality
as obtained via BMC search with OBMC reconstruction.
RAR 262 êáàéò |
?
|
| Dzung T. Hoang, Philip M. Long, and Jeffrey Scott Vitter, Fellow |
Efficient Cost Measures for Motion Estimation at Low Bit Rates |
Abstract— We present and compare methods for choosing
motion vectors for block-based motion-compensated video coding.
The primary focus is on videophone and videoconferencing
applications, where low bit rates are necessary, where motion
is usually limited, and where the amount of computation is
also limited. In a typical block-based motion-compensated video
coding system, motion vectors are transmitted along with a lossy
encoding of the residuals. As the bit rate decreases, the proportion
required to transmit the motion vectors increases. We provide
experimental evidence that choosing motion vectors explicitly
to minimize rate (including motion vector coding), subject to
implicit constraints on distortion, yields better rate–distortion
tradeoffs than minimizing some measure of prediction error.
RAR 474 êáàéò |
?
|
| Showbhik Kalra, and Man-Nang Chong |
Bidirectional Motion Estimation via Vector Propagation |
Abstract—A low-complexity vector propagation (VP) algorithm
is introduced for the estimation of bidirectional motion vector
fields in image sequences. The proposed VP algorithm exploits the
strong correlation between forward and backward motion vector
fields in image sequences. The performance of the VP algorithm
is compared to that of a bidirectional multiresolution blockmatching
(MRBM) motion estimation (ME) algorithm. Computer
simulation results demonstrate that with the VP algorithm, the
computational workload of the bidirectional ME is reduced by
a factor of nearly 2. The robustness of the VP algorithm is
extensively tested using computer generated image sequences and
real movies for a motion picture restoration (MPR) system. It
is shown that the VP algorithm is robust enough to be used
in the computationally demanding MPR algorithm, in which
the performance of the novel VP algorithm is close to that
of a bidirectional MRBM ME algorithm. With this technique,
other video processing systems that desire to take advantage
of bidirectional motion estimation can now do so without an
excessive increase in computing time.
RAR 876 êáàéò |
?
|
| Thomas Meier and King N. Ngan |
Automatic Segmentation of Moving Objects for Video Object Plane Generation |
Abstract—The new video coding standard MPEG-4 is enabling
content-based functionalities. It takes advantage of a prior decomposition
of sequences into video object planes (VOP’s) so that
each VOP represents one moving object. A comprehensive review
summarizes some of the most important motion segmentation and
VOP generation techniques that have been proposed. Then, a new
automatic video sequence segmentation algorithm that extracts
moving objects is presented. The core of this algorithm is an
object tracker that matches a two-dimensional (2-D) binary model
of the object against subsequent frames using the Hausdorff
distance. The best match found indicates the translation the
object has undergone, and the model is updated every frame
to accommodate for rotation and changes in shape. The initial
model is derived automatically, and a new model update method
based on the concept of moving connected components allows for
comparatively large changes in shape. The proposed algorithm
is improved by a filtering technique that removes stationary
background. Finally, the binary model sequence guides the extraction
of the VOP’s from the sequence. Experimental results
demonstrate the performance of our algorithm.
RAR 264 êáàéò |
?
|
| Dae-Sung Cho and Rae-Hong Park |
An Object-Oriented Coder Using Block-Based
Motion Vectors and Residual Image Compensation |
Abstract— This paper proposes a two-stage global motion
parameter estimation method using block-based motion vectors
and a model failure (MF) object compensation algorithm by
object-oriented fractal mapping of the residual image for an
object-oriented coder. In the first stage of the two-stage motion
parameter estimation algorithm, coarse motion parameters are
estimated by fitting block-based motion vectors computed hierarchically
to a six-parameter model, and in the second stage,
the estimated motion parameters are refined by the gradient
method using an image reconstructed by motion parameters
detected in the first stage. The local prediction error by the
six-parameter method is locally reduced by blockwise motion
parameter correction using the residual image. Finally, the MF
object is compensated by object-oriented fractal mapping of the
previous residual image into the current one, in which geometric
affine mapping is followed by the massic transformation. For
MF object compensation, selection between motion parameter
compensation and fractal mapping is achieved by the validity test.
