Hybrid method for 3D shape measurement

• US 20110080471A1
• Filed: 10/05/2010
• Published: 04/07/2011
• Est. Priority Date: 10/06/2009
• Status: Abandoned Application

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Song, Zhang, Oliver, James H.
• Application Number:
  US12/924,765
• Publication Number:
  US 20110080471A1
• Time in Patent Office: Days
• US Class Current: 348/46
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G01B 11/2527 with phase change by in-plane movement of the patern
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/30048 Heart; Cardiac
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A method for three-dimensional shape measurement provides for generating sinusoidal fringe patterns by defocusing binary patterns. A method for three-dimensional shape measurement may include (a) projecting a plurality of binary patterns onto at least one object; (b) projecting three phase-shifted fringe patterns onto the at least one object; (c) capturing images of the at least one object with the binary patterns and the phase-shifted fringe patterns; (d) obtaining codewords from the binary patterns; (e) calculating a wrapped phase map from the phase-shifted fringe patterns; (f) applying the codewords to the wrapped phase map to produce an unwrapped phase map; and (g) computing coordinates using the unwrapped phase map for use in the three-dimensional shape measurement of the at least one object. A system for performing the method is also provided. The high-speed real-time 3D shape measurement may be used in numerous applications including medical science, biometrics, and entertainment.

Claims

1. A method for three-dimensional shape measurement, comprising:

generating sinusoidal fringe patterns by projecting defocused binary patterns onto an object to thereby produce phase-shifted fringe patterns;

capturing images of the object with the phase-shifted fringe patterns produced thereon; and

evaluating the images for use in the three-dimensional shape measurement.

2. The method of claim 1 wherein the projecting being performed using a digital micro mirror device (DMD) based projection system.

3. The method of claim 2 wherein the digital micro mirror device (DMD) based projection system comprises a digital light processing (DLP) projector.

4. The method of claim 1 wherein the object is in motion.

5. The method of claim 1 wherein the method being performed in real-time.

6. The method of claim 1 wherein the evaluating comprises

(a) obtaining codewords from the binary patterns;

(b) calculating a wrapped phase map from the phase-shifted fringe patterns;

(c) applying the codewords to the wrapped phase map to produce an unwrapped phase map; and

(d) computing coordinates using the unwrapped phase map for use in the three-dimensional shape measurement of the at least one object.

7. A method for three-dimensional shape measurement, comprising:

(a) projecting a plurality of binary patterns onto at least one object;

(b) projecting three phase-shifted fringe patterns onto the at least one object;

(c) capturing images of the at least one object with the binary patterns and the phase-shifted fringe patterns;

(d) obtaining codewords from the binary patterns;

(e) calculating a wrapped phase map from the phase-shifted fringe patterns;

(f) applying the codewords to the wrapped phase map to produce an unwrapped phase map; and

(g) computing coordinates using the unwrapped phase map for use in the three-dimensional shape measurement of the at least one object.

8. The method of claim 7 wherein the at least one object is a plurality of objects.

9. The method of claim 7 further comprising constructing a view of the at least one object using the coordinates.

10. The method of claim 9 wherein the steps (a)-(g) are repeated using multiple projectors and multiple cameras and wherein the view is a panoramic view.

11. The method of claim 7 wherein the at least one object comprises biological tissue in motion.

12. The method of claim 11 wherein the biological tissue includes a heart.

13. The method of claim 7 wherein the steps of (a)-(g) are performed in real-time.

14. The method of claim 7 wherein the steps are performed by a system comprising at least one projector, at least one camera, and at least one system processor operatively connected to the at least one projector and the at least one camera.

15. The method of claim 7 further comprising correcting incorrectly unwrapped points by computing a gradient of the wrapped phase map.

16. A system for three-dimensional shape measurement, comprising:

at least one projector;

at least one camera;

at least one system processor;

wherein the system being configured to perform steps of (a) generating sinusoidal fringe patterns by projecting defocused binary patterns onto an object to thereby produce phase-shifted fringe patterns, (b) capturing images of the object with the phase-shifted fringe patterns produced thereon, and (c) evaluating the images for use in the three-dimensional shape measurement.

17. The system of claim 16 wherein the at least one object is a plurality of objects.

18. The system of claim 16 wherein the system being further configured for constructing a view of the at least one object using the coordinates.

19. The system of claim 16 wherein the at least one projector comprises a plurality of projectors and the at least one camera comprises a plurality of cameras, the plurality of projectors and the plurality of cameras being arranged to provide for obtaining a panoramic view of the at least one object.

20. The system of claim 16 wherein the at least one object comprises biological tissue in motion.

21. The system of claim 16 wherein the biological tissue includes a heart.

22. The system of claim 16 wherein the system processor being further configured for correcting incorrectly unwrapped points by computing a gradient of the wrapped phase map.

23. A system for three-dimensional shape measurement, comprising:

at least one projector;

at least one camera;

at least one system processor;

wherein the system being configured to perform steps of (a) projecting a plurality of binary patterns onto at least one object, (b) projecting three phase-shifted fringe patterns onto the at least one object, (c) capturing images of the at least one object with the binary patterns and the phase-shifted fringe patterns, (d) obtaining codewords from the binary patterns, (e) calculating a wrapped phase map from the phase-shifted fringe patterns, (f) applying the codewords to the wrapped phase map to produce an unwrapped phase map, and (g) computing coordinates using the unwrapped phase map for use in the three-dimensional shape measurement of the at least one object.

24. A method for three-dimensional shape measurement, comprising generating sinusoidal fringe patterns by defocusing binary patterns.

25. The method of claim 24 further comprising projecting the sinusoidal fringe patterns onto at least one object.

26. The method of claim 25 further comprising capturing images of the at least one object with the sinusoidal fringe patterns.

27. The method of claim 26 further comprising evaluating the images for use in the three-dimensional shape measurement.

28. The method of claim 25 wherein the projecting being performed using a digital micro mirror device (DMD) based projection system.

29. The method of claim 25 wherein the digital micro mirror device (DMD) based projection system comprises a digital light processing (DLP) projector.

30. The method of claim 25 wherein the at least on object being in motion.

31. The method of claim 27 wherein the evaluating being performed using a graphics processing unit (GPU).

32. A system for three-dimensional shape measurement, comprising:

at least one projector;

at least one camera;

at least one system processor; and

wherein the system being configured to generate sinusoidal fringe patterns by defocusing binary patterns, projecting the sinusoidal fringe patterns onto at least one object, capturing images of the at least one object with the sinusoidal fringe patterns, and evaluating the images to provide for three-dimensional shape measurement of the at least one object.

33. The system of claim 32 wherein the at least one projector includes a digital micro mirror device (DMD) based projection system.

34. The system of claim 33 wherein the digital micro mirror device (DMD) based projection system includes a digital light processing (DLP) projector.

35. The system of claim 32 wherein the system processor includes at least one graphics processing unit (GPU).