Method and apparatus for detecting a workpiece, and method and apparatus for inspecting a workpiece

• US 20050058333A1
• Filed: 02/21/2003
• Published: 03/17/2005
• Est. Priority Date: 02/21/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Bridgestone, Micron Technology, Inc.
• Original Assignee: Kabushiki Kaisha Bridgestone
• Inventors: Kaneko, Tomoyuki, Kokubu, Takao
• Granted Patent: US 7,421,108 B2
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01B 11/2522 the position of the object changing and being recorded
• CPC Class Codes: G01M 17/027 using light, e.g. infrared, ultraviolet or holographic techniques
• 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 21/95 characterised by the material or shape of the object to be examined G01N21/89 - G01N21/91, G01N21/94 take precedence
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A tire T as a workpiece mounted on a rotary table 2 is imaged by using floodlight means 10 for applying white slit light and a color CCD camera 20 for imaging a portion illuminated by the slit light while it is turned, the coordinates and brightness of the tire T are detected from the obtained image data by coordinate computing means 31 and brightness computing means 33, and the 3-D coordinate data and color image of the tire T are re-formed from the obtained shape data and brightness data of the tire T by shape image forming means 32 and appearance image forming means 34 and compared with tire appearance and shape data prestored in tire information storage means 35 to judge whether the appearance and shape of the tire T are acceptable or not.

Claims

1. A method of detecting a workpiece, comprising the steps of:

moving a workpiece, floodlight means for applying slit light to the surface to be inspected of the workpiece and imaging means having an area camera for imaging a portion illuminated by the slit light relative to one another to image the workpiece; and

detecting the coordinates and brightness of the workpiece from the pixel data of the area camera.

7. The method of inspecting a workpiece according to claim 1, wherein white slit beams and a color camera are used to detect the shape and color of the workpiece at the same time.

2. A method of inspecting a workpiece, comprising the steps of:

moving a workpiece, floodlight means for applying slit light to the surface to be inspected of the workpiece and imaging means having an area camera for imaging a portion illuminated by the slit light relative to one another to image the workpiece; and

inspecting the workpiece based on the coordinates and brightness of the workpiece calculated from the pixel data of the area camera.

3. The method of inspecting a workpiece according to claim 2, wherein the coordinates and brightness of a specific region of the workpiece are integrated to obtain the shape data and density data of the specific region.

4. The method of inspecting a workpiece according to claim 2, wherein the obtained shape data or density data is compared with the reference shape data or reference density data on the specific region of the workpiece to inspect the workpiece.

5. The method of inspecting a workpiece according to claim 4, wherein it is judged that the specific region of the workpiece is unacceptable when the size of a region in which the difference between the obtained shape data and reference shape data and/or the difference between the obtained density data and reference density data exceeds a preset threshold value becomes larger than a predetermined value.

6. The method of inspecting a workpiece according to claim 2, wherein the workpiece is inspected based on surface unevenness calculated from the obtained shape data or the degree of density calculated from the obtained density data.

11. The method of inspecting a workpiece according to claim 3, wherein the obtained shape data or density data is compared with the reference shape data or reference density data on the specific region of the workpiece to inspect the workpiece.

12. The method of inspecting a workpiece according to claim 3, wherein the workpiece is inspected based on surface unevenness calculated from the obtained shape data or the degree of density calculated from the obtained density data.

13. The method of inspecting a workpiece according to claim 2, wherein white slit beams and a color camera are used to detect the shape and color of the workpiece at the same time.

14. The method of inspecting a workpiece according to claim 3, wherein white slit beams and a color camera are used to detect the shape and color of the workpiece at the same time.

15. The method of inspecting a workpiece according to claim 4, wherein white slit beams and a color camera are used to detect the shape and color of the workpiece at the same time.

16. The method of inspecting a workpiece according to claim 5, wherein white slit beams and a color camera are used to detect the shape and color of the workpiece at the same time.

17. The method of inspecting a workpiece according to claim 6, wherein white slit beams and a color camera are used to detect the shape and color of the workpiece at the same time.

8. An apparatus for detecting a workpiece, comprising:

floodlight means for applying slit light to the surface to be inspected of the workpiece;

an area camera for imaging a portion illuminated by the slit light;

means of moving the floodlight means, the imaging means and the workpiece relative to one another;

means of calculating the coordinates of the workpiece from the pixel data of the area camera;

means of calculating the brightness of the workpiece from the pixel data of the area camera; and

means of detecting the appearance of the workpiece based on the calculated brightness.

9. The apparatus for detecting a workpiece according to claim 8, wherein white light is used as the slit light and a color camera is used as the imaging means.

10. An apparatus for inspecting a workpiece, comprising:

the appearance and shape detection apparatus of claim 8;

means of storing reference data on the appearance and shape of the workpiece; and

means of judging whether the shape and appearance of the workpiece are acceptable or not by comparing data on the appearance and shape of the workpiece obtained by the appearance and shape detection apparatus with the reference data.

18. An apparatus for inspecting a workpiece, comprising:

the appearance and shape detection apparatus of claim 9;

means of storing reference data on the appearance and shape of the workpiece; and

means of judging whether the shape and appearance of the workpiece are acceptable or not by comparing data on the appearance and shape of the workpiece obtained by the appearance and shape detection apparatus with the reference data.