US 4,827,336 A · Symbol code generation processing from interframe DPCM of TDM'd spatial-frequency analyses of video signals

Abstract

At a sending station in a digital television transmission system embodying the invention, time-division multiplexing either of the spatial-frequency analyses of the video signals from a television camera or of their interframe DPCM responses, both of which have uniform coding rates, is completed prior to symbol coding of interframe DPCM samples. This obviates the problems of time-division multiplexing symbol codes of variable length and of irregular coding rate. Time-division multiplexing is done so as to facilitate symbol coding protocols which include run-length encoding of DPCM samples. At a receiving station in the digital television transmission system time-division demultiplexing takes place after symbol decoding, being done on a per scan line basis.

Claims25

Dependent claims

Improved sending apparatus for a digitally televised sequence of image frames described by a plurality of component video signals, which sending apparatus is of the type including means for interframe differential pulse code modulation (DPCM) of said component video signals, means for run length encoding of zero value samples from said DPCM modulated signals and means for statistical coding of the run length codes and of non zero value samples of said modulated and run length encoded signals, wherein the improvement comprises means for time division multiplexing said component video signals together prior to said differential pulse code modulation, run length encoding and statistical coding procedures.

Improved sending apparatus for a digitally televised sequence of image frames described by a plurality of component video signals, which sending apparatus is of the type using interframe differential pulse code modulation (DPCM) of said component video, signals followed by statistical coding said improved sending apparatus comprising:

means responsive to each of at least one digital video signal descriptive of a sequence of image frames for performing a spatial frequency analysis thereof thereby to generate for each said digital video signal a respective set of subband signals, at least some of which subband signals in each set are generated at a lower sampling rate than the digital video siqnal used to generate them;
a differential pulse code modulator for generating a differential pulse code modulation (DPCM) signal of interframe type from each subband signal;
a time division multiplexer for interleaving lines of said differential pulse code modulation signals of interframe type together in time, thereby to form a digital sample stream;
and
a symbol coder for generating symbol codes descriptive of samples in said digital sample stream.

2 more elements

Improved sending apparatus for a digitally televised sequence of image frames described by a plurality of component video signals, which sending apparatus is of the type including means for interframe differential pulse code modulation of said component video signals, followed by means for run length encoding of zero value samples, followed by means for statistical coding of run length codes and of non zero value samples, wherein the improvement comprises means for time division multiplexing the differential pulse code modulation response of said component video signals prior to said statistical coding procedures.

Sending apparatus for a digitally televised sequence of image frames, said sending apparatus comprising:

a number at least one of subtractors, each having a respective minuend input port receptive of a respective digital video signal descriptive of a sequence of image frames, each having a respective subtrahend input port receptive of a prediction signal for the respective digital video signal received at its respective minuend input port, and each having a respective difference output port for supplying a respective digital error signal;
means responsive to each said digital error signal descriptive of a sequence of image frames for performing a spatial-frequency analysis thereof thereby to generate for each said digital error signal a respective set of subband signals, at least some of which subband signals in each set are generated at a lower sampling rate than the digital video signal used to generate them;
means for generating from said subband signals digital pulse code modulation responses time-division multiplexed together in a digital sample stream;
a quantizer responding to said digital sample stream to generate a more coarsely quantized digital sample stream:
a symbol coder for qenerating, as an output signal from said sending apparatus, symbol codes descriptive of said more coarsely quantized digital sample stream;
and
apparatus for generating from said more coarsely quantized digital sample stream respective predicted values for each said subtractor respective subtrahend input port.

4 more elements

Dependencies are inferred from the claim text.

Symbol code generation processing from interframe DPCM of TDM'd spatial-frequency analyses of video signals

Life of this patent

Symbol code generation processing from interframe DPCM of TDM'd spatial-frequency analyses of video signals

Life of this patent

Abstract

Claims25