Process and device for the compression of portions of images

1. A method of compressing a block having a size L×H of a sequence of images, the method comprising using a processor to perform the following steps, in a repetitive manner, on said block:

searching, in one of the images of the sequence of images, for the zone of L×H pixels that is the most similar to said block;

determining whether the resemblance between said zone and said block responds to predetermined criteria;

if said resemblance responds to said criteria, storing a motion vector which indicates the distance between the block and the most similar zone found;

if said resemblance does not respond to said criteria, and if the block does not have a predetermined minimum size, cutting said block into sub-blocks and performing a supplemental repetition on each of said sub-blocks, and

if said resemblance does not respond to said criteria, and if said block has a predetermined minimum size, storing the block so that while the block is being stored in the course of which the block is compressed without reference to a reference image:

wherein said criteria depends on the residue resulting from the prediction.

2. The method according to claim 1 , wherein the searching step includes conjointly (a) determining a transformation and a zone that supplies the transformed zone which is the most similar to said block, determining, during the determining step (a), (b) whether the resemblance between said transformed zone and said block responds to predetermined criteria, and

the storing step includes storing the vector data representative of said transformation, if said zone after said transformation is the zone most closely resembling the vector.

3. The method according to claim 2 , wherein the searching step includes searching in a plurality of images of the sequence of images, for the zone of L×H pixels that is the most similar to said block, and the vector storing step includes storing data representative of the image which comprises said zone.

4. The method according to claim 2 , wherein the searching step includes searching only in the preceding image of the sequence of images, for the zone of L×H pixels that is the most similar to said block.

5. The method according to claim 2 , wherein the cutting out step includes cutting out said block into two sub-blocks having the same dimensions.

6. The method according to claim 1 , wherein the searching step includes searching in a plurality of images of the sequence of images, for the zone of L×H pixels that is the most similar to said block, and the vector storing step includes storing data representative of the image which comprises said zone.

7. The method according to claim 6 , wherein the searching step includes searching only in the preceding image of the sequence of images, for the zone of L×H pixels the most similar to said block.

8. The method according to claim 6 , wherein the cutting out step includes cutting out said block into two sub-blocks having the same dimensions.

9. The method according to claim 1 , further including searching only in the preceding image of the sequence of images during the search step for the zone of L×H pixels that is the most similar to said block.

10. The method according to claim 9 , wherein the cutting out step includes cutting out said block into two sub-blocks having the same dimensions.

11. The method according to claim 1 , further including cutting, during the cutting out step, said block into two sub-blocks having the same dimensions.

12. The method according to claim 11 , wherein the cutting out step includes cutting out the block or the sub-block, on the one hand, vertically and, on the other hand, horizontally and, selecting, during the selecting step, including selecting the cutting out which optimizes the overall resemblance of the sub-blocks generated by each of said acts of cutting out, with zones of said images of the image sequence.

13. A computer arrangement for performing the method of claim 1 .

14. A device for compressing a block having a size L×H, the block being a sequence of images, the device comprising:

a treatment arrangement for controlling, in a repetitive manner, for each block:

a search arrangement for searching, in one of the images of the sequence of images, for a zone of L×H pixels that most resembles said block;

a determining arrangement for determining whether the resemblance between said zone and said block meets predetermined criteria, all of which depend on the L×H dimensions of the block;

a storage arrangement for (a) storing a motion vector indicating the distance between the block and the most similar zone found in response to the determining arrangement determining the resemblance meets the criteria, and (b) compressing the block without reference to a reference image and storing the compressed block in response to the determining arrangement determining the resemblance does not meet said criteria and said block having at least a predetermined minimum size; and

a cutting arrangement for cutting said block into sub blocks and for performing a supplemental repetition for each of said blocks, the cutting arrangement being arranged for performing the cutting and supplemental repetition operations in response to the resemblance not meeting said criteria and the block not having the predetermined minimum size.