METHOD FOR DATA REDUCTION OF DIGITAL PICTURE SIGNALS BY VECTOR QUANTIZATION OF COEFFICIENTS ACQUIRED BY ORTHONORMAL TRANSFORMATION BY MEANS OF A SYMMETRICAL, NEARLY CYCLICAL HADAMARD MATRIX

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.