Static image generation method and device

A device for generating a large static image, such as a sprite or a mosaic, from a video sequence including successive video objects VOs, said device comprising, in view of the accretion of said static image in a first accretion stage:

• (A) a motion estimation circuit, provided for estimating a motion information related to the relative motion between the current video object VO(n) of the sequence and the previously generated static image;
• (B) a first warping circuit, provided for defined on the basis of said current video object and said motion information a warped video object WVO(n);
• (C) a first blending circuit, provided for blending the warped video object WV0(n) thus obtained with said previously generated static image, said previously generated static image being thus updated by replacement by the new one;
• characterized in that it also comprises at least a further accretion loop including a second warping circuit, a second blending circuit provided for blending the warped video object thus obtained with the previously generated static image, a memory for storing said generated static image, said memory and said second warping and blending circuits being organized for carrying on the updated static image available at the output of the first blending circuit (n−1) additional accretion steps taking into account on the one hand the same video sequence but considered in the reverse order and on the other hand the estimated motion information corresponding to each concerned video object of said reverse sequence, and, between said warping and blending circuits of said first accretion stage or of anyone of the further accretion loops, means for computing for each picture element a weighting coefficient correlated to the error between the warped video object and the generated static image and taken into account by the following blending circuit during the blending step.