Flaw detection in objects and surfaces

• US 20040150815A1
• Filed: 02/05/2003
• Published: 08/05/2004
• Est. Priority Date: 02/05/2003
• Status: Abandoned Application

• Current Assignee: Applied Vision Company, LLC
• Original Assignee: Applied Vision Company, LLC
• Inventors: Sones, Richard Allen, Novini, Amir Reza
• Application Number:
  US10/359,117
• Publication Number:
  US 20040150815A1
• Time in Patent Office: Days
• US Class Current: 356/239.4
• CPC Class Codes: G01N 2021/8825 Separate detection of dark field and bright field
• CPC Class Codes: G01N 2021/8907 Cylindrical optics
• CPC Class Codes: G01N 21/9054 Inspection of sealing surface and container finish

Abstract

The invention relates generally to the simultaneous acquisition of superimposed color dark-field and light-field images with a camera followed by decoupling of the images into monochrome components for further analysis of surface defects.

Claims

1. A machine vision inspection method comprising the steps of:

(a) illuminating an area to be inspected with a first illuminator by emitting light of a first color, said first illuminator providing light-field illumination of said area;

(b) illuminating said area with a second illuminator emitting light of a second color, said second illuminator providing dark-field illumination of said area, said first and second color light being of different bands of wavelengths;

(c) acquiring a color image of said area while said area is illuminated with both said first and said second illuminators;

(d) processing data within said color image to detect flaws in said area.

2. The method of claim 1 further comprising the steps of:

(a) generating a first monochrome image from said color image, said first monochrome image corresponding to the brightness of said first color within said color image;

(b) generating a second monochrome image from said color image, said second monochrome image corresponding to the brightness of said second color within said color image;

(c) processing data within said first monochrome image and said second monochrome image to detect flaws in said area.

3. The method of claim 2 further comprising the steps of:

(a) processing data within said first monochrome image in order to determine the position of said area within said first monochrome image;

(b) using said position to guide further processing of data within said first monochrome image to detect flaws in said area.

4. The method of claim 3 which further comprises the step of:

(a) using said position to guide further processing of data within said second monochrome image to detect flaws in said area.

5. The method of claim 4 which further comprises the step of:

(a) using said position to guide further processing of data within both said first monochrome image and said second monochrome image.

6. The method of claim 3 wherein

(a) said steps of illuminating occur substantially simultaneously.

7. The method of claim 6 wherein

(a) said steps of illuminating are strobed in association with a detection of said area to be inspected by an area-present sensor.

8. The method of claim 7 wherein

(a) said area-present sensor is a photoelectric cell.

9. The method of claim 1 wherein

(a) said step of processing data comprises using a color filter array selected from the group consisting of red, green, blue and cyan, magenta, yellow.

10. The method of claim 1 wherein

(a) said step of processing data comprises using a multi-spectral array.

11. A machine vision inspection method comprising the steps of:

(a) illuminating an area to be inspected with a first illuminator by emitting light of at least a first color, said first illuminator providing light-field illumination of said area;

(b) illuminating said area with a second illuminator emitting light of at least a second color, said second illuminator providing dark-field illumination of said area, said first and second color light being of different bands of wavelengths;

(c) acquiring a color image of said area while said area is illuminated with both said first and said second illuminators;

(d) processing data within said color image to detect flaws in said area.

12. The method of claim 11 further comprising the steps of:

(a) generating a first monochrome image from said color image, said first monochrome image corresponding to the brightness of said first color within said color image;

(b) generating a second monochrome image from said color image, said second monochrome image corresponding to the brightness of said second color within said color image;

(c) processing data within said first monochrome image and said second monochrome image to detect flaws in said area.

13. The method of claim 12 further comprising the steps of:

(a) processing data within said first monochrome image in order to determine the position of said area within said first monochrome image;

(b) using said position to guide further processing of data within said first monochrome image to detect flaws in said area.

14. The method of claim 13 which further comprises the step of:

(a) using said position to guide further processing of data within said second monochrome image to detect flaws in said area.

15. The method of claim 14 which further comprises the step of:

(a) using said position to guide further processing of data within both said first monochrome image and said second monochrome image.

16. The method of claim 13 wherein

(a) said steps of illuminating occur substantially simultaneously.

17. The method of claim 16 wherein

(a) said steps of illuminating are strobed in association with a detection of an area to be inspected by an area-present sensor.

18. The method of claim 17 wherein

(a) said area-present sensor is a photoelectric cell.

19. The method of claim 11 wherein

(a) said step of processing data comprises using a color filter array selected from the group consisting of red, green, blue and cyan, magenta, yellow.

20. The method of claim 11 wherein

(a) said step of processing data comprises using a multi-spectral array.

21. A machine vision inspection method comprising the steps of:

(a) illuminating an area to be inspected with a first and second illuminator, said illuminators emitting a first and second color light of different bands of wavelengths;

(b) acquiring a color image of said area while said area is illuminated with both said first and said second illuminators;

(c) processing data within said color image to detect flaws in said area.

