Telediffusion De France

Teledifusion De France

Jamal Baina

Pierre Bretillon

Denis Masse

Gabriel Goudezeune

Philippe Hocquard

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 )

Method for evaluating the degradation of a video image introduced by a digital transmission and/or storage and/or coding system

Method and system for assessing, at reception level, the quality of a digital signal, such as a digital audio/video signal

The invention relates to a method and to a system for measuring the quality of digital television signals comprising a data stream, the method including measuring quality and producing measurement signals that are representative of quality. The method comprises the following steps: a) selecting a reference time signal (PCR) from the data stream; b) generating a multibit digital clock signal (STC&prime;) from the reference time signal, the phase of the clock signal being locked on the basis of the reference time signal (PCR) and its count being deduced unambiguously from the count of an initial time base (STC); and c) labelling the measurement signals with at least some of the bits (HDT) of the digital clock signal that are meaningful given the nature of the measurements performed.

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Nancy, France

Jamal Baina