Abstract: A method for reducing the parameters defining an acquired light field ray which enables only the colour associated with the light field ray to be stored instead of 4 light field co-ordinates (x,y,i,j) and its associated colour.

Abstract: There are several types of plenoptic devices having their proprietary file format. At present there is no standard supporting the acquisition and transmission of multidimensional information for an exhaustive over-view of the different parameters upon which a light-field depends. As such acquired light-field data for different cameras have a diversity of formats. The notion of pixel beam, which represents a volume occupied by a set of rays of light in an object space of an optical system of a camera is thus introduced. The method according to the invention enables to provide data representative of a collection of pixel beams describing a first optical system that is agnostic since these data are obtained by imaging the collection of pixel beams through a second optical system. Such data representative of a collection of pixel beams enable the generation of parametrized output images from which post-processing.

Abstract: The disclosure concerns a method for filtering spurious pixels in a depth-map. It is important to filter a depth-map to remove the spurious pixels. One issue when filtering spurious pixels, is to remove them while preserving the boundaries of the real details of the depth-map. A known approach to filter spurious pixels is to use a bi-lateral filter. However, the bi-lateral filter is not efficient to remove the spurious pixels. The proposed solution enables to remove spurious pixels in a depth-map while preserving the sharp edges of the depth-map and smoothing faint details or noise.

Abstract: A method for encoding a plenoptic image divided into blocks is disclosed. The method comprises: —encoding (S120) a block in a central region of the plenoptic image, called central block, without spatial prediction; and—predictively encoding (S130) blocks immediately surrounding said central block by spatially interleaving spatial unidirectional prediction and spatial bi-directional prediction.

Abstract: The invention consists in a method of and a device for temporal filtering of disparity maps of n different frames, each map indicating the disparity of pixels of 3D images comprising the steps of marking the stationary pixels and the non stationary pixels and implementing temporal filter for stationary pixels, detecting limitations for temporal filtering corresponding to a variation of moving pixels above a determined threshold value and automatically de-activating the temporal filters as response to the detected limitations for temporal filtering.

Abstract: The present disclosure generally relates to a method for reducing the coding artefact of at least one pixel of a view (170) belonging to a matrix of views (17) obtained from light-field data associated with a scene. According to present disclosure, the method is implemented by a processor and comprises for each said at least one pixel: —from said matrix of views (17), obtaining (51) at least one epipolar plane image (EPI) associated with said pixel, —applying (52) an artefact filtering on pixels of said epipolar plane image (EPI), —redistributing (53) the filtered pixels of the epipolar plane image in the matrix of views (17).

Abstract: There are several types of plenoptic devices and camera arrays available on the market, and all these light field acquisition devices have their proprietary file format. However, there is no standard supporting the acquisition and transmission of multi-dimensional information. It is interesting to obtain information related to a correspondence between pixels of a sensor of said optical acquisition system and an object space of said optical acquisition system. Indeed, knowing which portion of the object space of an optical acquisition system a pixel belonging to the sensor of said optical acquisition system is sensing enables the improvement of signal processing operations. The notion of pixel beam, which represents a volume occupied by a set of rays of light in an object space of an optical system of a camera is thus introduce.

Abstract: There are several types of plenoptic devices and camera arrays available on the market, and all these light field acquisition devices have their proprietary file format. However, there is no standard supporting the acquisition and transmission of multi-dimensional information. It is interesting to obtain information related to a correspondence between pixels of a sensor of said optical acquisition system and an object space of said optical acquisition system. Indeed, knowing which portion of the object space of an optical acquisition system a pixel belonging to the sensor of said optical acquisition system is sensing enables the improvement of signal processing operations. The notion of pixel beam, which represents a volume occupied by a set of rays of light in an object space of an optical system of a camera is thus introduce.

Abstract: A method for encoding a current focal stack is disclosed that comprises a set of images focused at a different focalization distance from one image to another. According to present disclosure, the method comprises: —encoding (31) information representing an image of the current focal stack, the image being selected in said current focal stack according to an image sharpness criterion, and reconstructing the image into a reconstructed image; —encoding (32) at least another image of the current focal stack by prediction from at least the reconstructed image.

Abstract: In an image processing method to display a stereoscopic image on a target screen, a disparity information (200) is associated with the stereoscopic image and is adapted for the display of the stereoscopic image on an original screen, the size of the original screen being different from the size of the target screen, the stereoscopic image comprising a first image (20) and a second image (21). In order to optimize the disparity of the stereoscopic image, the method comprises selecting a part of said first image according to at least one property associated with the first image; calculating a target disparity information associated with the selected part of the image according to the viewing conditions associated with the target screen and the original disparity information associated with the selected part of the first image.

