Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Patent
1997-11-20
2000-05-09
Britton, Howard
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
348391, 348392, 382232, 382239, 382240, H04N 166, H04N 712
Patent
active
060614005
ABSTRACT:
Techniques for identifying blocks of pixels, referred to as constant block regions, having approximately the same intensity in terms of luminance values, are discussed. High contrast vertical and/or horizontal edges will cause significant prediction errors in images generated by reduced resolution decoders under certain conditions. Methods for assessing when such conditions exist and a significant prediction error is likely to occur are described. In addition methods and apparatus for minimizing the effect of such prediction errors in downsampling decoders are also described. One specific embodiment is directed to a new video decoder which decodes portions of a single image, e.g., frame, at different resolutions. Areas of the image along high contrast vertical or horizontal edges are decoded at full resolution while other portions of the same image are decoded at reduced resolution. By decoding and storing portions of reduced resolution images at full resolution for reference purposes, the risk of prediction errors resulting from the use of downsampling on reference frames is reduced.
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Fuhrer Jack
Henderson John
Pearlstein Larry
Britton Howard
Hitachi America Ltd.
Straub Michael P.
Vo Tung
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