Method and holographic apparatus for the three-dimensional representation of scenes

Patent metadata

Field	Value
Publication number	US-12204282-B2
Application number	US-202017598253-A
Country	US
Kind code	B2
Filing date	Mar 23, 2020
Priority date	Mar 25, 2019
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

An apparatus and method for the three-dimensional representation of scenes including an illumination device and a spatial light modulation device for modulating incident light. A hologram is encoded into the spatial light modulation device and the hologram is composed of individual sub-holograms, in which an object point of an object of the scene to be reconstructed by the hologram is encoded in each case. The spatial light modulation device is illuminated with substantially coherent light by the illumination device in at least one illumination section. An amplitude distribution and a phase distribution for representing the scene and amplitude values and phase values derived therefrom are determined for encoding the spatial light modulation device. The amplitude of the light incident on the spatial light modulation device in the respective illumination section is set based on at least one parameter at least determined from the amplitude values in this illumination section.

First claim

The invention claimed is:

1. A method for a three-dimensional representation of scenes comprising an illumination device and at least one spatial light modulation device for modulating incident light, where a hologram is encoded into the at least one spatial light modulation device and the hologram is composed of individual sub-holograms, in which an object point of an object of a scene to be reconstructed by the hologram is encoded in each case, where the at least one spatial light modulation device is illuminated with substantially coherent light by the illumination device in at least two illumination sections, where an amplitude distribution and a phase distribution for representing the scene and amplitude values and phase values derived therefrom are determined for encoding the at least one spatial light modulation device, and where an amplitude of the light incident on the at least one spatial light modulation device in the respective illumination section is set, by a component other than the at least one spatial light modulation device, on a basis of at least one parameter at least determined from the amplitude values in this illumination section.

2. The method as claimed in claim 1 , wherein a virtual observer window in an observer plane is provided, a noise window being assigned to said observer window, where the at least one spatial light modulation device comprises a phase modulating light modulator, where control signals for controlling the at least one spatial light modulation device are determined in an iterative method, where the amplitude of the light incident on the at least one spatial light modulation device in the respective illumination section is set on the basis of at least the parameter.

3. The method as claimed in claim 2 , wherein complex values of a light wavefield are assigned to the virtual observer window and the noise window, where a complex target value distribution of the light wavefield in the virtual observer window is determined from the scene, where the complex values in the observer plane are transformed into a hologram plane by means of an inverse transformation in an iteration step, where absolute values of the complex values in the hologram plane are set to a target absolute value for each illumination section, where the complex values obtained thus are transformed into the observer plane by means of a transformation and replaced by the complex target value distribution in the virtual observer window, where a parameter is determined in the hologram plane from the target absolute value in the respective illumination section present after a termination criterion of the iteration has been attained or from absolute values of the complex values in the respective illumination section after reaching a termination criterion of the iteration.

4. The method as claimed in claim 3 , wherein the parameter is defined before a start of iteration and in that the target absolute value in the respective illumination section is equated to the parameter and remains the same for all iteration steps or in that the parameter is set after the termination criterion of the iteration has been reached and the target absolute value is adapted in each iteration step.

5. The method as claimed in claim 2 , wherein the parameter is determined from average values of the absolute values of the complex values in the respective illumination section in the hologram plane present after a termination criterion of iteration has been reached.

6. The method as claimed in claim 2 , wherein the target absolute value in the respective illumination section is determined before the start of the iteration or after a first iteration step from the absolute values of the complex values present in the hologram plane and/or in that the target absolute value in the respective illumination section is determined on a basis of the brightness of the object points to be reconstructed or on the basis of parameters of sub-holograms, or on the basis of parameters of sub-holograms being a position of object points to be represented relative to a relative position of the at least one spatial light modulation device or the density of object points.

7. The method as claimed in claim 1 , wherein the at least one spatial light modulation device comprises an amplitude modulating light modulator, where control signals for controlling the at least one spatial light modulation device are determined, where the control signals serve to set amplitude values on a basis of at least the parameter and the amplitude values.

8. The method as claimed in claim 1 , wherein the parameter is determined from a ratio of a maximum amplitude value in the respective illumination section to a maximum possible amplitude value on the at least one spatial light modulation device.

9. The method as claimed in claim 1 , wherein the parameter is determined at least one of: on a basis of a brightness of the object points to be reconstructed, on a basis of parameters of the sub-holograms, or on a basis of parameters of the sub-holograms being a position of object points to be represented relative to a relative position of the at least one spatial light modulation device, and a density of object points.

10. The method as claimed in claim 1 , wherein the illumination device comprises at least one light source, where an illumination section is illuminated by the at least one light source and where the at least one light source assigned to an illumination section is set in terms of its amplitude in accordance with the parameter determined for the illumination section, or in that the illumination device comprises at least one light source, where at least one secondary light source is generated by the light of the at least one light source, where an illumination section is illuminated by the at least one secondary light source and where the at least one secondary light source assigned to an illumination section is set in terms of its amplitude in accordance with the parameter determined for the illumination section.

11. The method as claimed in claim 1 , wherein the illumination device comprises at least one light source, where the light of the at least one light source is fed via at least one switchable optical element to the at least one spatial light modulation device and where an amplitude of the light fed to an illumination section is set using the at least one switchable optical element on a basis of the parameter determined for the illumination section.

12. The method as claimed in claim 1 , wherein the amplitude of the light fed to an illumination section is set continuously or discontinuously on a basis of the parameter determined for the illumination section or in that an amplitude averaged over a time interval is set on a basis of the parameter by pulse width modulation.

13. The method as claimed in claim 1 , wherein the at least one spatial light modulation device is illuminated by at least two light sources with respectively assigned imaging elements, where each light source illuminates an illumination section of the at least one spatial light modulation device and where the amplitude of the light of the light source assigned to the respective illumination section is set in accordance with the parameter.

14. The method as claimed in claim 1 , wherein the at least one spatial light modulation device is illuminated by at least one light source, where a shutter arrangement with portions that are continuously or discontinuously adjustable in terms of their transparency is arranged between the at least one light source and the at least one spatial light modulation device, where imaging elements are assigned to adjustable port

Assignees

• Seereal Technolgies S A
• Seereal Tech S A

Inventors

• Leister Norbert
• Lazarev Grigory

Classifications

• G03H2222/34

  Multiple light sources · CPC title

• G03H2210/30

  3D object · CPC title

• G03H2001/2236

  Details of the viewing window · CPC title

• G03H1/0841

  Encoding method mapping the synthesized field into a restricted set of values representative of the modulator parameters, e.g. detour phase coding · CPC title

• G02F1/133601

  for spatial active dimming · CPC title