System and method for measuring object features with coordinated two and three dimensional imaging

• US 6,291,816 B1
• Filed: 06/08/1999
• Issued: 09/18/2001
• Est. Priority Date: 06/08/1999
• Status: Expired due to Term

• Current Assignee: Rudolph Technologies Incorporated (Onto Innovation Inc.)
• Original Assignee: Robotic Vision Systems, Inc. (Acuity Brands, Inc.)
• Inventors: Liu, Kuo-Ching
• Primary Examiner(s): Allen, Stephone B.
• Application Number:
  US09/327,817
• Time in Patent Office: 833 Days
• Field of Search: 250/234-236, 250/559-4-5, 250/559.23, 250/559.31, 250/559.34, 250/559.48, 250/559.49, 356/375, 356/608, 359/201, 359/202
• US Class Current: 250/234
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• 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: G01N 2021/95661 for leads, e.g. position, curvature
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G01N 21/8851 Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002
• CPC Class Codes: G01N 21/95684 Patterns showing highly reflecting parts, e.g. metallic elements

Abstract

A system and method are disclosed for highly efficient imaging of selected object features utilizing, in combination, a 2D imaging subsystem and a 3D imaging subsystem wherein data from the 2D imaging subsystem is used to predetermine areas containing 3D features of interest such that delay attributable to imaging of areas of non-interest for 3D features is minimized.

Claims

1. A method for imaging an object, comprising the steps of:

scanning a selected region of the surface of an object with a 2D optical detector to obtain data corresponding to 2D features of the selected region of the surface;

generating a 2D image from the data corresponding to 2D features of the selected region of the surface;

scanning the selected region of the surface of an object with a 3D optical detector to obtain data corresponding to 3D features of the selected region of the surface; and

generating a 3D image of portions of the selected region of the surface, the portions of the selected region being selected based upon the 2D image previously generated for the selected region.

2. The method of claim 1 wherein the 2D optical detector is a line scan camera.

3. The method of claim 1 wherein the 2D optical detector is an area array camera.

4. The method of claim 1 wherein the 3D optical detector is a PSD.

5. The method of claim 1 wherein the 3D optical detector is a single channel PSD.

6. The method of claim 1 wherein the 3D optical detector is a multi-channel PSD.

7. The method of claim 1 further comprising buffering of 2D image data from more than one selected region of the surface of an object before generating a 3D image of portions of the selected regions.

8. A method for imaging an object, comprising the steps of:

scanning a selected region of the surface of an object with a 2D optical detector to obtain data corresponding to 2D features of the selected region of the surface;

generating a 2D image from the data corresponding to 2D features of the selected region of the surface;

identifying portions of the selected region of the surface which contain features requiring 3D imaging from the 2D image;

scanning identified portions of the selected region of the surface of an object with a 3D optical detector to obtain 3D data corresponding to features of the identified portions of the selected region of the surface; and

generating a 3D image of the identified portions of the selected region of the surface.

9. The method of claim 8 further comprising buffering of 2D image data from more than one selected region of the surface of an object before scanning portions of the selected regions with a 3D optical detector.

10. A system for imaging of objects comprising:

a 2D scanning assembly;

a 3D scanning assembly; and

a controller, the controller having circuitry to direct imaging by the 3D scanning assembly based on analysis of imaging data from the 2D scanning assembly.

11. The system of claim 10 wherein scanning by the 3D scanning assembly is directed based on analysis of imaging data from the 2D scanning assembly.

12. The system of claim 10 wherein the controller has circuitry to direct independently the acquisition and processing of imaging data from either the 2D scanning assembly or the 3D scanning assembly.

13. The system of claim 10 where the 2D scanning assembly and the 3D scanning assembly are coaxially aligned.

14. The system of claim 10 where the 2D scanning assembly and the 3D scanning assembly are non-coaxially aligned.

15. The system of claim 10 where the 2D scanning assembly comprises a line camera.

16. The system of claim 10 where the 2D scanning assembly comprises an area array camera.

17. The system of claim 10 where the 3D scanning assembly comprises a PSD.

18. The system of claim 10 where the 3D scanning assembly comprises a single channel PSD.

19. The system of claim 10 where the 3D scanning assembly comprises a multichannel PSD.