Abstract: Methods and devices are provided to encode points of a sphere onto an image by projecting them as a function of an isotropic region guided mapping operator and/or to decode pixels of an image onto a sphere by de-projected them according to the same parametrized mapping operator. A region of interest is determined on the sphere and the angular resolution of pixels of the image is modulated as a function of their distance to the reference pixel corresponding to the center of the region of interest. Chosen angular resolutions and size of the region of interest are associated with the image and encoded in a stream.

Abstract: A sequence of three-dimension scenes is encoded as a video by an encoder and transmitted to a decoder which retrieves the sequence of 3D scenes. Points of a 3D scene visible from a determined point of view are encoded as a color image in a first track of the stream in order to be decodable independently from other tracks of the stream. The color image is compatible with a three degrees of freedom rendering. Depth information and depth and color of residual points of the scene are encoded in separate tracks of the stream and are decoded only in case the decoder is configured to decode the scene for a volumetric rendering.

Abstract: Methods and devices for encoding, decoding and transmitting a three-dimensional scene initially represented as a multiplane image (MPI) are provided. Each layer of the MPI is split into patches based on the transparency component. Patches of a layer are grouped in a tile. The greater the depth of the layer, the greater the identifying number of the tile. When several tiles are packed in an atlas image, the same monotonic (i.e. ascending or descending) function according to depth applies to atlas numbers. At the decoding side, the current viewport to render is initially cleared and each decoded tile is sequentially blended over from the nearest one to the furthest due to the numbering of the set of atlases and tiles. Pixels of a patch under rendering are projected onto pixels of the viewport image according to the depth of the tile comprising the patch and metadata indicating the position of the patch in the layer of the MPI the patch has been clustered from.

Abstract: Methods, devices and data stream are provided for signaling and decoding information representative of restrictions of navigation in a volumetric video. The data stream comprises metadata associated to video data representative of the volumetric video. The metadata comprise data representative of a viewing bounding box, data representative of a curvilinear path in the 3D space of said volumetric video; and data representative of at least one viewing direction range associated with a point on the curvilinear path.

Abstract: A method and an apparatus for reconstructing a Computer-Generated Hologram from a multiple plane image are provided. Reconstructing the Computer-Generated Hologram comprises decoding data representative of at least one patch of at least one layer of the multiple plane image, the data comprising a first location for placing the patch in a first image of the multiple plane image, the first location being used for placing reconstructed content of the patch in a 3D scene, and determining for the at least one patch a second location for placing the patch in a second image, the second image being intended to be used for determining the Computer-Generated Hologram.

Abstract: Methods, devices and stream are disclosed to encode and decode a scene (such as a point cloud) in the context of a patch-based transmission of a volumetric video content. Attributes of points of the scene are projected onto patches. Every point has a geometry attribute. For other attributes, like transparency of displacement attribute, some points may have no value. According to the present principles, each attribute is encoded in a different atlas with its own layout. This allow to save pixel rate in memory of the renderer.

Abstract: Methods and devices for encoding and decoding data representative of a 3D scene are disclosed. A set of first patches is generated from a first MVD content acquired from a first region of the 3D scene. A patch is a part of one of the views of the MVD content. A set of second patches is generated from a second MVD content acquired from a second region of the 3D scene. An atlas packing first and second patches is generated and associated with metadata indicating, for a patch of the atlas, whether the patch is a first or a second patch At the decoding side, first patches are used for rendering the viewport image and second patches are used for pre-processing or post-processing the viewport image.

Abstract: Methods, devices and data stream are provided for signaling and decoding information representative of restrictions of navigation in a volumetric video. The data stream comprises metadata associated to video data representative of the volumetric video. The metadata comprise data representative of a viewing bounding box, data representative of a curvilinear path in the 3D space of said volumetric video; and data representative of at least one viewing direction range associated with a point on the curvilinear path.

Abstract: The present disclosure relates to method and apparatus for the estimation of an accurate multiplane image from a set of posed images. The accuracy of an MPI representation is measured by the performance of the views generated by it through inverse homography sampling and alpha compositing. A variable number of posed images at a possibly different resolution representative of scenes with arbitrary geometry are used as input of the system. A first level of three modules, possibly trained based on deep learning methods, is built for extracting view and scene features and color scores. Numerous levels of the same three modules may be built and organized in a structure where a level deals with down-scaled version of the posed images.

Abstract: Methods and devices for encoding and decoding data representative of a 3D scene are disclosed. A set of first patches is generated from a first MVD content acquired from a first region of the 3D scene. A patch is a part of one of the views of the MVD content. A set of second patches is generated from a second MVD content acquired from a second region of the 3D scene. An atlas packing first and second patches is generated and associated with metadata indicating, for a patch of the atlas, whether the patch is a first or a second patch At the decoding side, first patches are used for rendering the viewport image and second patches are used for pre-processing or post-processing the viewport image.

