Abstract: The disclosure relates to method for storing and transmitting sparse matrices in compact way. When storing and manipulating sparse matrices on a device, it is beneficial and often necessary to use specialized algorithms and data structures that take advantage of the sparse structure of the matrix. The trade-off is that accessing the individual elements becomes more complex and additional structures are needed to be able to recover the original matrix unambiguously. The method according to an embodiment includes storing indexes enabling the position in the matrix of non-null elements to be determined in an ordered way, so as to limit the amount of information to be encoded, and thus reduce the amount of data to be transmitted. The encoded information is sufficient for enabling the reconstruction of the matrix on a receiver.

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: A method for obtaining, for at least one pixel of an image sensor comprised in an optical device, parameters defining a pixel beam is described. The method is remarkable in that it includes determining a direction of a chief ray associated with at least one pixel of the image sensor from the features of an optical system associated with the optical device, determining a set of pixels formed in a screen of a display device, the set of pixels comprising at least one pixel close to a point corresponding to an intersection of the chief ray and the screen, and the set of pixels comprising only pixels which are detected by the at least one pixel of the image sensor, when they are illuminated.

Abstract: The present disclosure relates to the transmission of sets of data and metadata and more particularly to the transmission of light-field contents. Light-field data take up large amounts of storage space which makes storage cumbersome and processing less efficient. In addition, light-field acquisition devices are extremely heterogeneous and each camera has its own proprietary file format. Since acquired light-field data from different cameras have a diversity of formats a complex processing is induced on the receiver side. To this end, it is proposed a method for encoding a signal representative of a light-field content in which the parameters representing the rays of light sensed by the different pixels of the sensor are mapped on the sensor. A second set of encoded parameters are used to reconstruct the light-field content from the parameters representing the rays of light sensed by the different pixels of the sensor.

Abstract: An electronic imaging device having a plurality of photosensitive cells arranged in an array to form a frame region, the frame region being composed of a plurality of frame sub-regions each frame sub-region corresponding to a sub-set of photosensitive cells, the device comprising an array controller configured to expose each of said frame sub-regions during an exposure duration wherein the exposure of at least some of said frame sub-regions occurs at different times during a total time of exposure of the frame region, a flash unit for illuminating a scene to be imaged during a flash time duration an activator for activating the flash unit to illuminate the scene to be imaged at a flash time delay determined in dependence upon said exposure duration of a frame sub region and the flash time duration; an image data acquisition unit for acquiring a set of frames of the scene wherein the time of occurrence of a flash event within a frame shifts temporally from frame to frame; and an image reconstruction unit for c

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: The disclosure addresses the vignetting effect caused on an image captured by lightfield camera. A method to compensate for the vignetting effect for a lightfield camera comprising an image sensor array including plurality of photosites. The method includes the operations of obtaining luminance values from the each photosite; obtaining a set of weight values for compensating the vignetting effect for the each photosite being associated with a present setting of the lightfield camera; and changing the luminance values of the each photosite based on the obtained a set of the weight values.

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: A method of calibrating an image acquisition device is described. The method includes emitting at least one light source pattern in an object space of the image acquisition device, adjusting one of the source patterns until an image pattern of the source pattern formed on a sensor of the image acquisition device exhibit a shape which centroid corresponds to a centroid of a reference pixel of the sensor, called a target image pattern and analyzing the adjusted source pattern and estimating therefrom at least one characteristic of a pixel beam directed to the reference pixel from the adjusted source pattern.

Abstract: A method for displaying at least one light field based image on a user's device is disclosed. Such a method comprises displaying the image focused according to at least one focusing parameter determined as a function of a pose of the user's device. A sensor embedded in the users' device, which may be a handheld device, may estimate the pose.

Abstract: A method for controlling a path of a rotary-wing drone wherein said method comprises: Establishing a first-order temporal relation between flight control parameters and flight dynamics for said rotary-wing drone comprising: An Explicit Discrete Time-Variant State-Space Representation of a translation control of said rotary-wing drone; An Explicit Discrete Time-Variant State-Space Representation of a course control of said rotary-wing drone; Controlling the path of said rotary-wing drone by: Estimating a course of said rotary-wing drone on the basis of said Explicit Discrete Time-Variant State-Space Representation of a course control of said rotary-wing drone; Estimating a position of said rotary-wing drone on the basis of said Explicit Discrete Time-Variant State-Space Representation of a translation control of said rotary-wing drone; said steps of estimating being performed independently.

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: A method for adapting 3D video content to a display under different viewing conditions is disclosed. The method has the steps of: retrieving a stereoscopic image pair; obtaining a maximum disparity value for the stereoscopic image pair; determining a largest allowable shift for the stereoscopic image pair using the obtained maximum disparity value; calculating an actual shift for a left image and a right image of the stereoscopic image pair using the determined largest allowable shift; and shifting the left image and the right image in accordance with the calculated actual shift.

Abstract: The invention relates to three dimensional video imaging, in which at least a left view and a right view of a moving scene are produced and a map of disparities is produced for all pixels of the successive images of a video sequence.

Abstract: An electronic imaging device having a plurality of photosensitive cells arranged in an array to form a frame region, the frame region being composed of a plurality of frame sub-regions each frame sub-region corresponding to a sub-set of photosensitive cells, the device comprising an array controller configured to expose each of said frame sub-regions during an exposure duration wherein the exposure of at least some of said frame sub-regions occurs at different times during a total time of exposure of the frame region, a flash unit for illuminating a scene to be imaged during a flash time duration an activator for activating the flash unit to illuminate the scene to be imaged at a flash time delay determined in dependence upon said exposure duration of a frame sub region and the flash time duration; an image data acquisition unit for acquiring a set of frames of the scene wherein the time of occurrence of a flash event within a frame shifts temporally from frame to frame; and an image reconstruction unit for c

Abstract: A method of filtering a disparity mesh from pixel images according to the invention, where the disparity mesh comprises a plurality of points, where each point is associated with values of two planar coordinates (X, Y) and a disparity value (D) and where the values are quantization pitches, comprises the step: filtering planes by filtering 2D-lines in 2D-spaces (X-D, Y-D) of the planar coordinates (X,Y) and the disparity (D).

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 invention relates to three dimensional video imaging, in which at least a left view and a right view of a moving scene are produced and a map of disparities is produced for all pixels of the successive images of a video sequence.

Abstract: A method of filtering a disparity mesh from pixel images according to the invention, where the disparity mesh comprises a plurality of points, where each point is associated with values of two planar coordinates (X, Y) and a disparity value (D) and where the values are quantization pitches, comprises the step: filtering planes by filtering 2D-lines in 2D-spaces (X-D, Y-D) of the planar coordinates (X,Y) and the disparity (D).

Abstract: A method for coding a 3D video signal is described. The coding method comprises a step of coding current, depth and occlusion images. According to the invention, the current occlusion image is coded according to the following steps for: coding for each block of the current occlusion image a binary identifier indicating if said block is coded or not, and coding occlusion data for each block for which the binary identifier indicates that the block is coded.