Shape measure device

• US 5,848,188 A
• Filed: 09/07/1995
• Issued: 12/08/1998
• Est. Priority Date: 09/08/1994
• Status: Expired due to Fees

• Current Assignee: CKD Corporation, Kabushiki Kaisha Nextar
• Original Assignee: CKD Corporation, Kabushiki Kaisha Nextar
• Inventors: Sato, Yukio, Ishigure, Katsunori, Shibata, Susumu
• Primary Examiner(s): Mancuso, Joseph
• Application Number:
  US08/524,625
• Time in Patent Office: 1,188 Days
• Field of Search: 382/141, 382/142, 382/286, 382/284, 382/203, 348/92, 348/94, 348/95, 348/131, 348/132
• US Class Current: 382/203
• CPC Class Codes: G01B 11/024 by means of diode-array scanning
• CPC Class Codes: G01B 11/2518 Projection by scanning of the object

Abstract

Disclosed herein is a high-resolution shape measuring device having a scanning device capable of scanning an object to be measured at a high constant rotational speed. The shape measuring device includes a laser light source for generating flashing laser light, a pattern memory storing different flash patterns of the laser light, a polygon mirror as the scanning device, and a CCD camera for picking up an image formed on the object by the scanning of the laser light, wherein the shape of the object is computed according to image data obtained by the CCD camera. The shape measuring device further includes a motor for rotating the polygon mirror and a photodetector for generating a PD signal when the phase of rotation of the polygon mirror becomes a specific phase. The polygon mirror is rotated so as to scan the object plural times in a pickup time per frame of the CCD camera by using one of the flash patterns, and the flash pattern used is reset by the PD signal and is repeatedly used during the pickup time per frame. Further, the number of times of scanning for actually directing the laser light onto the object can be selected from the number of plural times of scanning performed in the pickup time per frame in order to adjust laser light quantity.

Claims

1. A shape measuring device having a laser light source for generating flash laser light, a scanning device for deflecting said laser light toward an object placed on a measurement plane to scan said object, and image pickup means for picking up image data formed on said object by scanning said laser light, said shape measuring device comprising:

driving means for driving said scanning device so that the scanning of said laser light by said scanning device over a measurement range is performed at least once in a pickup time per frame of said image pickup means;

a pattern memory preliminarily storing plural kinds of flash patterns of said laser light;

flash control means for controlling flashing of said laser light from said laser light source based on a phase of scanning by said scanning device and one of said flash patterns stored in said pattern memory;

generating means for generating space code data from the image data obtained by said image pickup means; and

shape computing means for computing a shape of said object from the space code data.

2. A shape measuring device according to claim 1, wherein:

said scanning device comprises a polygon mirror;

said driving means rotationally drives said polygon mirror so that the scanning of said laser light by said polygon mirror over a measurement plane is performed plural times in a pickup time per frame of said image pickup means;

said shape measuring device further comprises phase reference signal generating means for detecting a phase of rotation of said polygon mirror and generating a phase reference signal when said phase becomes a specific phase;

said flash control means controls the flashing of said laser light from said laser light source with reference to said phase reference signal according to one of said flash patterns stored in said pattern memory; and

said shape measuring device further comprises pattern changing means for changing said flash pattern followed by said flash control means when said pickup time per frame of said image pickup means has elapsed.

3. A shape measuring device according to claim 2, further comprising light quantity adjusting means for setting the number of times of scanning for actually directing said laser light onto said object in said plural times of scanning performed in said pickup time per frame of said image pickup means.

4. A shape measuring device according to claim 1, wherein:

said laser light is a slit-shaped beam;

said image formed on said object by the scanning of said laser light is a stripe pattern; and

said shape measuring device further comprises drive timing means for adjusting generation of a drive signal from said driving means so as to correct a nonlinear relation between said drive signal and an actual deflection angle of said scanning device.

5. A shape measuring device according to claim 4, wherein said drive timing means calculates a correction quantity for said drive signal from said image data obtained by said image pickup means when measurement is made on said measurement plane perpendicular to an optical axis of said image pickup means in a condition where said object is absent on said measurement plane.