Abstract: A sequence of three-dimension scenes is encoded as a video by an encoder and transmitted to a decoder which retrieves the sequence of 3D scenes. Points of a 3D scene visible from a determined point of view are encoded as a color image in a first track of the stream in order to be decodable independently from other tracks of the stream. The color image is compatible with a three degrees of freedom rendering. Depth information and depth and color of residual points of the scene are encoded in separate tracks of the stream and are decoded only in case the decoder is configured to decode the scene for a volumetric rendering.

Abstract: An apparatus and a method are provided for image processing. In one embodiment, the method comprises accessing a plurality of images captured by at least a reference camera, wherein the images represent a plurality of views corresponding to said same scene. A plurality of plane sweep volume (PSV) slices are then generated from said images and computing for each slice a flow map from at least the reference camera calibration parameter and this flow map a previous slice of the plane sweep volume is generated.

Abstract: A patch-based atlas format in intra-periods of varying length is used to encode a volumetric video. A first atlas layout is built for a first sequence of 3D scenes. The number of 3D scenes in the sequence is chosen to fit the size of a Group of Pictures of the codec. A second sequence is iteratively set up by appending the next 3D scene of the sequence to encode while the number of patches of the layout built for this iterative second sequence is lower than or equal to the number of patches of the first layout. When iterations end, one of the layouts is selected to generate every atlas of the group. In such a way, size of metadata is decreased, and compression is enhanced.

Abstract: Methods, devices and data streams are proposed to encode, transport and decode 3D volumetric videos. The embodiments encompass the signaling of non-Lambertian patches together with their light reflection properties, so as to enable a ray-tracing based rendering engine to synthesize visually realistic virtual views with respect to light effects. A retro-compatible solution enabling conventional rendering engines to render such described 3D scene but without the advanced light effects is also described.

Abstract: Methods and devices for encoding and decoding 3D scenes of an immersive video are disclosed with the related data stream. Taking advantage of the fact that parts of the 3D scene does not change from one frame of the video to another, even when the cameras move and/or the lighting condition change, dynamic and static parts of the 3D scene are encoded in different atlases. In an embodiment, static patch atlases are repeated between two updates. In another embodiment, only updates are encoded and transmitted. The decoder maintains a memory associating entity of the 3D scene with a set of static patches that is updated with instructions linked to update static patch atlases. At each presentation time the static part of the 3D scene to decode is obtained from the memory.

Abstract: Methods and devices for generating a multiplane image from a representation of a 3D scene are disclosed. Given a representation of the 3D scene, for example as a multiview image, a first MPI is generated by a convolutional neural network trained for generating a MPI according to a provided sampling of the depths of the 3D scene. The presence of objects in different layers, that is the complementary of the accumulated transparency of layers, is analyzed to resample the sampling of layers' depth. The new sampling is used by the CNN to generate a new MPI from a representation of the same 3D scene.

Abstract: Methods, devices and stream are disclosed for encoding, transporting and decoding a 3D scene prepared to be viewed from the inside of a viewing zone. A central view comprising texture and depth information is encoded by projected points of the 3D scene visible from a central point of view onto an image plane. Patches are generated to encode small parts of the 3D scene not visible from the central point of view. At the rendering, a viewport image is generated for the current point of view. Holes, that is dis-occluded areas, of the viewport are filled using a patch based inpainting algorithm adapted to take the patches, warped according to the rotation and translation between virtual camera used for capturing the patch and the current virtual camera.

Abstract: A method for encoding a volumetric video content representative of a 3D scene is disclosed. The method comprises obtaining a reference viewing box and an intermediate viewing box defined within the 3D scene. For the reference viewing bounding box, the volumetric video reference subcontent is encoded as a central image and peripheral patches for parallax. For the intermediate viewing bounding box, the volumetric video intermediate sub-content is encoded as intermediate central patches which are differences between the intermediate central image and the reference central image.

Abstract: Methods, devices and video data encoding a volumetric 3D scene are disclosed. The user is allowed to modify values of rendering effects for some objects of the 3D scene in ranges provided by the content creator or the broadcaster. Metadata describing the possibilities of modifications, the concerned objects and authorized ranges of values are associated with the payload content. On the decoding side, according to these metadata an interface is provided to the user for modifying the values in the authorized ranges.

Abstract: A method and a device for generating a data stream representative of a volumetric video generated from a sequence of multi-plane images are disclosed. A quantization law depending on an angular resolution used to generate patches from the multi-plane images is set up. For each intra-periods of the frame sequence, patches are generated for a given angular resolution. If generated patches do not fit in atlas images of a target size, the angular resolution is decreased and patches are generated again according to this new angular resolution.