Orange

France Telecom

B-com

Joël Jung

Guillaume Laroche

Patrick Boissonade

Pavel Nikitin

Jean Marc Thiesse

Jean-Marc Thiesse

Patrick Garus

Gordon Clare

Félix Henry

Stéphane Pateux

Bappaditya Ray

Kartik Viswanathan

Marco Cagnazzo

Marc Baillavoine

Loïc Baroux

Marc Antonini

Julien Le Tanou

Dang Khoa Vo Nguyen

Marc Ballavoine

Elie Gabriel Mora

Antoine Dricot

Béatrice Pesquet-Popescu

Charlène Mouton

Methods for coding and decoding a coded data stream representative of a multi-view video. The coded data stream includes data representative of at least one atlas, which corresponds to an image having at least one patch. The at least one patch corresponds to a set of pixels extracted from at least one component of a view of the multi-view video, the view not being coded in the coded data stream. The method for decoding includes decoding, from the coded data stream, the at least one atlas, including decoding the at least one patch, determining, for the decoded patch, whether a transformation, and which transformation, must be applied to the decoded patch, the transformation belonging to the group including at least one oversampling of the patch or a modification of the pixel values of the patch, and applying the determined transformation to the decoded patch.

Methods and devices for coding and decoding a multi-view video sequence

A method for processing multi-view video data including, for at least one block of an image of a view encoded in an encoded data stream representing the multi-view video, obtaining at least one information item, which specifies a mode for obtaining a synthesis data item, from among first and second obtaining modes. The synthesis data item is used to synthesize at least one image of an intermediate view of the multi-view video, the intermediate view not being encoded in the encoded data stream. The first obtaining mode involves decoding an information item representing the synthesis data item from the encoded data stream, the second obtaining mode involves obtaining the synthesis data item from at least the reconstructed encoded image. At least one part of an image of the intermediate view is synthesised from at least the reconstructed encoded image and the synthesis data item obtained by the specified mode.

Method and device for processing multi-view video data with synthesis data

A method and a device for processing multi-view video data. The multi-view video data includes at least one part of a decoded image of at least one view of the multi-view video, from an encoded data stream representative of the multi-view video. At least one item of data, referred to as synthesis data, is obtained from at least the one part of the decoded image, and at least one image of an intermediate view of the multi-view video not encoded in the encoded data stream is synthesized from at least the one part of the decoded image and from the synthesis data obtained.

Method and device for processing multi-view video data

A method for decoding a data stream representing a multi-view video, including coded data representative of at least one sub-image, including texture data and depth data associated with the texture data, the sub-image including at least one zone, referred to as a useful zone, for generating an image of a view. An indicator is decoded, indicating whether the sub-image is coded according to a first method or a second method. When the indicator indicates that the sub-image is coded according to the first method, a binary map is decoded indicating for at least one pixel of the sub-image whether the pixel belongs to the useful zone. When the indicator indicates that the sub-image is coded according to the second method, the texture and depth data of the sub-image are decoded. The depth data of the sub-image for the pixels situated outside the useful zone includes a decoded depth value.

Synthesis of an image of a view from data of a multi-view video. The synthesis includes an image processing phase as follows: generating image synthesis data from texture data of at least one image of a view of the multi-view video; calculating an image of a synthesised view from the generated synthesis data and at least one image of a view of the multi-view video; analysing the image of the synthesised view relative to a synthesis performance criterion; if the criterion is met, delivering the image of the synthesised view; and if not, iterating the processing phase. The calculation of an image of a synthesised view at a current iteration includes modifying, based on synthesis data generated in the current iteration, an image of the synthesised view calculated during a processing phase preceding the current iteration.

Iterative synthesis of views from data of a multi-view video

A method for decoding a data stream representing a multi-view video, including coded data representative of at least one sub-image, including texture data and depth data associated with the texture data, the sub-image including at least one zone, referred to as a useful zone, for generating an image of a view. An indicator is decoded, indicating whether the sub-image is coded according to a first method or a second method. When the indicator indicates that the sub-image is coded according to the first method, a binary map is decoded indicating for at least one pixel of the sub-image whether the pixel belongs to the useful zone. The texture and depth data of the sub-image are decoded, when the indicator indicates that the sub-image is coded according to the second method, the depth data of the sub-image for the pixels situated outside the useful zone including a decoded depth value.

