A method for producing a hologram (1), (1) for security elements (1a) and/or security documents (1b). One or more virtual hologram planes (10) are arranged in front of and/or behind one or more virtual models (20) and/or one or more virtual hologram planes (10) are arranged such that they intersect one or more virtual models (20). One or more virtual light sources (30) are arranged on one or more partial regions of the surface (21) of one or more of the virtual models (20). One or more virtual electromagnetic fields (40) are calculated starting from at least one of the virtual light sources (30) in one or more zones (11) of the one or more virtual hologram planes (10). In the one or more zones (11), in each case, a virtual total electromagnetic field (41) is calculated on the basis of the sum of two or more, of the virtual electromagnetic fields (40) in the respective zone (11). One or more phase images (50) are calculated from the virtual total electromagnetic fields (41) in the one or more zones (11). A height profile (60) of the hologram (1) is calculated from the one or more phase images (50) and the height profile (60) of the hologram (1) is incorporated into a substrate (2) to provide the hologram (1).

Methods, apparatus, devices, and systems for three-dimensional (3D) displaying objects are provided. In one aspect, a method includes obtaining data including respective primitive data for primitives corresponding to an object, determining an electromagnetic (EM) field contribution to each element of a display for each of the primitives by calculating an EM field propagation from the primitive to the element, generating a sum of the EM field contributions from the primitives for each of the elements, transmitting to each of the elements a respective control signal for modulating at least one property of the element based on the sum of the EM field contributions, and transmitting a timing control signal to an illuminator to activate the illuminator to illuminate light on the display, such that the light is caused by the modulated elements of the display to form a volumetric light field corresponding to the object.

The invention relates to a method for generating holograms for encoding in a spatial light modulation device for a holographic display for representing a two- and/or three-dimensional scene. The two- and/or three-dimensional scene is decomposed into object points and encoded in a hologram, which is subdivided into subholograms, in the spatial light modulation device. The object points of the scene are encoded into encoding regions on the spatial light modulation device. A size and/or shape of the encoding region is selected in relation to a size and/or shape of a subhologram, assigned to the encoding region, in such a way that crosstalk of higher diffraction orders in a virtual visibility region is reduced.

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: —obtaining a pose of an observer in the world frame of reference; —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.

The present disclosure relates to a method for computing a holographic interference pattern for a holographic plane including pixels of an illuminated three-dimensional, 3D, scene having object points representing one or more 3D objects. The method involves: determining, for a respective object point, a total light component contributed by one or more light sources in the 3D scene; and calculating, for a respective pixel, a complex-valued amplitude based on the total light component of non-occluded object points within a viewing cone of the pixel, thereby deriving the holographic interference pattern. The present disclosure further relates to a computer program product implementing the method, a computer-readable storage medium comprising the computer program product and a data processing system for carrying out the method.

Disclosed is a method of generating a volume hologram using a point cloud and a mesh, in which a weight is given to a brightness of a light source according to a direction of a light in order to record a hologram of better quality. The method includes: (a) acquiring multi-view depth and color images; (b) generating point cloud data of a three-dimensional object from the acquired multi-view depth and color images; (c) generating mesh data of the three-dimensional object from the point cloud data of the three-dimensional object; (d) calculating a normal vector of each mesh from the mesh data of the three-dimensional object; (e) extracting three-dimensional data at a user viewpoint from the mesh data of the three-dimensional object by using the normal vector of the mesh; and (f) generating hologram data from three-dimensional data at the user viewpoint.

An apparatus and a method for optimized calculation of 2D sub-holograms for object points of a three-dimensional scene and a pipeline for real-time calculation of holograms are provided. The invention shortens the calculation time of a hologram for representing a three-dimensional scene and/or to reduce the calculation complexity of such a hologram. This is achieved by a 2D sub-hologram of an object point, which has image elements of the spatial light modulator, comprises a half 1D sub-hologram, where the radius of each image element is determined and each image element of the 2D sub-hologram is fixedly assigned to at least one image element of the half 1D sub-hologram with identical or similar radius by way of an electronic circuit, by a method for encoding a hologram, and by a pipeline on the basis of FPGA and/or ASIC.

A method for generating video holograms in real time for a holographic playback device comprising at least one light modulator means, into which a scene divided into object points is encoded as an entire hologram and can be seen as a reconstruction from a visibility region, which is located within a periodicity interval of the reconstruction of the video hologram, the visibility region defining a subhologram together with each object point of the scene to be reconstructed, and the entire hologram being generated from a superposition of contributions of subholograms, is characterized in that for each object point the contributions of the subholograms in the entire reconstruction of the scene can be determined from at least one look-up table.

The invention relates to methods for computing holograms for holographic reconstruction of two-dimensional and/or three-dimensional scenes in a display apparatus, wherein a scene for reconstruction is broken down into object points and the object points are encoded as sub-holograms into at least one spatial light modulation device of the display apparatus. A reconstructed scene is viewed from a region of visibility. At least one virtual plane of the at least one spatial light modulation device is stipulated on the basis of a real plane of the spatial light modulation device. A computation of sub-holograms is performed in the at least one virtual plane of the at least one spatial light modulation device.

Methods, apparatus, devices, and systems for three-dimensional (3D) displaying objects are provided. In one aspect, a method includes obtaining data including respective primitive data for primitives corresponding to an object, determining an electromagnetic (EM) field contribution to each element of a display for each of the primitives by calculating an EM field propagation from the primitive to the element, generating a sum of the EM field contributions from the primitives for each of the elements, transmitting to each of the elements a respective control signal for modulating at least one property of the element based on the sum of the EM field contributions, and transmitting a timing control signal to an illuminator to activate the illuminator to illuminate light on the display, such that the light is caused by the modulated elements of the display to form a volumetric light field corresponding to the object.