Fondation B Com

B-com

Antonin Gilles

Patrick Gioia

Remi Cozot

Luce Morin

Disclosed is a method for constructing a digital hologram to be displayed by of a display system. The display system includes a light modulator producing a light beam and a convergent optical device designed to make the light beam converge towards a focal point. The scene is defined by a set of luminous elements. The construction method includes a step of determining values respectively associated with the pixels of the digital hologram by summing the light contributions respectively produced by the luminous elements with weighting, for each of the light contributions, by a correction coefficient depending on the area of the intersection of a surface between the convergent optical device and the focal point, and a pencil of light having a predetermined angular opening and transmitted through the convergent optical device from the luminous element producing the light contribution concerned. An associated holographic system is also described.

Method for constructing a digital hologram and associated digital holography system

Disclosed is a method and a device for coding a sequence including first and second digital holograms representing respective scenes, the digital holograms being represented by a set of wavelets each defined by a multiplet of coordinates in multidimensional space. The first and second holograms are represented by first and second coefficients respectively associated with wavelets. The coding method includes the following steps: for each second coefficient, determining a remainder by a difference between the second coefficient concerned, associated with a first wavelet defined by a given multiplet, and the first coefficient) associated with a second wavelet defined by a multiplet having as its image the multiplet by a transform in the multidimenisonal space; coding the determined remainders. The transform is determined by analysis of variation between the first scene represented by the first digital hologram and the second scene represented by the second digital hologram.

Method and device for coding a digital hologram sequence

Disclosed is a method for processing an input hologram HE associated with an input plane, to obtain an output hologram displayable on a holographic screen placed in a plane called the output plane of a display system, viewable from a viewing plane of the system. The method includes: receiving the input hologram and a position of the input plane; obtaining a first transfer matrix representative of a propagation between the input plane and the viewing plane; obtaining a second transfer matrix representative of a propagation between the viewing plane and the output plane; calculating an overall matrix of transfer of a light field emitted by the input hologram, between the input plane and the output plane, by taking the product of the two matrices; and converting the input hologram into the output hologram by applying an operator dependent of the input hologram and on the screen.

Method for processing a hologram, and associated device, holographic display system and computer program

Disclosed is a method for generating a digital hologram representing a 3D scene including an object, an object being defined by points and their associated intensity. For each object, a prior step of calculating an 'omnidirectional' angular spectrum of the light field emitted by an object in the scene on the surface of a geometric solid centered on the object, a surface of the solid being sampled according to a predetermined grid, a sample of the grid being associated with a vector frequency; for the scene, the following steps: &#x2014;obtaining a pose of an observer in the world frame of reference; &#x2014;deriving the hologram from the scene as a function of the pose obtained from the 'multidirectional' angular spectra calculated for each object. The step of calculating an angular spectrum of the light field for each object of the scene takes into account predetermined viewing directions.

Method for generating a digital hologram, associated device, holographic display system and computer program

Disclosed is a method for digitally generating a hologram in a screen plane of a hologram display device, including: obtaining intensity and depth maps of the scene corresponding to user viewpoint; projecting the points of the intensity map on planes parallel to the screen plane in a reference frame of the screen, one plane associated with one depth value of between minimum and maximum values of the depth map, a point of the intensity map projected on the plane of the planes associated with the depth value of the point in the depth map; compensating for distortion by modifying the planes of the scene, a point of one plane, called image point of an object point by conjugation of the convergent lens, being replaced by the object point; from the modified planes, propagating a complex sampled light wave to the screen plane and summation of the propagated light waves.

Method for digitally generating a hologram, device, terminal device, associated system and computer program

A method for digitally generating a hologram plane from a three-dimensional scene, cut into a plurality of planes parallel to the hologram plane. The method includes for a current plane: counting a number of points of the non-zero amplitude scene; choosing a first or second technique for propagating a light wave emitted by the current plane as a function of a number of points of non-zero amplitude included in the current plane and with a preset threshold value, the first, point-based technique calculating the propagation of a sum of light waves emitted by point sources constituted by the points of the scene portion of a non-zero amplitude of the current plane on a following plane, and the second, field-based technique, globally calculating a light wave emitted by the scene portion situated in the current plane on a given plane; and processing the current plane according to the chosen propagation technique.

Growing community of inventors

Rennes, France

Antonin Gilles