22. The method of claim 21 further comprising the steps of:

(a) generating a first monochrome image from said color image, said first monochrome image corresponding to the brightness of said first color within said color image;

(b) generating a second monochrome image from said color image, said second monochrome image corresponding to the brightness of said second color within said color image;

(c) processing data within said first monochrome image and said second monochrome image to detect flaws in said area.

23. The method of claim 22 further comprising the steps of:

(a) processing data within said first monochrome image in order to determine the position of said area within said first monochrome image;

(b) using said position to guide further processing of data within said first monochrome image, such further processing designed to detect flaws in said area.

24. The method of claim 23 which further comprises the step of:

(a) using said position to guide further processing of data within said second monochrome image to detect flaws in said area.

25. The method of claim 24 which further comprises the step of:

(a) using said position to guide further processing of data within both said first monochrome image and said second monochrome image.

26. The method of claim 23 wherein

(a) said steps of illuminating occur substantially simultaneously.

27. The method of claim 26 wherein

(a) said steps of illuminating are strobed in association with a detection of an area to be inspected by an area-present sensor.

28. The method of claim 27 wherein

(a) said part-present sensor is a photoelectric cell.

29. The method of claim 21 wherein

(a) said step of processing data comprises using a color filter array selected from the group consisting of red, green, blue and cyan, magenta, yellow.

30. The method of claim 21 wherein

(a) said step of processing data comprises using a multi-spectral array.

31. A machine vision inspection method comprising the steps of

(a) illuminating an area to be inspected with at least three means for emitting light, each means of different bands of wavelengths;

(b) acquiring a color image of said area while said area is illuminated;

(c) processing data within said color image to detect flaws in said area.

32. The method of claim 31 further comprising the steps of:

(a) generating three monochrome images from said color image, each of said monochrome images corresponding to the brightness of said different bands of wavelengths within said color image;

(b) processing data within said monochrome images to detect flaws in said area.

33. The method of claim 32 wherein

(a) said step of illuminating further comprises at least one illuminator being configured to provide light-field illumination of said area.

34. The method of claim 33 wherein

(a) said step of illuminating further comprises at least one illuminator being configured to provide dark-field illumination of said area.

35. The method of claim 32 further comprising the steps of:

(a) processing data within said first monochrome image obtained from said at least one illuminator configured to provide light-field illumination in order to determine the position of said area within said first monochrome image;

(b) using said position to guide further processing of data within said first monochrome image, such further processing designed to detect flaws in said area.

36. The method of claim 35 which further comprises the step of:

(a) using said position to guide further processing of data within said second and third monochrome images to detect flaws.

37. The method of claim 36 wherein

(a) said steps of illuminating occur substantially simultaneously.

38. The method of claim 37 wherein

(a) said steps of illuminating are strobed in association with a detection of an area to be inspected by an area-present sensor.

39. The method of claim 38 wherein

(a) said area-present sensor is a photoelectric cell.

40. The method of claim 31 wherein

(a) said step of processing data comprises using a color filter array selected from the group consisting of red, green, blue and cyan, magenta, yellow.

41. The method of claim 40 wherein

(a) said step of processing data comprises using a multi-spectral array.

42. An apparatus which comprises:

(a) a first means for emitting light of a first color to provide light-field illumination of an area;

(b) a second means for emitting light of a second color to provide dark-field illumination of said area, said first and second color light being of different bands of wavelengths;

(c) a means for area-present detection which strobes said means for predetermined intervals;

(d) a color image acquisition means for acquiring a color image of said area while said area is simultaneously illuminated;

(e) a processing means for processing data within said color image to detect flaws in said area.

43. The apparatus of claim 42 wherein

(a) said second means for emitting light is low angle directional light.

44. The apparatus of claim 43 wherein

(a) said low angle is between approximately 5 to 30°

.

45. The apparatus of claim 44 wherein

(a) said angle is between approximately 8-22°

.

46. The apparatus of claim 45 wherein

(a) said angle is between approximately 10-18°

.

47. The apparatus of claim 42 wherein

(a) said means for emitting light are LEDs.

48. The apparatus of claim 47 wherein

(a) Said LEDs are selected from the group consisting of infrared, red, orange, yellow, green, blue and ultraviolet LEDs.

49. The apparatus of claim 48 wherein

(a) said first means for emitting light is a green LED, and

(b) said second means for emitting light is a red LED.

50. The apparatus of claim 42 wherein

(a) said area-present means is a photoelectric cell.

51. The apparatus of claim 50 wherein

(a) said first illuminator is selected from the group consisting of hemispherical dome illuminators, cloudy day illuminators and on-axis light illuminators.

52. The apparatus of claim 51 wherein

(a) said second illuminator is a ring illuminator.