RAR 391 êáàéò |
?
|
| Gerard de Haan, and Paul W. A. C. Biezen |
An Efficient True-Motion Estimator Using Candidate Vectors from a Parametric Motion Model |
Abstract—Some efficient motion estimation algorithms select
their output motion vector from a limited number of likely
correct candidate, or prediction, vectors. In this paper, next to the
known spatial and temporal prediction vectors, an additional and
independent prediction is proposed. This candidate is generated
with a parametric model describing the global motion in a previously
estimated motion vector field. The proposal is elaborated
as an addition to the three-dimensional (3-D) recursive search
block-matching algorithm. The evaluation shows that a subpixel
accurate, true-motion estimator results with a very low operations
count.
RAR 236 êáàéò |
?
|
| Jo Yew Tham, Surendra Ranganath, Maitreya Ranganath, and Ashraf Ali Kassim |
A Novel Unrestricted Center-Biased Diamond Search Algorithm for Block Motion Estimation |
Abstract—The widespread use of block-based interframe motion
estimation for video sequence compression in both MPEG
and H.263 standards is due to its effectiveness and simplicity of
implementation. Nevertheless, the high computational complexity
of the full-search algorithm has motivated a host of suboptimal
but faster search strategies. A popular example is the three-step
search (TSS) algorithm. However, its uniformly spaced search
pattern is not well matched to most real-world video sequences
in which the motion vector distribution is nonuniformly biased
toward the zero vector. Such an observation inspired the new
three-step search (NTSS) which has a center-biased search pattern
and supports a halfway-stop technique. It is faster on the
average, and gives better motion estimation as compared to the
well-known TSS. Later, the four-step search (4SS) algorithm was
introduced to reduce the average case from 21 to 19 search points,
while maintaining a performance similar to NTSS in terms of
motion compensation errors. In this paper, we propose a novel
unrestricted center-biased diamond search (UCBDS) algorithm
which is more efficient, effective, and robust than the previous
techniques. It has a best case scenario of only 13 search points
and an average of 15.5 block matches. This makes UCBDS
consistently faster than the other suboptimal block-matching
techniques. This paper also compares the above methods in
which both the processing speed and the accuracy of motion
compensation are tested over a wide range of test video sequences.
RAR 262 êáàéò |
?
|
| K. J. Boo and N. K. Bose, Fellow |
A Motion-Compensated Spatio-Temporal Filter for Image Sequences with Signal-Dependent Noise |
Abstract—In this paper, a novel spatio-temporal filter is described
for monochrome image sequences with either signalindependent
or signal-dependent noise by considering both spatial
and temporal correlations. With the assumptions of spatiotemporal
separability and temporal stationarity, it is shown that
motion-compensated groups of frames can be decorrelated by
using the Karhunen–Loeve transform. Practical filters that work
well on a variety of image sequences are developed by first
applying the Hadamard transform along the temporal direction.
Subsequently, the parametric adaptive Wiener filter is applied
to each of the resulting approximately decorrelated transformed
images. These transformed images are classified into one average
image and a remaining set of residual images, which provide interesting
and useful interpretations of the type of image sequence.
The filter performance is evaluated by considering different types
of image sequences in the database. The procedure advanced for
processing a sequence of monochrome images can be adapted
for generalization to multispectral images and this possibility is
currently under detailed investigation.
RAR 511 êáàéò |
?
|
| Hangu Yeo, and Yu Hen Hu |
Modular High-Throughput Architecture for Logarithmic Search Block-Matching Motion Estimation |
Abstract— In this paper, a high-throughput modular architecture
for a logarithmic search block-matching algorithm is
presented. The design efforts are focused on exploiting the search
area data dependencies using special data input ordering constraints.
The input bandwidth problem has been solved by a
random access on-chip memory, and a simple address generation
procedure has been described. Furthermore, this architecture can
handle a large search range with unequal horizontal and vertical
spans using a technique called pipeline interleaving. Compared
to the existing architectures for the three-step search BMA, this
architecture delivers a high throughput rate with fewer input
lines, and is linearly scalable.
