Abstract: A method for coding or decoding pixel blocks is disclosed. The number of usable modes at the coder and at the decoder is limited to a subset of the set of possible coding modes and the content of this subset is regularly adapted to the content of the images of the sequence. Thus, the coder or decoder always only has a reduced number q<n of coding modes available, called available coding modes, to code or decode the current pixel block but this subset of q coding modes is regularly modified according to the pixel blocks already coded or decoded.

Abstract: A method for decoding a stream of coded data representative of a sequence of images is disclosed. The decoding method comprises: determining a prediction block, calculating the average of said prediction block, reconstructing, from said stream, a DC coefficient and AC coefficients relating to said current block, calculating an average of said current block from said average of said prediction block and said DC coefficient, calculating a weighted prediction parameter as being the ratio of the average of said current block and the average of said prediction block, transforming a block of coefficients comprising a null value as DC coefficient and said reconstructed AC coefficients into a residual block, reconstructing the current block by merging said residual block and said prediction block weighted by said weighted prediction parameter. A method for coding is further disclosed.

Abstract: The invention relates to a method for generating for at least one block of pixels of a picture of a sequence of interlaced pictures at least one motion predictor and at least one texture predictor from motion data, respectively texture data, associated with the pictures of a sequence of low resolution interlaced pictures.

Abstract: The invention relates to a method for generating for at least one block of pixels of a picture of a sequence of interlaced pictures at least one motion predictor and at least one texture predictor from motion data, respectively texture data, associated with the pictures of a sequence of low resolution interlaced pictures.

Abstract: The process comprising splitting of an image into blocks, intra coding of a current block using spatial prediction based on a matching pursuit algorithm selecting, from a dictionary of atoms, the atom the most correlated with a causal neighborhood of the current block, is characterized in that it performs the following steps: — determination of the two dimensional shift between the causal neighborhood and the selected atom, — generation of at least, a new phased atom taking into account the values of the two dimensional spatial shift, — use of this new atom for intra prediction, according to the matching pursuit algorithm, if better correlated than the selected one. Application to video data compression.

Abstract: The invention is related to a method for determining a filter for interpolating one or more pixels comprised in a frame. The proposed method comprises the step of determining the filter based on other pixels in the remainder of the frame wherein a motion vector associated with said pixels has at least one motion parameter in common with another motion vector associated with said other pixels and the filter is determined such that a quality of an interpolation of said other pixels, said interpolation being determined by help of said determined filter, reaches or exceeds the quality of any other interpolation of said other pixels determinable by help of one of different filter candidates comprised in a filter candidate set. In determining the filter solely on different other pixels of the same frame, said method for determining a filter for interpolation allows for realization of a single pass encoding framework.

Abstract: A method for coding a current block is disclosed. The method comprises an iterative step of decomposition into atoms of a first dictionary of a vector of data comprising at least reconstructed image data associated with pixels situated in a causal neighboring area of a current block. At each iteration, the step of decomposition into atoms comprises the following steps for: selecting a first atom in the first dictionary of atoms, applying a phase correlation between a patch associated with the first atom and a current residue vector, when the first atom is a textured atom, extracting from the patch at least the part most correlated with the residue vector, the extracted part forming a second atom, selecting from among the first atom and the second atom, the atom most correlated with the current residue vector, and updating the residue vector according to the selected atom.

Abstract: A method for coding a picture portion of a picure of a video sequence is disclosed, at least one picture of the video sequence being a key picture. The method comprises the following steps: a) calculate a saliency map of the key picture, b) estimate for the picture portion to be coded, at least one motion vector pointing towards a portion of the key picture, c) motion compensate at least one portion of the saliency map using an estimated motion vector to obtain, for said picture portion, at least one portion of the predicted saliency map, and d) code the picture portion according to the saliency level of the portion of the predicted saliency map. The invention also relates to a method for decoding a binary stream, a coder able to code pictures of a video sequence and a decoder of a binary stream.

Abstract: A method for arithmetic coding of symbols in a stream is described. The method comprises the following steps: coding a current symbol with a current probability model, and updating the current probability model according to the coding of the current symbol. selecting the current probability model in a set of at least two probability models according to a coding cost criterion, and coding an identifier of the selected probability model.

Abstract: The invention proposes a method for reconstructing a self-similar textured region of an image. Said method comprises determining pixels of a part of the self-similar textured region by copying sample pixels from a sample part of the self-similar textured region, the sample pixels being selected using a neighbourhood matching, wherein a size of neighbourhoods used for matching is selected based on an analysis of descriptors computed from coefficients of OCT transform of differently sized blocks of the sample part. The analysis of descriptors computed from coefficients of DCT transform of differently sized blocks of the sample part allows for determining the neighbourhood size close to a feature size of the texture.

