Telediffusion De France

Etat Francais (cnet)

Thomson Licensing

Interdigital Ce Patent Holdings

Interdigital Madison Patent Holdings, Sas

Christine Guillemot

Dominique Thoreau

Pierre Duhamel

Jean-Claude Carlac'h

Ronan Boitatd

Process and device for the compression of image data by a mathematical transformation implemented at low cost, particularly for the transmission at reduced speed of sequences of images. The objective is to provide an economical method in 'silicon area - processing speed' cost to implement a mathematical transformation of the DCT type, on arrays of pixels, suitable for image compression. According to the invention, the method consists essentially of combining a permutation (1) of each block of pixels with a series of one dimensional FFT (211, 213). A series of variants is obtained by adding or not adding steps of matrix calculation (22) of reconstitution of a complex 2D-FET, of rotations (3) of reconstitution of the DCT, and/or of suppression of the imaginary coefficients.

Process and device for the compression of image data by mathematical

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Rennes, France

Christine Guillemot