6. A shape measuring device according to claim 5, further comprising:

flash timing means for controlling the flashing of said laser light from said laser light source so that said stripe pattern formed on said object by said laser light is divided at equal intervals on said measurement plane perpendicular to said optical axis of said image pickup means;

wherein said shape computing means computes position coordinates in a spatial coordinate system from said image data and deflection angle data to decide the shape of said object.

7. A shape measuring device according to claim 6, wherein said flash timing means decides the flash pattern providing the equal intervals of said stripe pattern on said measurement plane from said image data obtained by said image pickup means when measurement is made on said measurement plane in a condition where said object is absent on said measurement plane.

8. A shape measuring device according to claim 7, further comprising:

flash pattern changing means for changing the flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

9. A shape measuring device according to claim 8, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

10. A shape measuring device according to claim 6, further comprising:

flash pattern changing means for changing the flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

11. A shape measuring device according to claim 10, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

12. A shape measuring device according to claim 4, further comprising:

flash timing means for controlling the flashing of said laser light from said laser light source so that said stripe pattern formed on said object by said laser light is divided at equal intervals on said measurement plane perpendicular to said optical axis of said image pickup means;

wherein said shape computing means computes position coordinates in a spatial coordinate system from said image data and deflection angle data to decide the shape of said object.

13. A shape measuring device according to claim 12, wherein said flash timing means decides the flash pattern providing the equal intervals of said stripe pattern on said measurement plane from said image data obtained by said image pickup means when measurement is made on said measurement plane in a condition where said object is absent on said measurement plane.

14. A shape measuring device according to claim 13, further comprising:

flash pattern changing means for changing the flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

15. A shape measuring device according to claim 14, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

16. A shape measuring device according to claim 12, further comprising:

flash pattern changing means for changing the flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

17. A shape measuring device according to claim 16, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

18. A shape measuring device according to claim 4, wherein said scanning device comprises a galvanomirror.

19. A shape measuring device according to claim 1, further comprising:

binarizing means for binarizing said image data obtained by said image pickup means;

storing means for storing said image data binarized by said binarizing means as space code data;

updating means for performing logic operation between data newly supplied from said binarizing means and data already stored in said storing means to thereby update storage contents of said storing means; and

coordinate data generating means for generating coordinate data according to positions on a pickup plane of said image pickup means;

wherein said shape computing means computes the shape of said object according to said space code data and said coordinate data.

20. A shape measuring device according to claim 1, further comprising:

binarizing means for binarizing said image data obtained by said image pickup means;

storing means for storing said image data binarized by said binarizing means as space code data;

coordinate data generating means for generating coordinate data according to positions on a pickup plane of said image pickup means; and

converting means preliminarily storing height values corresponding to all space code data and all coordinate data;

wherein said shape computing means reads said height values from said converting means according to said space code data and said coordinate data to thereby compute the shape of said object.

21. A shape measuring device according to claim 20, further comprising:

updating means for performing logic operation between data newly supplied from said binarizing means and data already stored in said storing means to thereby update storage contents of said storing means.

22. A shape measuring device having a laser light source for generating flashing laser light, a lens system for shaping said laser light into a slit-shaped beam, a scanning device for deflecting said laser light shaped into said slit-shaped beam toward an object placed on a measurement plane to scan said object, and image pickup means for picking up a stripe pattern formed on said object by scanning said laser light, said shape measuring device comprising:

driving means for generating a drive signal to drive said scanning device so that the scanning of said laser light by said scanning device over a measurement range is performed at least once in a pickup time per frame of said image pickup means;

drive timing means for adjusting generation of the drive signal by said driving means so as to correct a nonlinear relation between said drive signal and deflection angle data indicative of an actual deflection angle of said scanning device;

generating means for generating space code data from image data obtained by said image pickup means; and

shape computing means for computing a shape of said object from the space code data and the deflection angle data.

