France Telecom

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Telediffusion De France

France Telecom Sa

Telediffusion De France S.a.

France Telecom and Telediffusion De France

Nathalie Laurent-Chatenet

Henri Sanson

Alexandre Buisson

Patrick M Lechat

Laurent Demaret

Pierre Alliez

Guillaume Robert

Patrick Lechat

The invention concerns a method for coding images using selectively at least two image coding modes, each optimising compression of at least a video sequence image on the basis of different optimisation criteria.

Image coding and decoding method, corresponding devices and applications

The invention relates to motion estimation and compensation between two given images represented by a polygonal mesh. It provides a solution to the problems of crowding and uncovering of mesh units when the mesh is shifted. More specifically, the invention relates to a method for the encoding of a mesh that represents an image of a moving sequence. According to the invention, such a mesh is larger in size than the image.

Motion estimator for coding and decoding image sequences

The invention concerns a method for encoding at least a source image using a hierarchical mesh defining at least two nested spaces corresponding each to a decomposition level of said meshing, which consists, at least at a decomposition level n (except the first decomposition level), in delivering only image coefficients expressed in a base of functions defined in a space orthogonal to the space corresponding to the preceding decomposition level n&#x2212;1, said functions being selected so that said image coefficients enable to optimize for said decomposition level n the data already transmitted for the preceding decomposition level n&#x2212;1, so as to produce a reconstructed image, representing said source image, with optimized restoration quality for said decomposition level n.

Methods and devices for encoding and decoding images using nested meshes, programme, signal and corresponding uses

The invention concerns a method for constructing at least an image interpolated between a preceding image and a following image of an animated sequence. The invention is characterised in that the method takes into account data concerning the presence of at least an occlusion zone in said preceding image and/or in said following image, called occlusion data.

Method for calculating an image interpolated between two images of a video sequence

The invention concerns the refinement of a triangular mesh representing a three-dimensional object (3D), said mesh consisting of an arrangement of vertices and triangular surfaces, each defined by three references to the vertices which it links, and having three edges each linking two of said vertices. The invention is characterized in that said method comprises a step which consists in selecting at least a region of interest, said mesh refinement being carried out locally on at least one region of interest.

Refinement of a triangular mesh representing a three-dimensional object

The invention relates to a method for coding an image that is to be coded, characterized in that said method comprises the following steps: definition of a hierarchical mesh structure having at least two levels of interconnected meshing formed from mesh units which are defined by peaks; determination, for each of said mesh units, of information concerning an error between the image which is to be coded and an interpolated image obtained from the peaks of the mesh units pertaining to the level of the meshing of the mesh unit in question; termination () of the refinement of mesh units having error information below a first predetermined threshold; implementation of a specific coding () for the mesh units having error information above a second predetermined threshold; continuation () of the refinement of mesh units having error information above the first predetermined threshold and below the second predetermined threshold.

Variable transformation hierarchical image coding

An image coding method for a domain corresponding to at least one portion of an image. A minimal triangular partition covering the domain is defined. A square matrix is associated with each of the source triangles by a first reversible transformation so that each matrix represents a specific source triangle. A second reversible decorrelation transformation is applied to each square matrix, resulting in transformed matrixes. The method may be used in isolation, or as a supplement to another coding of the hierarchic type. A corresponding decoding method is also provided.

Image coding/decoding method

The invention relates to a method for estimating the motion between two digital images and to the use of this method for coding images. The aim of the method is to eliminate the disturbances caused by the mesh being overturned during the motion estimation process. According to the invention, the method consists of carrying out a first motion estimation in order to identify the faulty mesh, i.e. the mesh that is overturning or is overlapping after the displacement vectors have been applied; then carrying out a second motion estimation, excluding at least said faulty mesh, in order to minimize prediction error on the remaining mesh of the model.

Method for estimating the motion between two digital images with management of mesh overturning and corresponding coding method

A method for encoding a digital image for producing a bit stream representing the image, the bit stream length depending on the quality of the desired representation, consisting in: a) defining, on the domain of the image to be encoded, a hierarchical meshing comprising a plurality of nested meshes whereof the mesh peaks are the image pixels; b) determining for each mesh of the hierarchical meshing, a brightness variation between the image to be encoded and an interpolated image obtained from the nested meshing peaks whereto pertains the mesh concerned; and c) inserting in the bit stream position, brightness and chrominance values of the peaks of meshes whereof the brightness variation is higher than a threshold variation useful for encoding fixed or animated images with speed reduction.

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Vignoc, France

Nathalie Laurent-Chatenet