RAR 845 êáàéò |
?
|
| Viet L. Do and Kenneth Y. Yun |
A Low-Power VLSI Architecture for Full-Search Block-Matching Motion Estimation |
RAR 242 êáàéò |
?
|
| Steve Calzone, Keshi Chen, Chih-Chwen Chuang, Ajay Divakaran, Simant Dube, Lyman Hurd, Jarkko Kari, Gang Liang, Fu-Huei Lin, John Muller, and Hawley K. Rising, III |
Video Compression by Mean-Corrected Motion Compensation of Partial Quadtrees |
Abstract—This paper presents an architectural enhancement to
reduce the power consumption of the full-search block-matching
(FSBM) motion estimation. Our approach is based on eliminating
unnecessary computation using conservative approximation.
Augmenting the estimation technique to a conventional systolicarchitecture-
based VLSI motion estimation reduces the power
consumption by a factor of 2, while still preserving the optimal
solution and the throughput. A register-transfer level implementation
as well as simulation results on benchmark video clips are
presented.
RAR 493 êáàéò |
?
|
| Hirohisa Jozawa, Kazuto Kamikura, Atsushi Sagata,
Hiroshi Kotera, and Hiroshi Watanabe |
Two-Stage Motion Compensation Using Adaptive Global MC and Local Affine MC |
Abstract—This paper describes a high-efficiency video coding
method based on ITU-T H.263. To improve the coding efficiency
of H.263, a two-stage motion compensation (MC) method is
proposed, consisting of global MC (GMC) for predicting camera
motion and local MC (LMC) for macroblock prediction. First,
global motion such as panning, tilting, and zooming is estimated,
and the global-motion-compensated image is produced for use
as a reference in LMC. Next, LMC is performed both for the
global-motion-compensated reference image and for the image
without GMC. LMC employs an affine motion model in the
context of H.263’s overlapped block motion compensation. Using
the overlapped block affine MC, rotation and scaling of small
objects can be predicted, in addition to translational motion.
In the proposed method, GMC is adaptively turned on/off for
each macroblock since GMC cannot be used for prediction in all
regions in a frame. In addition, either an affine or a translational
motion model is adaptively selected in LMC for each macroblock.
Simulation results show that the proposed video coding technique
using the two-stage MC significantly outperforms H.263 under
identical conditions, especially for sequences with fast camera
motion. The performance improvements in peak-to-peak SNR
(PSNR) are about 3 dB over the original H.263, which does not
use the two-stage MC.
RAR 763 êáàéò |
?
|
| Demin Wang, Claude Labit, and Joseph Ronsin |
Segmentation-Based Motion-Compensated Video Coding Using Morphological Filters |
Abstract—The number of regions and length of contour are two basic
constraints in segmentation-based motion-compensated video coding. This
paper presents a coding scheme which focuses on region number reduction,
contour coding, and displaced frame difference (DFD) compression.
One of the important features of the proposed scheme is a spatiotemporal
simplification algorithm based on morphological filters, with
which an image can be segmented into a small number of regions.
Another important feature of the scheme is a segmentation map sampling
technique which reduces contour length by about 50% with a very small
reconstruction error. Experimental results show that, using the proposed
scheme, a high compression ratio can be achieved with a small coding
error for video sequences such as Miss America and Foreman.
RAR 213 êáàéò |
?
|
| Dimitrios Tzovaras, Nikos Grammalidis, and Michael G. Strintzis |
Object-Based Coding of Stereo Image Sequences Using Joint 3-D Motion/Disparity Compensation |
Abstract—An object-based coding scheme is proposed for the
coding of a stereoscopic image sequence using motion and disparity
information. A hierarchical block-based motion estimation
approach is used for initialization, while disparity estimation is
performed using a pixel-based hierarchical dynamic programming
algorithm. A split-and-merge segmentation procedure based
on three-dimensional (3-D) motion modeling is then used to determine
regions with similar motion parameters. The segmentation
part of the algorithm is interleaved with the estimation part
in order to optimize the coding performance of the procedure.