A method for synthesizing an image of a view from images of N (N&#x3e;2), implemented by an image synthesis device. The method includes: projecting, to a position corresponding to the image of the view to be synthesized, N depth maps associated with the N views, respectively; for at least one given pixel of at least one projected depth map, for which a depth value has been associated on completion of projection, modifying the depth value of the at least one given pixel if an item of reliability information associated with the depth value is at a certain value, the modification using the depth value of a pixel whose position corresponds to that of the at least one given pixel, in at least one other projected depth map, which generates at least one modified projected depth map.

View synthesis

An encoding device and method are provided for encoding at least one image split into partitions. The method implements, for a current partition to be encoded, steps of: selecting at least one causal partition already encoded and then decoded; calculating at least one optimal encoding parameter associated with the selected causal partition, according to a predetermined criterion of encoding performance, by comparing a plurality of encoding parameters applied to the selected causal partition; and encoding the current partition by using the calculated optimum encoding parameter.

Method for encoding and decoding images, device for encoding and decoding images and corresponding computer programs

A method and apparatus are provided for processing movement information relating to a regular image of a sequence of images. The method includes: a step of building a list including at least one expected piece of movement information and at least one unexpected piece of movement information; a first step of associating expected movement information with movement information according to a first rule for optimizing the cost of encoding the movement information to be encoded; a second step of associating each unexpected piece of movement information not associated during the first association step with movement information to be encoded, identified among the pieces of movement information of the list, according to a second rule which aims to ensure that each piece of movement information is associated with a single piece of movement information to be encoded.

Method for processing a motion information item, encoding and decoding methods, corresponding devices, signal and computer program

A method is provided for decoding a data stream representative of an image or of a sequence of images, the stream comprising data representative of at least one portion of one of the images, the method implementing a step of predicting a motion vector of a partition of a current image portion, with respect to a reference causal zone which has been partitioned according to a mode of coding determined for the zone. The prediction step comprises, in relation to said current partition: partitioning anew at least one portion of the reference causal zone into a plurality of reference partitions, determining motion vectors respectively associated with reference partitions obtained subsequent to the new partitioning, determining a predictor motion vector on the basis of said determined motion vectors, and predicting the motion vector of said current partition on the basis of said determined predictor motion vector.

Prediction of images by repartitioning of a portion of reference causal zone, coding and decoding using such a prediction

A method and apparatus are provided for predicting a movement vector of a current image partition in relation to a movement vector of a reference partition having the same form as the current image partition and belonging to a reference image (IN-) which is different from the current image and has been pre-cut, following encoding and subsequent decoding, into a plurality of n partitions. One such method includes, when the reference partition covers a set of k reference partitions from among the plurality of n reference image partitions, with k&#x2266;n, determining the movement vector of the current image partition from a function of at least one reference movement vector belonging to a set of k reference movement vectors associated respectively with k covered reference partitions.

Prediction of a movement vector of a current image partition pointing to a reference zone that covers several reference image partitions and encoding and decoding using one such prediction

A method and device relate to coding an image split up into partitions, which comprises the selection of at least one mode of coding and of its associated coding information items, from among items placed in competition, the prediction of the data of a current partition, the determination of residual data. Calculation of the value of a function representative of said residual data are performed, then the comparison of said calculated value with a value selected as value of competition index from among the associated values. If the values are equal, said signal transmitted comprises said residual data and said associated coding information items. If not, the residual data determined are modified so that the value of the function representative of the residual data is equal to the selected value of competition index, the signal transmitted comprising the modified residual data, excluding the selected value of competition index.

Methods and devices for image encoding and decoding, and corresponding computer programs

The present invention relates to a method of transmitting at least one current image portion, wherein the method comprises selecting a coding function from a finite set of coding functions by applying at least one choice function of a first type, said choice function or functions of said first type using already-decoded image data, coding the current image portion using the selected coding function, sending the coded image portion to a decoder, and sending to said decoder information describing the choice function or functions of said first type. The invention also relates to the corresponding decoding method.

Decoding function selection distributed to the decoder

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.

Methods for encoding and decoding a signal of images, corresponding encoding and decoding devices, signal and computer programs

A method is provided of coding an image or a sequence of images generating a stream of data comprising data representative of at least one group of pixels in one of said images. Such a method comprises the steps of: selecting, for a group of pixels to be coded, an initial partition of predetermined linear form, slicing said group of pixels to be coded according to said selected initial partition, propagating said initial partition selected in said group of pixels to be coded, until the latter is sliced in its entirety into a plurality of partitions of predetermined form, selecting, for said sliced group of pixels, a predetermined order of traversal of said partitions, predicting and coding said partitions one after the other, according to said selected order of traversal.

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Le Mesnil Saint Denis, France

Joël Jung