Facsimile and static presentation processing – Static presentation processing – Attribute control
Patent
1989-01-09
1990-08-21
Shepperd, John W.
Facsimile and static presentation processing
Static presentation processing
Attribute control
H04N 978
Patent
active
049511297
ABSTRACT:
Digital prefiltering of luminance and chrominance components for an encoded video signal is performed to prevent cross color and dot crawl errors when the encoded video signal is decoded. The luminance component is filtered using a two- or three-dimensional chrominance bandpass filter to generate luminance correction limiting values corresponding to cross color errors that would occur when a conventionally encoded video signal is decoded. The luminance component also is filtered individually in each dimension, horizontally, vertically and/or temporally, to obtain luminance dimensional correction values. From the luminance correction limiting values and corresponding luminance dimensional correction values, luminance correction values are obtained by a two step decision process. The luminance correction values are added to the luminance component to provide the prefiltered luminance component. In like manner chrominance correction limiting values and chrominance dimensional correction values are generated and used to obtain chrominance correction values that are added to the chrominance component to provide the prefiltered chrominance component. The prefiltered components are combined, along with synchronizing signals, to produce the encoded video signal.
REFERENCES:
patent: 4656502 (1987-04-01), Hausdorfer
patent: 4683490 (1987-07-01), Strolle et al.
patent: 4731660 (1988-03-01), Faroudja et al.
Faroudja et al., Improving NTSC to Achieve Neat-RGB Performance, SMPTE Journal, Aug. 1987, pp. 750-761.
Dubner Computer Systems, Inc.
Gray Francis I.
Shepperd John W.
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