Furthermore, a technique is examined for propagating the segmentation
information with time. A 3-D motion-compensated
prediction technique is used for both intensity and depth image
sequence coding. Error images and depth maps are encoded
using discrete cosine transform (DCT) and Huffman methods.
Alternately, an efficient wireframe depth modeling technique may
be used to convey depth information to the receiver. Motion and
wireframe model parameters are then quantized and transmitted
to the decoder along with the segmentation information. As a
straightforward application, the use of the depth map information
for the generation of intermediate views at the receiver is also
discussed. The performance of the proposed compression methods
is evaluated experimentally and is compared to other stereoscopic
image sequence coding schemes.
RAR 1245 êáàéò |
?
|
| Junavit Chalidabhongse, and C.-C. Jay Kuo |
Fast Motion Vector Estimation Using Multiresolution-Spatio-Temporal Correlations |
Abstract—In this paper, we propose a new fast algorithm for
block motion vector (MV) estimation based on the correlations of
the MV’s existing in spatially and temporally adjacent as well as
hierarchically related blocks.We first establish a basic framework
by introducing new algorithms based on spatial correlation and
then spatio-temporal correlations before integrating them with
a multiresolution scheme for the ultimate algorithm. The main
idea is to effectively exploit the information obtained from the
corresponding block at a coarser resolution level and spatiotemporal
neighboring blocks at the same level in order to select
a good set of initial MV candidates and then perform further
local search to refine the MV result. We show with experimental
results that, in comparison with the full search algorithm, the
proposed algorithm achieves a speed-up factor ranging from 150
to 310 with only 2–7% mean square error (MSE) increase and a
similar rate-distortion performance when applied to typical test
video sequences.
RAR 328 êáàéò |
?
|
| Mei-Juan Chen, Liang-Gee Chen, and Ro-Min Weng |
Error Concealment of Lost Motion Vectors with Overlapped Motion Compensation |
Abstract—A new error concealment algorithm for recovering the lost
or erroneously received motion vectors is presented. It combines the
overlapped motion compensation and the side match criterion to make
the effect of lost motion vectors subjectively imperceptible. The side
match criterion takes advantage of the spatial contiguity and interpixel
correlation of image to select the best-fit replacement among the motion
vectors of spatially contiguous candidate blocks. Particularly, to mask the
blocking artifacts, we incorporate an overlapping technique to create a
subjectively closer approximation to the true error-free image.
RAR 121 êáàéò |
?
|
| Edouard Fran¸cois, Jean-Fran¸cois Vial, and Bertrand Chupeau |
Coding Algorithm with Region-Based Motion Compensation |
Abstract— This paper describes a region-based coding
algorithm developed by Thomson Multimedia and submitted
to MPEG-4 tests of November 1995 and January 1996.
In this algorithm, the segmentation into regions is based
on an advanced motion analysis, successively achieving a
multiresolution motion field estimation and a segmentation
based on a Markovian statistical approach, which insures a good
temporal coherence of segmentation maps and an identification
of covered areas. Moreover, the accurate motion description
allows an intermediate frames interpolation which can increase
the displayed frame rate. Simulation results and MPEG-4 tests
of January 1996 have shown that the algorithm is as efficient as
block-based coding algorithms like MPEG-1 or H.263 for the
compression functionality, while offering temporal scalability
by higher frame rates. Moreover, description of the scene in
coherent motion regions may be seen as an intermediate step
toward object-based functionalities.
RAR 311 êáàéò |
?
|
| Weiping Li, Hugh Q. Cao, Shipeng Li, Fan Ling, Scott A. Segan, Hongqiao Sun, John P. Wus, and Ya-Qin Zhang |
A Video Coding Algorithm Using Vector-Based Techniques |
Abstract—This paper presents an algorithm proposal submitted
to MPEG-4 for video coding. The proposed algorithm addresses
the functionality of improved coding efficiency for compression.
