Three dimensional information measurement method and apparatus

• US 6,204,916 B1
• Filed: 02/03/1999
• Issued: 03/20/2001
• Est. Priority Date: 02/03/1998
• Status: Expired due to Term

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Yagi, Fumiya, Norita, Toshio
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US09/243,809
• Time in Patent Office: 776 Days
• Field of Search: 356/4.01, 356/141--14, 356/139-1-1, 702/150-153, 250/206.2
• US Class Current: 356/141.1
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

A three dimensional information measurement apparatus employing a rotator or surface-of-rotation type mirror, an imaging apparatus disposed with its light receiving axis aligned with a center axis of said rotator type mirror for measuring three dimensional information on a target placed in a space surrounding said center axis, and a reference light projection means for projecting reference light. Also, main scanning is performing by deflecting the reference light in a circumferential direction centered about the center axis or, in an alternative embodiment, avoided by providing a conically shaped reference beam. Sub scanning is performed by deflecting said reference light in a direction of projection whereby said reference light changes in a direction parallel to said center axis either by changing the angle of the main scanning mirror; and three dimensional information computing means for obtaining the three dimensional information of said target, based on a physical quantity corresponding to a projection angle representing the direction of projection of said reference light in the sub scan, and on a physical quantity corresponding to the position of a projected image obtained by said imaging apparatus and representing said reference light reflected from said target via said rotator type mirror.

Claims

1. A three dimensional information measurement method for measuring three dimensional information of a target placed in a space surrounding a center axis of a non-rotating rotator type mirror by using said rotator type mirror in combination with an imaging apparatus disposed with its light receiving axis aligned with the center axis of said rotator type mirror, comprising:

scanning said target by projecting reference light; and

obtaining the three dimensional information of said target, based on a physical quantity corresponding to a projection angle of said reference light and on a physical quantity corresponding to a position of a projected image obtained when said reference light reflected from said target is captured by said imaging apparatus via said rotator type mirror.

2. A three dimensional information measurement method according to claim 1, wherein said rotator type mirror has a convex reflection surface.

3. A three dimensional information measurement apparatus, comprising:

a non-rotating rotator type mirror;

an imaging apparatus disposed with its light receiving axis aligned with a center axis of said rotator type mirror, for measuring three dimensional information of a target placed in a space surrounding said center axis;

a reference light projector for projecting reference light in the form of a beam;

a first scanner for performing a main scan by deflecting said reference light in a direction of projection whereby said direction of projection changes in a circumferential direction centered about said center axis;

a second scanner for performing a sub scan by deflecting said reference light whereby said direction of projection changes in a direction parallel to said center axis; and

a three dimensional information computing unit for obtaining the three dimensional information of said target, based on a physical quantity corresponding to a projection angle representing the direction of projection of said reference light in the sub scan, and on a physical quantity corresponding to a position of a projected image obtained by said imaging apparatus and representing said reference light reflected from said target via said rotator type mirror.

4. A three dimensional information measurement apparatus according to claim 3, wherein said rotator type mirror has a quadric surface-of-revolution.

5. A three dimensional information measurement apparatus according to claim 4, wherein said quadric surface-of-revolution is selected from a group of quadratic surfaces comprising a hyperboloid, an ellipsoid, and a paraboloid.

6. A three dimensional information measurement apparatus according to claim 3, wherein said imaging apparatus includes a video camera.

7. A three dimensional information measurement apparatus according to claim 3, wherein said reference light projector includes a light beam source and an optical system forming a beam spot.

8. A three dimensional information measurement apparatus according to claim 3, wherein said first scanner includes a scanning mirror and a rotational driving device.

9. A three dimensional information measurement apparatus according to claim 8, wherein said second scanner includes an angular controller for controlling an angle of said scanning mirror about an axis perpendicular to said center axis.

10. A three dimensional information measurement apparatus according to claim 8, wherein said second scanner includes a scanning lens and a driver for moving said scanning lens parallel to said center axis.

11. A three dimensional information measurement apparatus according to claim 10, wherein said scanning lens rotates about said center axis in accordance with said scanning mirror.

12. A three dimensional information measurement apparatus according to claim 10, wherein said scanning lens has an annular shape symmetric about said center axis.

