Английские материалы
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| Авторы |
Название статьи |
Описание |
Рейтинг |
| Soo-Chang Pei, and You-Shen Lo |
Color Image Compression and Limited Display Using Self-Organization Kohonen Map |
Abstract—Limited color displays are popular nowadays. Several
methods have been proposed to do color quantization for
limited color displays. Self-organization of Kohonen feature map
(SOFM) is a very useful tool for data clustering. By extracting
a special butterfly-jumping sequence from an image, a neural
network was fed in that sequence of image data for SOFM
training, and a fairly good color table was present to represent
that image. The peak signal-to-noise ratio of the decoded image
is high (about 35 dB in average for 256 color image), and the
perceptual quality is good as well, even with a small set of
color table (for example, 32 or 64 colors). Furthermore, the
training process is fast. For encoding, we also propose an efficient
algorithm based on the Kohonen map ordering property. By
considering that the neighboring image pixels are closely related
and by setting some acceptable thresholds, we can quickly get
an encoded image. For further compressing on the color indexed
image with the limited color palette, we cut the indexed images
into 4 . 4 blocks and send the block vectors into another SOFM
neural network for training. Under the two-dimensional (2-D)
mesh neural structure, SOFM vector quantization on an indexed
image could largely reduce the color shift artifacts and avoid the
requantization problem. About 0.5 b per pixel of coded image can
be easily obtained and has a fairly good perceptual quality. More
importantly, the decoded color indexed images can be readily
displayed. This will reduce the decoder complexity greatly.
RAR 476 кбайт
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| Soo-Chang Pei, Fellow, Ching-Min Cheng, and Lung-Feng Ho |
Limited Color Display for Compressed Image and Video |
Abstract—Many display devices nowadays still allow a limited
number of colors, called color palette, to be displayed simultaneously.
Besides, images and videos in most World Wide Web
databases are in compressed formats. Therefore, it becomes
an important issue to retrieve a suitable color palette from
compressed domain in order to have fast and faithful color
reproduction for these devices. In this paper, the color-palette
design methods for compressed images and videos are presented.
The proposed approaches use the reduced, rather than the whole,
image for the color palette design to avoid the heavy computation
in image or video decompression. Also, for compressed videos, a
shifting-window scheme is proposed to smooth out color variations
in the change of color palette. In these methods, we extend the
dependent scalar quantization algorithm of a single image to
accomplish the color palette design. Experimental results show
that output image quality of proposed methods is acceptable
to human eyes. In addition, empirical results show that the
proposed shifting-window scheme can reduce the main problem
of displaying quantized image sequences, screen flicker.
RAR 2577 кбайт
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| M. A. Klompenhouwer and G. de Haan |
Optimally Reducing Motion Artifacts in Plasma Displays |
Plasma Display Panels (PDPs) suffer from motion artifacts
caused by the subfield driving method. Motion compensation
helps to prevent motion blur and dynamic contouring artifacts.
Our new algorithm for motion compensation is very regular,
inherently avoids rounding errors, and outperforms the earlier
methods.
RAR 111 кбайт
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| E.B. Bellers and G. de Haan |
TOWARDS AN OPTIMAL TELEVISION DISPLAY FORMAT |
The techniques for video format conversion recently have
reached a maturity, where they no longer prohibit application
in the consumer domain because of high price or clear
picture degradation. Given the resulting new freedom, the
question arises how to optimally choose a display format,
i.e. free from the television history. In this paper, we present
an evaluation of various realistic display formats, all using
the same pixel frequency, obtained from a subjective assessment
of critical image material originated either for television,
or obtained from Internet pages.
RAR 47 кбайт
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| Michiel A. Klompenhouwer and Gerard de Haan |
Color Error Diffusion: Accurate Luminance from Coarsely Quantized Displays |
A video signal should use as many bits (gray levels) as possible,
to obtain sufficient amplitude resolution for high quality images.
However, (digital) displays use a limited number of bits. We
propose a modification to the error diffusion algorithm that
enables a decrease in the number of bits, without a decrease in
luminance accuracy.
RAR 305 кбайт
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| Gerard de Haan and Michiel Klompenhouwer |
TEMPORAL ASPECTS OF EMERGING TELEVISION DISPLAYS |
New display principles aim at supreme image quality. The
temporal aspects of these devices sometimes remain
underexposed, and the paper presents an overview of new
artifacts and possible remedies with signal processing.
variation, ?t, resulting from the scanning mismatch as a
linear function of the position on the screen:
RAR 49 кбайт
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| Erwin B. Bellers, Inge de Weerdy, Gerard de Haany, and Ingrid E.J. Heynderickxy |
OPTIMAL TELEVISION SCANNING FORMAT FOR CRT-DISPLAYS |
Current consumer-level priced and state-of-the-art scanrate
converters enable a spatio-temporal decoupling of the
received video and the displayed video. This paper presents
the results of a subjective assessment indicating the preferred
CRT-display format.
RAR 16 кбайт
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| Prof. dr. ir. Gerard de Haan |
Signal processing for enhanced image representation |
The introduction of digital signal processing in consumer video equipment enabled various techniques to
enhance the image representation. This paper provides an overview of techniques developed for high-end
television sets in Philips Research Laboratories Eindhoven over roughly the last decade. Three categories
of enhancement are distinguished: enhancements required to improve poor input video streams, to repair
unfavourable display properties, and to cope with mismatches between source and display format. There
will be some emphasis on the enhancements in the last category, as Philips Research took the lead in this
area. Also the developments in an important enabling technology, motion estimation, are briefly discussed.
RAR 2981 кбайт
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| Gerard de Haan, Senior Member IEEE and Michiel A. Klompenhouwer |
AN OVERVIEW OF FLAWS IN EMERGING TELEVISION DISPLAYS AND REMEDIAL VIDEO PROCESSING |
New display principles aim at supreme image quality. The
temporal aspects of these devices sometimes remain
underexposed in the literature, and the paper presents an
overview of new artifacts and possible remedies with
signal processing.
RAR 650 кбайт
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| Erwin B. Bellers, Ingrid E.J. Heynderickxy, Gerard de Haany, and Inge de Weerdy |
OPTIMAL TELEVISION SCANNING FORMAT FOR CRT-DISPLAYS |
At the time of introduction of the television, the video format
was optimized given both economical and technological
constraints. The resulting video format is not necessarily
optimal for the current display technology. Moreover, current
consumer-level priced and state-of-the-art scan-rate
converters enable a spatio-temporal decoupling of the received
video and the displayed video. This paper presents
the results of a subjective assessment indicating the preferred
CRT-display format.
RAR 1554 кбайт
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| Gerard de Haan, and Michiel A. Klompenhouwer |
Flaws in emerging displays and remedial video processing |
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RAR 3834 кбайт
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| Michiel A. Klompenhouwer and Gerard de Haan |
Subpixel Image Scaling for Color Matrix Displays |
The apparent resolution of matrix displays is increased when the
relative position of the color subpixels is taken into account. This
paper shows that a general method to achieve this for any subpixel
arrangement, can be incorporated in an image scaler at low additional
cost, allowing simple quality trade-off control.
RAR 456 кбайт
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