It uses vector-based techniques for coding intraframes
(the first frame and subsequent refreshing key frames) and
motion-compensated difference frames. It uses the same motion
estimation and motion compensation techniques as H.263. A video
frame (I or P frame) is first decomposed into a set of vector
bands using a vector wavelet transform. This stage of vectorbased
signal processing makes subsequent vector quantization in
the vector bands very efficient. Lattice vector quantization is then
used in the vector bands. A 100% labeling efficiency is achieved
for lattice vector quantization by using a set of generalized
labeling algorithms for various important lattices with pyramid
and sphere boundaries. Finally, entropy coding is used to code the
indexes generated from lattice vector quantization. Our coding
results have shown that a gain in peak signal-to-noise ratio
(PSNR) up to 8 dB for intraframe coding and up to 6 dB for
interframe coding can be achieved over H.263. Subjective quality
improvement of the proposed algorithm over H.263 can be easily
observed.
RAR 789 êáàéò |
?
|
| Ming-Chieh Lee, Wei-ge Chen, Chih-lung Bruce Lin, Chuang Gu, Tomislav Markoc, Steven I. Zabinsky, and Richard Szeliski |
A Layered Video Object Coding System Using Sprite and Affine Motion Model |
Abstract—A layered video object coding system is presented
in this paper. The goal is to improve video coding efficiency
by exploiting the layering of video and to support content-based
functionality. These two objectives are accomplished using a sprite
technique and an affine motion model on a per-object basis.
Several novel algorithms have been developed for mask processing
and coding, trajectory coding, sprite accretion and coding,
locally affine motion compensation, error signal suppression,
and image padding. Compared with conventional frame-based
coding methods, better experimental results on both hybrid and
natural scenes have been obtained using our coding scheme. We
also demonstrate content-based functionality which can be easily
achieved in our system.
RAR 879 êáàéò |
?
|
| G.de Haan and H.Huijen |
Motion Estimator For TV-picture Enhacement |
?
RAR 618 êáàéò |
?
|
| Gerard de Haan, Paul W.A.C. Biezen, Henk Huijgen, and Olukayode A. Ojo |
Graceful Degradation in Motion-Compensated Field-Rate Conversion |
Recent motion estimation algorithms have reached a quality level that allows an improved
motion portrayal for field rate conversion systems. As, in practice, still situations may occur in
which motion estimation fails, a strategy for graceful degradation is required, to prevent the
possible artifacts resulting from the processing from outweighing its advantages. In this paper
both a global fall back detection and processing mode is introduced, and a novel method
applying ordered statistical filtering in the up-convertor that realizes a graceful degradation for
local errors in the estimated motion vector field.
RAR 218 êáàéò |
?
|
| B. De Loore, P. Lippens, P. Eeckhout, H. Huijgen, A. Loning,
B. McSweeney, M. Verstraelen, B. Pham, G. de Haan, J. Kettenis |
A video signal processor for motioncompensated field-rate upconversion in consumer television |
The four embedded video signal processors on this IC provide a processing power of
10 Gops. Their architecture was generated from an algorithm description using behavioural
synthesis. The required 25 Gbit/s memory bandwidth was realized by embedding
24 single/dual port SRAM/DRAM instances. The test approach includes full scan,
boundary scan, functional, built-in-self-test and IDDq-test.
RAR 80 êáàéò |
?
|
| D. Bagni, G. de Haan, V. Riva |
MOTION COMPENSATED POST-PROCESSING FOR LOW BIT RATE VIDEOCONFERENCING ON ISDN LINES |
This paper presents a post-processing algorithm for low bit
rate videoconferencing on ISDN lines. The relatively few
images per second that are transmitted during low bit rate
multi-media communications are up-converted after decoding
inside the terminal receiver to an increased frame
rate of 25 Hz or 30 Hz, depending on the display. Applying
advanced motion estimation and compensation techniques
can achieve a significant improvement in motion portrayal
of moving objects.
