Compression of video signals

Details Compression of video signals Compression of video signals

1991-12-19

1993-06-29

Britton, Howard W.

Facsimile and static presentation processing

Facsimile

Specific signal processing circuitry

358138, 382 56, H04N 7133

Patent

active

052239268

ABSTRACT:
A digital video signal is compressed by spatial sub-band filtering to form data sets constituting respective sub-bands of the two-dimensional spatial frequency domain. The data sets for a field or frame are stored. A first sequencer controls writing, in accordance with a desired sequence, of the stored data to a quantizer in which they are quantized in accordance with respective values, those values being such that the amount of quantization of at least a data set constituting a sub-band to which dc luminance information of the signal is at least predominantly confined is less than the average of the amounts of quantization of the remaining data sets. The quantized data sets are then encoded in an entropy encoder which has a first coding portion for coding quantized data representative of dc luminance information and a second coding portion for coding quantized data representative of ac luminance information. A second sequencer, which may be the same sequencer as the first sequencer, controls operation of the quantizer so that each datum (sample) written thereto is appropriately quantized, and controls operation of the entropy encoder so that each quantized sample is directed to the appropriate one of the first and second coding portions.

REFERENCES:
patent: 4969040 (1990-11-01), Gharavi
patent: 5109451 (1992-04-01), Aono
Optical Engineering vol. 27, No. 7, Jul. 1988, Bellingham US pp. 574-586; G. Karlsson et al.: Subband Coding of Video For Packet Networks see paragraph 3-paragraph 42; FIG. 4-8.
Signal Processing Image Communication vol. 2, No. 3, Oct. 1990, Amsterdam, NL pp. 333-341; K. Irie et al.: Adaptive Sub-band DCT coding for HDTV Signal Transmission see paragraph 2; FIG. 1-4; tables 1-4.
Proceedings ICASSP'89, vol. 3, 23-26 May 1989, IEEE, New York, US, pp. 1945-1948, R. Safranek et al. A Perceptually Tuned Sub-band Coder With Image Dependent Quantization and Post-quantization Data Compression.
IEEE Transactions on Circuits and Systems, vol. 35, No. 2, Feb. 1988, New York US pp. 258-261 H. Gharavi: Low Bit-rate Video Transmission For ISDN application see paragraph 2.5; FIG. 2.
IEEE Transactions on Communications. vol. COM34, No. 3, Mar. 1986, New York US pp. 310-319; E. Dubois et al.: Encoding and Progressive Transmission of Still Pictures in NTSC Composite Format Using Transform Domain Methods.

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