Foveation and spatial hashing in layer-based computer-generated holograms

Patent metadata

Field	Value
Publication number	US-11635623-B2
Application number	US-202016937235-A
Country	US
Kind code	B2
Filing date	Jul 23, 2020
Priority date	Jul 23, 2020
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

The computational scaling challenges of holographic displays are mitigated by techniques for generating holograms that introduce foveation into a wave front recording planes approach to hologram generation. Spatial hashing is applied to organize the points or polygons of a display object into keys and values.

First claim

What is claimed is:

1. A non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a computer, cause the computer to:
generate a plurality of wave front recording planes;
apply spatial hashing to a summation of at least one field contribution propagated from points of a display object to each of the wave front recording planes; and
separately propagate a foveal component and a peripheral component of the wave front recording planes to a foveated hologram.

2. The computer-readable storage medium of claim 1 , wherein the display object is a polygonal object.

3. The computer-readable storage medium of claim 1 , wherein the display object is a point cloud.

4. The computer-readable storage medium of claim 3 , wherein the instructions further configure the computer to:
in a first pass, apply a first graphics processing unit kernel to iterate through the points in the point cloud and determining a set of key value pairs for pixels of the wave front recording planes.

5. The computer-readable storage medium of claim 4 , wherein the array is hashed into a hash table.

6. The computer-readable storage medium of claim 4 , wherein the instructions further configure the computer to:
in a second pass, apply a second graphics processing unit kernel to iterate through the pixels to generate contributions from the field.

7. A computing apparatus, the computing apparatus comprising:
a processor; and
a memory storing instructions that, when executed by the processor, configure the apparatus to:
apply a wave front recording plane to one or more objects in a scene to be rendered on a holographic display; and
apply spatial hashing to transform the objects into key value pairs where a key defines an individual position on the wave front recording plane and a value represents a point or polygon of the objects that contributes to a field at the individual key position in the wave front recording plane.

8. The computing apparatus of claim 7 wherein the instructions further configure the apparatus to:
foveate the wave front recording plane.

9. The computing apparatus of claim 8 , wherein the instructions further configure the apparatus to:
determine a foveal component and a peripheral component of the wave front recording plane;
transform the foveal component and the peripheral component into a frequency domain to generate a transformed foveal component and a transformed peripheral component;
combine the transformed foveal component and the transformed peripheral component to generate a combined transformation; and
adjust phases of the combined transformation.

10. The computing apparatus of claim 8 , wherein the instructions further configure the apparatus to:
generate a foveal component and a peripheral component of the wave front recording plane;
transform the foveal component and the peripheral component into a frequency domain to generate a transformed foveal component and a transformed peripheral component;
adjust phases of the transformed foveal component and the transformed peripheral component; and
combine the transformed foveal component and the transformed peripheral component in the frequency domain.

11. The computing apparatus of claim 8 , wherein the instructions further configure the apparatus to:
sample a foveal component and a peripheral component of the wave front recording plane;
propagate the foveal component and the peripheral component separately to a first component hologram and a second component hologram; and
combine the component holograms into a foveated hologram.

12. The computing apparatus of claim 8 , wherein the instructions further configure the apparatus to:
generate a foveal component and a peripheral component of the wave front recording plane;
combine the foveal component and the peripheral component at a position of the wave front recording plane to generate a foveated wave front recording plane; and
propagate the foveated wave front recording plane to a position of a hologram.

13. A method comprising:
applying a wave front recording plane to calculate an electric field proximate to an object representation in a scene to be rendered on a holographic display; and
applying spatial hashing to structure the object representation into key value pairs where a key defines an individual key position on the wave front recording plane and a value represents a point or polygon of the object representation that contributes to light at the individual key position in the wave front recording plane.

14. The method of claim 13 further comprising:
applying foveation to the wave front recording plane.

15. The method of claim 14 , further comprising:
sampling a foveal component and a peripheral component of the wave front recording plane separately;
transforming the foveal component and the peripheral component into a frequency domain to generate a transformed foveal component and a transformed peripheral component;
combining the transformed foveal component and the transformed peripheral component in the frequency domain to generate a combined transformation; and
adjusting phases of the combined transformation using angular spectrum techniques.

16. The method of claim 14 , further comprising:
sampling a foveal component and a peripheral component of the wave front recording plane separately;
transforming the foveal component and the peripheral component into a frequency domain to generate a transformed foveal component and a transformed peripheral component;
adjusting phases of the transformed foveal component and the transformed peripheral component using angular spectrum techniques; and
combining the transformed foveal component and the transformed peripheral component in the frequency domain to generate a combined transformation.

17. The method of claim 14 , further comprising:
sampling a foveal component and a peripheral component of the wave front recording plane separately;
propagating the foveal component and the peripheral component separately to a first component hologram and a second component hologram; and
combining the component holograms into a foveated hologram.

18. The method of claim 14 , further comprising:
sampling a foveal component and a peripheral component of the wave front recording plane separately;
combining the foveal component and the peripheral component at a position of the wave front recording plane to generate a foveated wave front recording plane; and
propagating the foveated wave front recording plane to a position of a hologram.

19. A method comprising:
generating a plurality of wave front recording planes; and
applying spatial hashing to a summation of at least one field from points or polygons of a display object to each of the wave front recording planes.

20. The method of claim 19 , further comprising:
in a first pass, applying a first graphics processing unit kernel to iterate through the points or polygons and determining a set of pixels of the wave front recording planes that correspond to each of the points or polygons to generate an array of key value pairs.

21. The method of claim 20 , wherein the array is hashed into a Cuckoo hash table.

22. The method of claim 20 , further comprising:
in a second pass, applying a second graphics processing unit kernel to iterate through the set of pixels to identify a set of contribution points from the field.

23. A method comprising:
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Assignees

• Nvidia Corp

Inventors

• Wang Jui-Hsien
• Lopes Ward
• Brown Rachel Anastasia
• Shirley Peter

Classifications

• G06F16/9014

  hash tables · CPC title

• G06T15/005

  General purpose rendering architectures · CPC title

• G02B2027/0174

  holographic · CPC title

• H04L9/0643

  Hash functions, e.g. MD5, SHA, HMAC or f9 MAC · CPC title

• G02B27/0093

  with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking · CPC title