13. A three dimensional information measurement apparatus according to claim 3, wherein said rotator type mirror has a convex reflection surface.

14. A three dimensional information measurement apparatus according to claim 3, wherein said imaging apparatus is kept stationary at a fixed position during said main scan.

15. A three dimensional information measurement apparatus according to claim 3, wherein said rotator type mirror has a reflecting surface with the shape of a line or curve rotated about said center axis.

16. A three dimensional information measurement apparatus, comprising

a non-rotating rotator type mirror;

an imaging apparatus disposed with its light receiving axis aligned with a center axis of said rotator type mirror, for measuring three dimensional information of a target placed in a space surrounding said center axis;

a radiating reference light projector for projecting radiating reference light into a surrounding area;

a scanner for performing a scan by deflecting said reference light in such a manner as to change a projection angle of said reference light; and

a three dimensional information computing unit for obtaining the three dimensional information of said target, based on a physical quantity corresponding to said projection angle representing a direction of projection of said reference light in the scan, and on a physical quantity corresponding to a position of a projected image obtained by said imaging apparatus and representing said reference light reflected from said target.

17. A three dimensional information measurement apparatus according to claim 16, wherein said radiating reference light projector includes a light projection apparatus for forming an annular shaped reference light when viewed in a plane perpendicular to said center axis wherein said annular shaped reference light increases in diameter as its optical distance to said light projection apparatus increases.

18. A three dimensional information measurement apparatus according to claim 16, wherein said scanner includes a cylindrically shaped mask and a driver for changing the orientation of said cylindrically shaped mask with respect to said center axis.

19. A three dimensional information measurement apparatus according to claim 16, wherein said scanner includes a cylindrically shaped mask with an annular slit there around and a driver for moving said cylindrically shaped mask along said center axis.

20. A three dimensional information measurement apparatus according to claim 16, wherein said scanner includes a cylindrically shaped mask with a helical slit there around and a driver for rotating said cylindrically shaped mask about said center axis.

21. A three dimensional information measurement apparatus according to claim 16, wherein said rotator type mirror has a convex reflection surface.

22. A three dimensional information measurement apparatus, comprising

a non-rotating rotator type mirror;

an imaging apparatus disposed with its light receiving axis aligned with a center axis of said rotator type mirror, for measuring three dimensional information of a target placed in a space surrounding said center axis;

a radiating reference light projector for projecting radiating reference light into a surrounding area;

a scanner for performing a scan by deflecting said reference light in such a manner as to change a projection angle of said reference light, wherein said scanner includes another rotator type mirror and a driver for moving said other rotator type mirror along said center axis; and

a three dimensional information computing unit for obtaining the three dimensional information of said target, based on a physical quantity corresponding to said projection angle representing a direction of projection of said reference light in the scan, and on a physical quantity corresponding to a position of a projected image obtained by said imaging apparatus and representing said reference light reflected from said target.

23. A three dimensional information measurement apparatus according to claim 22, wherein said rotator type mirror has a convex reflection surface.

24. A three dimensional information measurement apparatus, comprising:

a non-rotating rotator type mirror;

an imaging apparatus disposed with its light receiving axis aligned with a center axis of said rotator type mirror, for measuring three dimensional information of a target placed in a space surrounding said center axis;

a reference light projector for projecting reference light in the form of a beam;

a scanner for deflecting said reference light in a direction of projection whereby said direction of projection changes in a circumferential direction centered about said center axis and for deflecting said reference light whereby said direction of projection changes in a direction parallel to said center axis; and

a three dimensional information computing unit for obtaining the three dimensional information of said target, based on a physical quantity corresponding to a projection angle representing the direction of projection of said reference light in a scan, and on a physical quantity corresponding to a position of a projected image obtained by said imaging apparatus and representing said reference light reflected from said target via said rotator type mirror.

25. A three dimensional information measurement apparatus according to claim 24, wherein said scanner comprises a galvanometer scanner.

26. A three dimensional information measurement apparatus according to claim 24, wherein said scanner includes another rotator type mirror and a driver for moving said other rotator type mirror along said center axis.

27. A three dimensional information measurement apparatus according to claim 24, wherein said rotator type mirror has a convex reflection surface.