Line-sequential pyramid processing of a plurality of raster-scanned image variables
First Claim
1. Apparatus for performing two-dimensional spatial-frequency filterings of each of a plurality of signals each descriptive of a raster-scanned image field sampled-data variable, said raster-scanned image field sampled-data variables having the same number of scan lines in their respective raster scans, said apparatus comprising:
- a respective time compressor for each of said plurality of signals, having the capability of time compressing a full scan line of its respective signal;
means for timing the operation of said time compressors to time-division-multiplex said signals for interleaving successive ones of their respective scan lines on a cyclic basis;
thereby to form a line-sequential composite signal which is a raster-scanned sampled-data description of a plurality of side-by-side image fields; and
a first two-dimensional spatial-frequency filter receptive of said composite signal.
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Abstract
A plurality of raster-scanned image variables are time-compressed and time-division multiplexed on a line-sequential basis for pyramid analysis. The resulting differential pulse code modulation is statistically encoded and assembled together with digital audio code and synchronizing code. The assembler supplies a serial stream of bits to a transmitter. Receiving apparatus for a video teleconferencing station includes a receiver complementary to the transmitter and a parser for separating digital codewords. Those codewords that are statistical codes descriptive of differential pulse code modulation of video are demodulated. The demodulation results are formatted for a pyramid synthesizer. The stream of samples provided as output signal from the pyramid synthesizer is time-division demultiplexed and time expanded to recover the plurality of raster-scanned image variables.
107 Citations
14 Claims
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1. Apparatus for performing two-dimensional spatial-frequency filterings of each of a plurality of signals each descriptive of a raster-scanned image field sampled-data variable, said raster-scanned image field sampled-data variables having the same number of scan lines in their respective raster scans, said apparatus comprising:
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a respective time compressor for each of said plurality of signals, having the capability of time compressing a full scan line of its respective signal; means for timing the operation of said time compressors to time-division-multiplex said signals for interleaving successive ones of their respective scan lines on a cyclic basis;
thereby to form a line-sequential composite signal which is a raster-scanned sampled-data description of a plurality of side-by-side image fields; anda first two-dimensional spatial-frequency filter receptive of said composite signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A combination of:
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a pyramid synthesizer, receptive of the component spatial-frequency spectra in sampled-data form of a raster-scanned sampled-data description of a plurality of side-by-side image fields, for synthesizing said raster-scanned sampled-data description of a plurality of side-by-side image fields; and a respective time decompressor for each of said plurality of side-by-side image fields, arranged to accept as its respective input signal samples descriptive of its respective image field and to provide a raster-scanned output of its respective image field synchronously with each other of said time decompressors. - View Dependent Claims (12)
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13. A method for analyzing the spatial-frequency spectra of first and second raster-scanned video signals, said method comprising the steps of:
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time-division multiplexing said first and second raster-scanned video signals together to form a line-sequential third raster-scanned video signal, and performing a pyramid analysis of said third raster-scanned video signal.
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14. A method for synthesizing first and second raster-scanned video signals from the spatial-frequency spectra of a third raster-scanned video signal of a type as is formed by line-sequential time-division multiplexing of said first and second raster-scanned video signals, said method comprising the steps of:
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performing a pyramid synthesis of said third raster-scanned video signal from its said spatial frequency spectra, time-division demultiplexing said third video signal for separating samples descriptive of scan lines of first video signal and samples descriptive of scan lines of second video signal, and resampling each set of separated samples so the raster scanning of said first video signal and the raster scanning of said second video signal are in synchronism with each other.
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Specification