RAR 75 êáàéò |
?
|
| Olukayode Anthony Ojo and Gerard de Haan |
Robust motion-compensated video upconversion |
Abstract: The quality of eld-rate conversion
improves signi cantly with motion-compensation
techniques. It becomes possible to interpolate new
elds at their correct temporal position. This re-
sults in smooth motion portrayal without loss of
temporal resolution. However, motion vectors are
not always valid for every pixel or object in an
image. Therefore, visible artifacts occur wherever
such wrong vectors are used on the image. One
e
ective method to solve this problem is the use
of non-linear ltering. In this method, a wrongly
interpolated pixel is either substituted or averaged
with neighbouring pixels.
In this paper we introduce and evaluate a
new and very robust upconversion algorithm
which is based on the non-linear ltering ap-
proach. It is unique in that it estimates mo-
tion vector reliability and uses this information
to control the ltering process. This algorithm
outperforms others in its class, especially when
we have complex image sequences.
RAR 3631 êáàéò |
?
|
| E.B. Bellers and G. de Haan |
New Algorithm for Motion Estimation on Interlaced Video |
Many video processing algorithms can pro t from motion information. Therefore, motion estimation is often an
integral part of advanced video processings algorithms. This paper focuses on the estimation of true-motion vectors,
that are required for scan-rate-conversion. Two recent motion estimator methods will be discussed. By combining
these two methods, the major drawbacks of the individual MEs is eliminated. The new resulting motion estimator
proves to be superior over alternatives in an evaluation.
RAR 505 êáàéò |
?
|
| R.J. Schutten, A. Pelagotti and G. de Haan |
Layered motion estimation |
Abstract:{ A layered motion estimation algorithm is proposed that permits quasi-simultaneous
motion estimation / segmentation up to a xed maximum number of layers. The estimation results
in one motion parameter set per layer, and a segmentation map that assigns these sets to di
erent
parts of the image (motion layers). Motion in a layer is modelled with at maximum four parameters
capable of describing pan, tilt and zoom. The concept shows some hierarchy, i.e. a ranking of the
motion layers. In this way the motion parameter estimation concerning one layer is excluding those
parts of the image that have been described by a layer ranked higher in the hierarchy and are not
polluted by parts of the image that are better described by layers ranked lower in the hierarchy. The
concept results in a very low operations count. It has been shown to perform well even in critical
scan rate conversion applications, particularly in picture rate up-conversion. A variant including
three layers has been scheduled to run in real-time on a Philips TriMedia processor.
RAR 472 êáàéò |
?
|
| E.B. Bellers and G. de Haan |
Analysis of sub-pixel Motion Estimation |
The use of interpolation lters in a motion estimator to realize sub-pixel shifts, may lead to unintentional preferences
for some velocities over other. In this paper we analize this phenomenon, focussing on the case of interlaced image
data where the problem leads to the most pronounced errors. Linear interpolators, either applied directly or indirectly
using generalized sampling are discussed. The conclusions are applicable to any type of motion estimator.
RAR 428 êáàéò |
?
|
| Gerard de Haan |
IC FOR MOTION-COMPENSATED DE-INTERLACING, NOISE
REDUCTION, AND PICTURE-RATE CONVERSION |
An IC1 for consumer television applies motion estimation
and compensation for high quality video format
conversion. The chip achieves perfect motion portrayal for
all sources including 24, 25, and 30 Hz film material, and
many display formats. The true-motion vectors are
estimated with a sub-pixel resolution and are used to
optimally de-interlace video broadcast signals, perform a
motion compensated picture rate conversion and improve
temporal noise reduction.
RAR 220 êáàéò |
?
|
| Stefano Olivieriy, Gerard de Haan z, and Luigi Albaniy |
Noise{robust Recursive Motion Estimation for
H.263{based videoconferencing systems |
The key element in realizing low cost real{time software implementations of a H.263 video-
conferencing system is a fast motion estimation algorithm, which only slightly decreases coding
e.ciency. We propose a spatio{temporal recursive estimator that combines an excellent coding
e.ciency with a high computational e.ciency. Experimentally, the new algorithm proves to be
comparable to full{search block matching when encoding typical videoconferencing sequences in
presence of additive noise, even though the computational burden has been greatly reduced.
