Siemens Aktiengesellschaft

Bernard Hammer

Achim Von Brandt

Stefan Prange

Heribert Geib

J&uuml;rgen Pandel

For the purpose of bidirectional movement-compensated interpolation, it is proposed, when decoding compressed video sequences, completely to decode only one of the two reference frames. Only those respective picture areas of the other reference frame are decompressed which overlap with the picture area to be determined of the interpolated frame, taking account of a displacement corresponding to the movement compensation. As a result, a considerable reduction in the memory requirement of the decoding hardware is possible.

Method for decoding compressed video data with a reduced memory requirement

A method for data reduction of digital image sequences in heirarchic fashion by means of a multi-stage coder on the basis of vector quantizing and movement compensation, as well as reconstruction of these image sequences by means of a multi-stage decoder. An input image signal is represented in a plurality of image signals having different spatial resolutions by means of a cascade of L identical low-pass filters having subsequent sub-scanning, whereby the spatial resolution and the data volume of the input image signal in the horizontal and the vertical directions are respectively reduced by a factor R in every cascade stage, and whereby the input signal is referenced 'resolution level L' and the low-pass filter image signal having the smallest resolution is referenced 'resolution level .0.'. The chronologically preceding, reconstructed, movement-compensated image signal is represented in a plurality of image signals having different topical resolution in the same way. The samples of the resolution levels are subdivided into blocks, whereby the 'resolution level .0.' has the block size '1.times.1' and, for the next, the block size is horizontally and vertically increased by the factor R with every further resolution level but a block assumes the maximum block size N.times.N.

Method for data reduction of digital image sequences

A method for data reduction of digital video signals by vector quantization of coefficients acquired by orthonormal transformation with a symmetrical, nearly cyclical Hadamard matrix, employs formation of a mean value coefficient and a plurality of structure coefficients from a plurality of blocks formed from the input signal in a Peano curve arrangement, these coefficients being in part only scalarly quantized and in part both scalarly as well as vectorially quantized. The quantization takes place in a coder having at least two stages interconnected cascade-like. The reconstruction of the video signal takes place in a decoder, having an identical plurality of stages. The method allows the noise amplitude of the video signal acquired after back-transformation to be adapted to the visibility thresholds of the human visual system.

Method for data reduction of digital video signals by vector

A method and apparatus for data reduction of digital picture signals by vector quantizing of coefficient acquired by orthonormal transformation using a symmetrically, nearly cyclical Hadamard matrix, includes means for deriving a mean value coefficient and a plurality of structure coefficients from a plurality of blocks formed from the input signal and resorted by means of a Peano curve, said coefficients being in part only scalarly quantized, and in part scalarly and vectorly quantized. The apparatus and method allows a noise amplitude of the picture signal acquired after back transformation to be adapted to visibility thresholds of the human visual system according to CCIR recommendation 500-1.

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Pfaffing, Germany

Bernard Hammer