Abstract: A method of coding an image or a sequence of images generating a flow of data in the form of groups of blocks, at least one group of blocks containing image blocks having a resolution and a quality level of identical quantification, the method including the following steps for the at least one group of blocks, of a) a first coding so that each block of the at least one group of blocks has at least one associated parameter that is given a first value, and b) a second coding for giving the associated parameter for at least one block of the at least one group of blocks a second value, so that for the at least one block, the first and second values given for the parameter can be combined during decoding to provide a value assigned to the parameter.

Abstract: A method and apparatus for encoding a sequence of images by predicting at least one current image by forward motion compensation from at least one reference image. Prediction implements, for at least one current block of the current image: forward projection of a block of the reference image on the current image, delivering a projected block at least partially overlapping the current block; partitioning the current block delivering a sub-block at least partially overlapped by at least one projected block; and at least one iteration of the following steps for at least one overlapped sub-block: checking that the overlapped sub-block complies with a predetermined allotting criterion; with a positive check, allotting, to the overlapped sub-block, one of the projected motion vectors; and with a negative check, and so long as a predetermined minimum size is not reached for the overlapped sub-block: partitioning of the overlapped sub-block.

Abstract: Techniques are provided for encoding and decoding image data. The techniques implement a prediction of data of a current block based on at least one already encoded block or reference block, wherein said prediction step takes into account a set of encoded blocks adjacent to said current block and including blocks that have not yet been considered according to said writing path order. Encoding includes the steps of: generating a dependence tree associating a current block with at least one reference block from which the predicted block associated with the current block has been predetermined; and inserting information representative of said dependence tree into said set of data associated with each block.

Abstract: A method is provided for encoding a sequence of images generating a data stream in the form of a structure of embedded data layers of n successive levels each of which corresponds to the predetermined resolution of said images. Said method comprises an encoding stage, which encodes at least one of said layers of an n+1 level by prediction on the basis of said level n layer and encodes each data layer of the level n in the form of a base sub-stream and, optionally, in the form of at least one enhancement sub-stream enabling to obtain at least one version of the enhanced quality of said images. The method also encodes, for at least one data layer of the n level, at least one single sub-stream enabling to reconstruct the version of said images at said level n resolution with a quality higher than said enhanced qualities, wherein said single sub-steam of the level n layer is not used during the prediction encoding of the layers of a level other than the level n.

Abstract: A method is provided for encoding an image represented by a sequence of symbols. The method includes the following steps: defining subsequences within the sequence; and going through the subsequences applying the following sub-steps for a routine subsequence: determining an adjacent routine encoded group including two previously encoded subsequences, one of which belongs to an adjacent encoded group associated with a subsequence that is separate from the routine subsequence; initializing a routine probability of occurrence of a symbol, taking into account two known probabilities of occurrence of the symbol, relating to two previously encoded subsequences of the adjacent routine encoded group; the consecutive entropic encoding of the symbols, and updating the routine probability of occurrence; and storing the routine probability of occurrence after encoding the last symbol.

Abstract: A method and apparatus are provided for encapsulating a plurality of data substreams encoded in a bit stream, wherein the encoded data substream is obtained by entropy encoding of a symbol subsequence representing an image or a series of images. The method includes grouping data substreams into substream pairs according to an iterative traversal order predetermined from the plurality of substreams, and on the basis of a pair of the substreams, obtaining a symmetrical pair by reversing a data order making up the second substream of the pair. The obtained pairs are then concatenated within a sequence. The binary stream is created by encapsulating the sequence and information related to a number of substreams and related to the sizes of pairs of symmetrical substreams.

Abstract: A method and apparatus are provided for coding a signal from images, the images being split into sub-blocks of pixels. The method includes grouping at least two sub-blocks into at least one block of larger size, when the sub-blocks comply with at least one predetermined grouping criterion. A prediction is performed by applying at least one mode of motion prediction using at least two distinct motion prediction vectors, for at least one block of larger size, the motion prediction vectors being associated respectively with sub-sets of the block of larger size, comprising at least one of the sub-blocks of the block of larger size. The sub-sets are predefined and distinct.

Abstract: A video image sequence including coefficients of frequency sub-bands with different spatial resolutions is coded. A data stream including at least one restitution level (Niv N?2, Niv N?1, Niv N) is formed. The restitution levels have coefficients of frequency sub-bands whose spatial resolution equals a spatial resolution of the restitution level. There are inserted, in at least one restitution level, coefficients of frequency sub-bands with a spatial resolution higher than the spatial resolution or resolutions of the restitution level.

Abstract: A method is provided for encoding an image signal that includes motion information, by selecting a motion vector from among a set of at least three candidate vectors for at least one actual block of an actual image to be encoded. The method includes: determining an optimal-selection subset containing some of the candidate vectors; selecting the motion vector from among the vectors of the optimal-selection subset; and inserting into the signal a piece of information designating the motion vector selected from among the vectors of the optimal-selection subset.

Abstract: A method and apparatus are provided for encoding an image sequence. The method includes the following steps, for at least one group of blocks of an image: determining, for each block, at least one parameter characteristic of said block; forming at least one cluster including the blocks having at least one similar characteristic parameter; encoding the blocks of said cluster, the similar characteristic parameter(s) associated with said cluster being encoded only once; encoding the blocks that do not belong to any cluster, the characteristic parameter(s) associated with each of said blocks not being encoded; generating a data stream; and inserting into said stream, at least one piece of information on the partitioning of the group(s), in order to identify the outer block(s) within a group.