RAR 138 êáàéò |
?
|
| S. Olivieri, L. Albani ,G. de Haan |
A LOW{COMPLEXITY RECURSIVE MOTION ESTIMATION ALGORITHM FOR H.263 VIDEO CODING1 |
Abstract - The key element in realizing low cost real{time software
implementations of a H.263 videoconferencing system is a fast motion
estimation algorithm, which only slightly decreases coding e.ciency. We
propose a spatio{temporal recursive estimator that combines an excel-
lent coding e.ciency with a high computational e.ciency. Experiment-
ally, the new algorithm proves to be comparable to full{search block
matching when encoding typical videoconferencing sequences in pres-
ence of additive noise, even though the computational burden has been
greatly reduced.
RAR 484 êáàéò |
?
|
| G. de Haan, Philips Research Laboratories, Eindhoven, The Netherlands |
PROGRESS IN MOTION ESTIMATION FOR CONSUMER VIDEO FORMAT CONVERSION |
Two generations of application specific ICs for motion
compensated consumer video format conversion (MCVFC)
are available, and real time DSP software for MCVFC
has recently been demonstrated. The breakthroughs
enabling this progress have come from motion estimation.
The paper gives an overview of the progress achieved in
motion estimation for consumer electronics applications.
to enhance the performance of block matchers. This
improvement is discussed in Section 6, and later led to the
first real-time software object-based motion estimator that
is introduced in Section 7. We draw our conclusions in
Section 8.
RAR 1034 êáàéò |
?
|
| Mark J.W. Mertens ,Gerard de Haany |
A block-based motion estimator capable of handling occlusions |
We present a new block-based motion estimation
strategy, which aims at correctly nding the veloc-
ity of picture blocks, even for background blocks
in occlusion areas. This tritemporal ME calculates
the motion between two pictures, switching the ME
reference plane dependent on an occlusion detector.
We also introduce a retimer, which can transform,
locally in the picture, motion vectors valid for one
time instant to another time instant. The retimer
uses a foreground/background detector, of which we
describe three varieties. Occlusion is a problem that
plagues all block based motion estimation methods,
and hence we see a utility of our method for ap-
plications like e.g. picture rate conversion, video
compression, 3D matching or image sequence object
extraction. An evaluation of the tritemporal estima-
tor is included.
RAR 277 êáàéò |
?
|
| Rimmert Wittebrood and Gerard de Haan |
REAL-TIME RECURSIVE MOTION SEGMENTATION OF VIDEO DATA |
Segmentation is a hot topic for video compression and
interpolation. We introduce a recursive algorithm that
enables real-time motion segmentation of standard
definition video on a DSP. The evaluation of the separate
optimization steps is included.
RAR 138 êáàéò |
?
|
| Rimmert Wittebrood and Gerard de Haan |
REAL-TIME RECURSIVE MOTION SEGMENTATION OF VIDEO DATA ON A PROGRAMMABLE DEVICE |
?
RAR 706 êáàéò |
?
|
| Rimmert Wittebrood and Gerard de Haan |
Feature point Selection for Object Based Motion Estimation on a Programmable Device |
?
RAR 1737 êáàéò |
?
|
| Ralph Braspenningy, Gerard de Haany and Christian Hentschely |
Complexity Scalable Motion Estimation |
Complexity scalable algorithms are capable of trading resource usage for output quality in a near-optimal way. We present
a complexity scalable motion estimation algorithm based on the 3-D recursive search block matcher. We introduce data
prioritizing as a new approach to scalability. With this approach, we achieve a near-constant complexity and a continuous
quality-resource distribution. While maintaining acceptable quality, it is possible to vary the resource usage from below 1
match-error calculation per block on the average to more than 5 match-error calculations per block on the average.
RAR 291 êáàéò |
?
|
| Ralph Braspenning and Gerard de Haan |
ficient Motion Estimation with Content-Adaptive Resolution |
We present a motion estimation algorithm designed to fully exploit the flexibility offered by
programmable platforms. This algorithm adapts its resolution to the image content using the highest
spatial accuracy only for those parts of the image where it is required, i.e. near the borders of moving
objects.
RAR 874 êáàéò |
?
|
