Method and system for multi-wavelength depth encoding for three dimensional range geometry compression

Patent metadata

Field	Value
Publication number	US-10602118-B2
Application number	US-201615367221-A
Country	US
Kind code	B2
Filing date	Dec 2, 2016
Priority date	Dec 2, 2015
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

A method for generating encoded depth data includes receiving digital fringe projection (DFP) data corresponding to a three-dimensional structure of a physical object, and generating first and second fringe encodings for a first predetermined wavelength based on the DFP data at a first coordinate. The method further includes generating third and fourth fringe encodings for a second predetermined wavelength based on the DFP data at the first coordinate, the second wavelength being longer than the first wavelength, and generating a combined fringe encoding based on the third fringe encoding and the fourth fringe encoding. The method further includes storing the first, second, and combined fringe encoding data in a pixel of two-dimensional image data at a pixel coordinate in the two-dimensional image data corresponding to the first coordinate.

First claim

What is claimed is:

1. A method for generating encoded depth data comprising:
receiving, with a processor, digital fringe projection (DFP) data corresponding to a three-dimensional structure of a physical object;
generating, with the processor, a first fringe encoding and a second fringe encoding for a first predetermined wavelength based on the DFP data at a first coordinate;
generating, with the processor, a third fringe encoding and a fourth fringe encoding for a second wavelength based on the DFP data at the first coordinate, the second wavelength being longer than the first wavelength;
generating, with the processor, a combined fringe encoding based on the third fringe encoding and the fourth fringe encoding; and
storing, with the processor, the first fringe encoding data, the second fringe encoding data, and the combined fringe encoding data in a pixel of two-dimensional image data at a pixel coordinate in the two-dimensional image data corresponding to the first coordinate, the two-dimensional image data being stored in a memory.

2. The method of claim 1 , the storing of the first fringe encoding data, the second fringe encoding data, and the combined fringe encoding data further comprising:
storing, with the processor, the first fringe encoding data in a first color channel of the pixel, the second fringe encoding data in a second color channel of the pixel, and the combined fringe encoding data in a third color channel of the pixel.

3. The method of claim 1 further comprising:
compressing, with the processor, the two-dimensional image data prior to storing the two-dimensional image data in the memory.

4. The method of claim 3 , the compressing further comprising:
compressing, with the processor, the two-dimensional image data using a lossy compression format.

5. The method of claim 3 further comprising:
compressing, with the processor, the two-dimensional image data using a lossless compression format.

6. The method of claim 1 , the generating of the first fringe encoding and the second fringe encoding further comprising:
generating, with the processor, the first fringe encoding based, at least in part, on a sine function value of a proportion of the second wavelength divided by the first predetermined wavelength; and
generating, with the processor, the second fringe encoding based, at least in part, on a cosine function value of the proportion of the second wavelength divided by the first predetermined wavelength.

7. The method of claim 1 , the generating of the third fringe encoding and the fourth fringe encoding further comprising:
generating, with the processor, the third fringe encoding based, at least in part, on a sine function value of a proportion of the second wavelength divided by a maximum range of wavelengths present in the DFP data; and
generating, with the processor, the fourth fringe encoding based, at least in part, on a cosine function value of the proportion of the second wavelength divided by a maximum range of wavelengths present in the DFP data.

8. The method of claim 7 , the generating of the combined fringe encoding further comprising:
generating, with the processor, the combined fringe encoding based, at least in part, on an arctangent of a proportion of the third fringe encoding divided by the fourth fringe encoding.

9. A method for decoding encoded digital fringe projection (DFP) data corresponding to a physical object comprising:
retrieving, with a processor, a first pixel of two-dimensional image data from a memory;
decoding, with the processor, dense phase data stored in the first pixel;
decoding, with the processor, wrapped phase data stored in the first pixel;
generating, with the processor, a stair image including a second pixel corresponding to the first pixel of the two-dimensional image data based on the dense phase data and the wrapped phase data; and
generating, with the processor, a depth map including a third pixel corresponding to the second pixel of the stair image, the third pixel storing data corresponding to a depth of a location of the physical object.

10. The method of claim 9 , the decoding of the dense phase data further comprising:
decoding, with the processor, the dense phase data based, at least in part, on an arctangent of a proportion of a first fringe encoding stored in a first color channel of the first pixel divided by a second fringe encoding stored in a second color channel of the first pixel.

11. The method of claim 9 , the decoding of the wrapped phase data further comprising:
retrieving, with the processor, the wrapped phase data from a third color channel of the first pixel; and
scaling, with the processor, the wrapped phase data from a first numeric scale to a second numeric scale with a range of values from [−π, π).

12. The method of claim 9 , the generating of the stair image further comprising:
generating, with the processor, the second pixel corresponding to the first pixel of the two-dimensional image data based, at least in part, on the wrapped phase data subtracted from a product of the dense phase data multiplied by a proportion of a maximum range of wavelengths present in the encoded DFP data divided by a predetermined wavelength that was used to generate the encoded dense phase data stored in the pixel, the predetermined wavelength being smaller than the maximum range of wavelengths.

13. The method of claim 12 , the generating of the depth map further comprising:
generating, with the processor, the third pixel corresponding to the second pixel based, at least in part, on a sum of the dense phase data added to the second pixel of the stair image function multiplied by the predetermined wavelength.

14. A system configured to generate encoded depth data comprising:
a memory; and
a processor operatively connected to the memory, the processor being configured to:
receive digital fringe projection (DFP) data corresponding to a three-dimensional structure of a physical object;
generate with the processor, a first fringe encoding and a second fringe encoding for a first predetermined wavelength based on the DFP data at a first coordinate;
generate a third fringe encoding and a fourth fringe encoding for a second wavelength based on the DFP data at the first coordinate, the second wavelength being longer than the first wavelength;
generate a combined fringe encoding based on the third fringe encoding and the fourth fringe encoding; and
store the first fringe encoding data, the second fringe encoding data, and the combined fringe encoding data in a pixel of two-dimensional image data at a pixel coordinate in the two-dimensional image data corresponding to the first coordinate, the two-dimensional image data being stored in the memory.

15. The system of claim 14 , the processor being further configured to:
store the first fringe encoding data in a first color channel of the pixel, the second fringe encoding data in a second color channel of the pixel, and the combined fringe encoding data in a third color channel of the pixel.

16. The system of claim 14 , the processor being further configured to:
compress the two-dimensional image data prior to storing the two-dimensional image data in the memory.

17. The system of claim 16 , the processor being further configured to:
compress the two-dimensional image data using a lossy compression format.

18. The system of claim 14 , the processor being further configured to:
generate the first fringe encoding based, at least in part, on a sine function value of a proportion of the second wav

Assignees

• Purdue Research Foundation

Inventors

• Zhang Song
• Bell Tyler

Classifications

• H04N13/254

  in combination with electromagnetic radiation sources for illuminating objects · CPC title

• H04N13/139

  Format conversion, e.g. of frame-rate or size · CPC title

• G01B11/2513

  with several lines being projected in more than one direction, e.g. grids, patterns · CPC title

• H04N13/161 Primary

  Encoding, multiplexing or demultiplexing different image signal components (for multi-view video sequence encoding H04N19/597) · CPC title

• H04N13/15

  for colour aspects of image signals · CPC title