Abstract: A method for modelling an imaging device including an image sensor and an optical system is disclosed. The optical system has an aperture iris diaphragm defining an entrance pupil of the optical system. For a given configuration of the imaging device the method includes estimating a set of characteristic intrinsic parameters of the imaging device, in which a first intrinsic parameter is representative of a distance between the image plane and a sensor conjugated plane conjugated to the image sensor with respect to the optical system; a second intrinsic parameter is representative of a distance between the sensor conjugated plane and the entrance pupil and a third intrinsic parameter is representative of a magnification of the optical system; determining first and second modelling data respectively as a function of the first and third intrinsic parameters and second and third intrinsic parameters; and establishing a model of the imaging device as a function of the second and third modelling data.

Abstract: There are several types of plenoptic devices having a proprietary file format. At present, there is no standard supporting the acquisition and transmission of multi-dimensional information for an exhaustive over-view of the different parameters upon which a light-field depends. As such, acquired light-field data for different cameras have a diversity of formats. The notion of pixel beam, which represents a volume occupied by a set of rays of light in an object space of an optical system of a camera is introduced. The method according to the invention enables to provide data representative of a bokeh associated to a pixel beam. Such data representative of bokeh associated to a pixel beam enables the displaying of an image with good bokeh properties.

Abstract: A method of providing metadata for captured light field data, the method comprising providing a data format aggregating metadata describing characteristics of at least one of: a light field camera used to capture the light field data, a matrix of views derived from the light field data, and a focal stack derived from the light field data.

Abstract: A method is proposed for determining missing values in a depth map corresponding to a pixel matrix representative of an image. The method comprises: scanning at least one column or row of said depth map; obtaining, for at least one pixel with an invalid depth value being scanned an information representative of the depth of first and second valid neighbor pixels; computing a transposed depth map, corresponding to the depth map of a transposed matrix of the pixel matrix; scanning at least one column or row of said transposed depth map including said invalid pixel; obtaining, for said invalid pixel an information representative of the depth of third and fourth valid neighbor pixels; determining, for said at least one invalid pixel, a depth value based on the information representative of the depth of said first, second, third and fourth valid neighbor pixels.

Abstract: A method for estimating the position, on a sensor of a light-field acquisition device of a projection of a chief ray, corresponding to an optical axis of the light-field acquisition device is described. The method includes determining a coarse estimate of the position of the chief ray projection through shape-matching of the micro-images formed on the sensor by cross-correlation computation and optionally refining the coarse estimate by illumination fall-off analysis of the raw image formed on the sensor.

Abstract: A method for encoding a matrix of views obtained from light-field data is disclosed. The method includes obtaining information representative of a type of encoding and encoding such information, wherein the type of encoding corresponding to an epipolar plane image encoding using at least one part of epipolar plane image, or said type of encoding corresponding to a view by view encoding according to a views' encoding order, and encoding the group of views in said data stream responsive to said information representative of a type of encoding, wherein, in the case where said type of encoding is an epipolar plane image encoding. The group of views is encoded by obtaining at least one part of an epipolar plane image, and encoding said at least one part of an epipolar plane image.

Abstract: A method for estimating occlusion in a virtual environment comprising at least two objects and observed from a viewpoint. Thereafter, a second item of information representative of the distance separating a second fragment of a second object from the viewpoint according to an observation direction is computed; the second item of information is compared with a first item of information representative of the distance separating a first fragment of a first object from the viewpoint according to the observation direction and is stored in a first buffer memory. If the second item of information is less than the first item of information, then a third item of information representative of attributes associated with the second fragment is estimated, the second item of information is stored in a second buffer memory and of the third item of information is stored in a third buffer memory.

Abstract: The following steps are carried out in the inventive method: estimation of movement between a current moment corresponding to the current image and a reference moment corresponding to a reference image in order to provide a movement vector, an entropic coding for a high spatial frequency signal relating in the current image, taking into account a temporal context based on the estimation of a movement, one of the parameters used to calculate the temporal context being the parity of a component of the movement vector. Applications are related to video compression with temporal prediction.

Abstract: A method of performing depth estimation, the method comprising: estimating, at a higher spatial resolution of images, a global disparity map based on disparity between corresponding pixels of a stereo disparity map obtained from images forming a stereo image set associated with a passive depth estimation technique and an active depth map associated with an active depth estimation technique, wherein the disparity is estimated within a restricted range determined based on a disparity previously estimated between a stereo disparity map and an active depth map corresponding to a lower spatial resolution of the said images and map.

Abstract: The invention relates to a method for modeling a scene from a plurality of maps representative of depth, each map representative of depth being associated with a view of the said scene according to a particular viewpoint, To optimize the fidelity and precision of the scene modeling, the method comprises the following steps: generating, for each map representative of depth, a surface representative of the said depth map in world space; estimating a volume bounding all surfaces generated, the said bounding volume being discretised into a plurality of voxels; associating attributes representative of transparency with the said voxels of the bounding volume; and generating a resulting surface according to the attributes representative of transparency associated with the said voxels. The invention also relates to a device for processing the data representative of the corresponding depth.