23. A shape measuring device according to claim 22, wherein said drive timing means calculates a correction quantity for said drive signal from said image data obtained by said image pickup means when measurement is made on said measurement plane perpendicular to an optical axis of said image pickup means in a condition where said object is absent on said measurement plane.

24. A shape measuring device according to claim 23, further comprising:

flash timing means for controlling the flashing of said laser light from said laser light source so that said stripe pattern formed on said object by said laser light is divided at equal intervals on said measurement plane perpendicular to said optical axis of said image pickup means;

wherein said shape computing means computes position coordinates in a spatial coordinate system from said image data and the deflection angle data to decide the shape of said object.

25. A shape measuring device according to claim 24, wherein said flash timing means decides a flash pattern providing the equal intervals of said stripe pattern on said measurement plane from said image data obtained by said image pickup means when measurement is made on said measurement plane in a condition where said object is absent on said measurement plane.

26. A shape measuring device according to claim 25, further comprising:

flash pattern changing means for changing the flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

27. A shape measuring device according to claim 26, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

28. A shape measuring device according to claim 24, further comprising:

flash pattern changing means for changing a flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

29. A shape measuring device according to claim 28, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

30. A shape measuring device according to claim 22, further comprising:

flash timing means for controlling the flashing of said laser light from said laser light source so that said stripe pattern formed on said object by said laser light is divided at equal intervals on said measurement plane perpendicular to an optical axis of said image pickup means;

wherein said shape computing means computes position coordinates in a spatial coordinate system from said image data and the deflection angle data to decide the shape of said object.

31. A shape measuring device according to claim 30, wherein said flash timing means decides a flash pattern providing the equal intervals of said stripe pattern on said measurement plane from said image data obtained by said image pickup means when measurement is made on said measurement plane in a condition where said object is absent on said measurement plane.

32. A shape measuring device according to claim 31, further comprising:

flash pattern changing means for changing the flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

33. A shape measuring device according to claim 32, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

34. A shape measuring device according to claim 30, further comprising:

flash pattern changing means for changing a flash pattern of said laser light from said laser light source every time the scanning is performed; and

image data storing means capable of storing plural frames of image data obtained by said image pickup means;

wherein said shape computing means computes the shape of said object according to said plural frames of image data picked up with different flash patterns.

35. A shape measuring device according to claim 34, wherein said flash pattern changing means changes the flash pattern of said laser light from said laser light source according to a gray code.

36. A shape measuring device according to claim 22, wherein said scanning device comprises a galvanomirror.

37. A shape measuring device having a laser light source for generating flashing laser light, a scanning device for deflecting said laser light toward an object placed on a measurement plane to scan said object, and image pickup means for picking up image data formed on said object by scanning said laser light, said shape measuring device comprising:

binarizing means for binarizing said image data obtained by said image pickup means;

storing means for storing said image data binarized by said binarizing means as space code data;

updating means for performing a logic operation between image data newly supplied from said binarizing means and image data already stored in said storing means to thereby update storage contents of said storing means;

coordinate data generating means for generating coordinate data according to positions on a pickup plane of said image pickup means; and

computing means for computing height values for the object from said space code data and said coordinate data.

38. A shape measuring device having a laser light source for generating flashing laser light, a scanning device for deflecting said laser light toward an object placed on a measurement plane to scan said object, and image pickup means for picking up image data formed on said object by scanning said laser light, said shape measuring device comprising:

binarizing means for binarizing said image data obtained by said image pickup means;

storing means for storing said image data binarized by said binarizing means as space code data;

coordinate data generating means for generating coordinate data according to positions on a pickup plane of said image pickup means;

converting means preliminarily storing height values corresponding to all of the space code data and all of the coordinate data; and

shape computing means for reading said height values from said converting means according to said space code data and said coordinate data to thereby compute the shape of said object.

39. A shape measuring device according to claim 38, further comprising:

updating means for performing logic operation between data newly supplied from said binarizing means and data already stored in said storing means to thereby update storage contents of said storing means.