Three-dimensional shape measuring method, and three-dimensional shape measuring apparatus

• US 20040004727A1
• Filed: 06/26/2003
• Published: 01/08/2004
• Est. Priority Date: 07/04/2002
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Nishiki, Ryo, Yanagisawa, Kuniaki
• Granted Patent: US 6,862,097 B2
• Time in Patent Office: Days
• US Class Current: 356/604
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50

Abstract

A three-dimensional shape measuring method and a three-dimensional shape measuring apparatus of excellent measurement accuracy. An optical system comprises a light source, a pattern forming unit which is disposed on the optical axis of the light source to form slit light from the light from the light source, and a projection lens to collect the slit light on the object for measurement. An asymmetric diaphragm having an aperture in which the size in the direction perpendicular to the slit direction is smaller than the size in the slit direction is provided in order to stop the slit light. An image pickup optical system is provided to measure the three-dimensional shape of the object for measurement on the basis of the slit light reflected from the object for measurement.

Claims

1. A three-dimensional shape measuring method using a light-section method, comprising the steps of:

producing a slit light from an optical system having a light source;

stopping said slit light asymmetrically in a slit direction and a direction perpendicular thereto;

projecting said slit light onto an object for measurement;

detecting said slit light as reflected by said object; and

measuring a three-dimensional shape of said object on the basis of said reflected slit light.

2. A three-dimensional shape measuring method according to claim 1, comprising the step of producing a plurality of said slit lights.

3. A three-dimensional shape measuring method according to claim 1, wherein said light source is less coherent than a laser beam.

4. A three-dimensional shape measuring method according to claim 1, wherein said light source is a white light source.

5. A three-dimensional shape measuring method according to claim 1, wherein said stopping step is performed between said producing step and said projecting step.

6. A three-dimensional shape measuring method according to claim 1, wherein said stopping step is performed following said projecting step.

7. A three-dimensional shape measuring method according to claim 1, further comprising the step of reflecting said slit light with a reflector which is disposed for receiving said reflected light from said object.

8. A three-dimensional shape measuring method according to claim 1, further comprising the step of reflecting said slit light with a reflector which is disposed for reflecting said slit light onto said object.

9. A three-dimensional shape measuring method according to claim 1, wherein said detecting step is performed with a single detector.

10. A three-dimensional shape measuring method according to claim 1, wherein said detecting step is performed with a plurality of detectors.

11. A three-dimensional shape measuring apparatus comprising:

an optical system having a light source, a pattern forming unit which is disposed on the optical axis of said light source to form a slit light using the light from said light source, and a projection lens to collect the slit light on an object for measurement;

an asymmetric diaphragm having an aperture to stop said slit light in which the size of the aperture in the slit direction is smaller than the size of the aperture in the direction perpendicular to the slit direction; and

a detection unit which measures a three-dimensional shape of said object for measurement on the basis of said slit light as reflected from said object for measurement.

12. A three-dimensional shape measuring apparatus according to claim 11, wherein said pattern forming unit forms a plurality of slit lights.

13. A three-dimensional shape measuring apparatus according to claim 11, wherein said light source is less coherent than a laser beam.

14. A three-dimensional shape measuring apparatus according to claim 11, wherein said light source is a white light source.

15. A three-dimensional shape measuring apparatus according to claim 11, wherein said asymmetric diaphragm is disposed between said light source and said projection lens.

16. A three-dimensional shape measuring apparatus according to claim 11, wherein said asymmetric diaphragm stops light received from said projection lens.

17. A three-dimensional shape measuring apparatus according to claim 11, further comprising a reflector disposed for receiving said reflected light from said object.

18. A three-dimensional shape measuring apparatus according to claim 11, further comprising a reflector disposed for reflecting said slit light onto said object.

19. A three-dimensional shape measuring apparatus according to claim 11, wherein said detection unit comprises a single detector.

20. A three-dimensional shape measuring apparatus according to claim 11, wherein said detection unit comprises a plurality of detectors.