Abstract: A method for coding a current block using a parametric motion model whose parameters are defined from the motion data of the causal neighbourhood is disclosed. Specifically, the method for coding the current block comprises the following steps: determine a prediction block of the current block from a motion model defined by a set of parameters, the model associating a motion vector pointing at a pixel of a prediction block with each pixel of the current block. calculate a residual block between the current block and the prediction block, and code the residual block. According to the invention, the parameters of the motion model are determined from the motion data associated with the causal neighbourhood blocks of the current block. Therefore, they can be deducted from parts of images already coded and do not need to be incorporated in the image data stream.

Abstract: A method for coding a block of pixels is disclosed. The method for coding comprises: calculating a block of residues from the pixel block and a prediction block, transforming the block of residues into a block of coefficients with a transform defined by a set of basis functions, coding the block of coefficients, The method comprises, before the transformation step, a step for rephasing basis functions from residues calculated in a causal neighbourhood of the pixel block. The transformation step uses the rephased basis functions.

Abstract: A method for coding a block of pixels is described. The coding method comprises: determining a prediction block for the pixel block from a motion vector; calculating a residue between the pixel block and the prediction block; and code the residue. The determination of the prediction block comprises the following steps: determining an intermediate prediction block of size strictly greater than the size of the pixel block; transforming the intermediate prediction block into a first block transformed with a first transform; and transforming the first transformed block into a second block transformed with a second transform of inverse the first transform whose basis functions are shifted by at least a part of each component of the motion vector, the prediction block being extracted from the second transformed block.

Abstract: A method for decoding a stream of coded data representative of a sequence of images divided into blocks is described. It comprises the following steps for a current block: reconstructing a residual block of residual data from the decoding of a first part of the coded stream of data relating to the current block, determining a prediction block, and reconstructing the current block by merging the residual block and the prediction block, According to the invention, the decoding method comprises in addition a step of reorganization of residual data in the residual block before the reconstruction of the current block according to the content of the prediction block. The invention also relates to a method for coding.

Abstract: A method for generating for at least one block of pixels of a picture of a sequence of progressive pictures at least one motion predictor and at least one texture predictor from motion data, respectively texture data, associated with the pictures of a sequence of low resolution interlaced pictures.

Abstract: The invention is made in the field of image block encoding and reconstruction. A method for reconstructing a current block of an image is described, the current block being encoded using predictive encoding of segments resulting from geometry adaptive block partitioning of said current block. After decoding encoded data comprising at least one flag and motion vectors, wherein blocks referenced by the motion vectors are used for prediction of segments of the current block, the at least one flag and an encoding order of the motion vectors in the encoded data is used for determining which of the referenced blocks exhibits a geometry that matches the geometry of the current block and for determining a segment of the determined block, wherein prior to determining the segment, the determined block is geometry adaptive block partitioned into segments from which the segment is determined for predicting one of the segments of the current block.

Abstract: A method for decoding a video picture comprising coded structured regions and textured regions is disclosed. A reference texture patch is constituted of a part or of blocks of the structured region found around the textured region and the pixels of the textured region are synthesized sequentially according to a spiral type scanning around the textured region, the causal area being found inside the reference texture patch at least for the first round of synthesis.

Abstract: A method for coding a current block is disclosed. The method comprises: determining a prediction block from the current block, determining a residue block by extracting from the current block the prediction block, and coding the residue block. The prediction block from the current block is determined according to the following steps for: determining an initial prediction block from motion data and at least one reference image previously coded and reconstructed, applying an atomic decomposition method on a vector of data Ycp, comprising the image data of neighbouring blocks of the current block previously coded and reconstructed and the data of the initial prediction block, and extracting from the decomposed vector the data corresponding to the current block, the extracted data forming the prediction block.

Abstract: A method for coding a block of pixels is disclosed. The method comprises the following steps: determining, for each pixel of the current block, a prediction pixel by thresholding, with a current threshold value, of coefficients resulting from a transformation applied on a window covering at least the pixel of the current block and by inverse transformation applied to the thresholded coefficients, extracting from the current block a prediction block formed of prediction pixels to generate a residue block, and coding said residue block, According to the invention, the current threshold value is determined or coded from neighbouring reconstructed pixels of the current block.

Abstract: A method for coding a current block is disclosed. The method comprises an iterative step of decomposition into atoms of a first dictionary of a vector of data comprising at least reconstructed image data associated with pixels situated in a causal neighbouring area of a current block. At each iteration, the step of decomposition into atoms comprises the following steps for: selecting a first atom in the first dictionary of atoms, applying a phase correlation between a patch associated with the first atom and a current residue vector, when the first atom is a textured atom, extracting from the patch at least the part most correlated with the residue vector, the extracted part forming a second atom, selecting from among the first atom and the second atom, the atom most correlated with the current residue vector, and updating the residue vector according to the selected atom.