Abstract: A method is provided for encoding an image sequence, including the step of dividing a reference image into blocks and a prediction step that includes the following steps: determining monitoring vectors associated with a common image and dividing the same into sub-blocks defining a first partition; determining monitoring vectors associated with an image to be compensated and dividing the same into sub-blocks defining a first partition obtaining a common partitioning into basic sub-blocks; determining first and second sets of monitoring vectors for the basic sub-blocks; movement-compensating a sub-block of the image to be compensated towards a sub-block of the common image.

Abstract: A method is provided for coding an image sequence, including splitting a current image into blocks of standard size, termed macroblocks. For at least one current macroblock of the current image, the method further includes: constructing at least one block of greater size than the current macroblock, termed a large block, which includes the current macroblock and at least one neighbor macroblock in the current image, taking account of characteristics of the current image; coding the large block, delivering base coding information, making it possible to reconstruct a base layer of said current image, and for at least one large block, determining enhancement information associated with at least one macroblock present in the large block.

Abstract: A method is provided for predicting an image by compensation during forward movement from at least one reference image. For at least one block of a reference image, referred to as a reference block, the prediction method includes the following steps: determining at least one piece of movement information, representing a movement between said reference block and a matching block in the image to be predicted; determining at least one enlarged block, including the reference block and at least one point of a block adjacent to said reference block in the reference image; and determining a prediction value for at least one point of the image to be predicted from the at least one enlarged block and from the movement information determined for the reference block.

Abstract: Techniques are provided for encoding and decoding image data. The techniques implement a prediction of data of a current block based on at least one already encoded block or reference block, wherein said prediction step takes into account a set of encoded blocks adjacent to said current block and including blocks that have not yet been considered according to said writing path order. Encoding includes the steps of: generating a dependence tree associating a current block with at least one reference block from which the predicted block associated with the current block has been predetermined; and inserting information representative of said dependence tree into said set of data associated with each block.

Abstract: A method and apparatus are provided for coding a sequence of images. The method includes a step of coding at least one block of a current image of the sequence, implementing a prediction associating the block with at least one corresponding block in a reference image. The prediction includes the following steps, for at least one given block of the current image or of the reference image: determination of a plurality of control vectors for the block; at least one splitting of the block into sub-blocks; determination of a plurality of control vectors for the sub-blocks; and determination of a prediction value for at least one point of the current image. Moreover, the method includes a step of inserting, into a signal representative of the sequence, information regarding reconstruction of the control vectors for the given block.

Abstract: A method of filling occluded areas of a depth or disparity map estimated from at least two images and consisting of a matrix of pixels forming a set of lines and columns, each pixel of the map being associated with a depth or disparity value (pixel value) and any pixel of an occluded area (invalid pixel) being associated with a pixel value identifiable as being invalid. This method comprises a step of processing each line of the map pixel by pixel in a predefined direction and assigning each invalid pixel Pi encountered on a current line a value determined as a function of the values associated with the pixels in a predefined vicinity around the first valid pixel P1, if any, that follows the invalid pixel Pi on the current line and the value V(P1) of which corresponds to a greater depth or a lesser disparity relative to the value V(P0) of the last valid pixel P0, if any, that precedes the invalid pixel Pi on the current line.

Abstract: A method and apparatus are provided for coding an image or a sequence of images, generating a data stream including data representative of pixel groups, referred to as blocks, in one of the images. The method includes: grouping blocks in a cluster of blocks according to the proximity of their respective values corresponding to at least one block parameter to be coded; determining a value of the parameter, the value being characteristic of said group of blocks; coding blocks of the cluster, where the values of the blocks for the parameter are coded implicitly by inheritance of the characteristic value or are coded as refinements relative to the characteristic value, and coding a data structure associated with the cluster of blocks, the data structure including data associated with the characteristic value.

Abstract: Method of coding an image or a sequence of images generating a flow of data in the form of groups of blocks, at least one group of blocks containing image blocks having a resolution and a quality level of identical quantification, characterized in that said method comprises at least the following steps for the at least one group of blocks, of a) a first coding so that each block of the at least one group of blocks has at least one associated parameter that is given a first value, and b) a second coding for giving said associated parameter for at least one block of said at least one group of blocks a second value, so that for said at least one bloc, the first and second values given for said parameter can be combined during decoding in order to provide a value assigned to said parameter.

Abstract: A method is provided decoding a digital image signal in a decoding terminal that uses a variable-complexity decoding, enabling, for at least one step in the decoding, selection of at least one decoding tool from at least two available decoding tools. The method includes the following steps: identifying from the images control images and intermediate images; applying to each of the control images, for at least one step of the decoding, at least one predetermined decoding tool imposed by the signal; applying to at least one of the intermediate images, for at least one step of the decoding, at least one decoding tool selected by the decoding terminal and not imposed by the signal.

Abstract: A method and apparatus are provided for decoding a signal representative of an image sequence. The method includes extracting motion tubes from the signal, each of the tubes being defined by at least the following information cues: a block of reference pixels comprising reference texture information cues; start-of-tube and end-of-tube instants; and transition information cues. The method further includes processing the transition information cues and combining the information cues associated with the current blocks of at least two of the tubes overlapping in an overlap zone of the current image.