Telediffusion De France

Pierre Bretillon

Jamal Baina

Gabriel Goudezeune

Denis Masse

Jamal Baïna

The invention relates to a method of synchronizing first and second digital signals presenting digital elements to be put into correspondence, on the basis of time references. The method includes preliminary synchronization of the two digital signals using time references, by putting time references recognized as having the same value in the first and second digital signals into correspondence; and fine synchronization on the basis of a characteristic parameter obtained from the binary streams of the digital elements, and computed for each of the first and second digital signals.

Method for synchronizing digital signals

The invention provides a method of evaluating the quality of an audiovisual sequence by: a) training, comprising allocating a subjective score NSto each of Ntraining sequences S(where i=1, 2, . . . , N) presenting degradations identified by a training vector MOwhich is given to each sequence Sin application of a first vectorizing method, in order to build up a database of Ntraining vectors MOwith subjective scores NS; b) classifying the Ntraining vectors MOintoclasses of scores as a function of the subjective scores NSthat have been allocated to them, so as to formtraining sets EA (where j=1, 2, . . . , k) which havesignificant training scores NSRallocated thereto; c) for each audiovisual sequence to be evaluated, generating a vector MO using said first vectorization method; and d) allocating to the audiovisual sequence for evaluation the significant training score NSRthat corresponds to the closest training set EA.

Method of evaluating the quality of audio-visual sequences

The invention concerns a method for synchronising a video image (IM) spatial position to find the position of an initial digital coding grid (GI), by said image (IM) coding blocks, characterised in that it consists in the following steps: a) moving along the direction of the image (IM) lines and/or along the direction perpendicular to the image (IM) lines, an analysis grid (GA) consisting of coding blocks and corresponding to at least part of the image (IM); b) determining for each position of the analysis grid (GA), the transformed coefficients Fu,v of each block of the analysis grid (GA), using a discrete cosine transform (TCD); and computing for each analysis grid (GA) position, an activity parameter (AM, ES) representing the image activity; c) determining the analysis grid (GA) position for which said activity parameter (AM, ES) has a minimal value.

Method for spatial synchronization of a digitally coded video image and/or for identification of the syntax of a video sequence

The invention concerns a method for assessing the degradation of a video image coded by blocks of picture elements or pixels, comprising the following steps: a) selecting an input image and determining its spatial activity (SA) in an analysis window according to the following sub-steps: i) determining for each block (n, m) the transformed coefficients Fn m (i, y) by a block transform; ii) determining from the transformed coefficients Fn, m (i, y) each block spatial activity bsa; iii) determining the analysis window global spatial activity SA ; b) selecting the output image corresponding to the input image and determining said global spatial activity SA of the output image; c) comparing the spatial activities (SA ) and (SA )

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Metz, France

Pierre Bretillon