Board inspection apparatus and method and apparatus for setting inspection logic thereof

• US 7,720,274 B2
• Filed: 03/16/2006
• Issued: 05/18/2010
• Est. Priority Date: 03/17/2005
• Status: Expired due to Fees

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Katahata, Takatoshi, Shimizu, Atsushi, Nakajima, Akira, Moriya, Toshihiro, Wada, Hirotaka
• Primary Examiner(s): Ahmed; Samir A.
• Assistant Examiner(s): HU, FRED H.
• Application Number:
  US11/377,938
• Publication Number:
  US 20060257015A1
• Time in Patent Office: 1,524 Days
• Field of Search: None
• US Class Current: 382/145
• CPC Class Codes: G06T 2207/30141 Printed circuit board [PCB]
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 2207/30152 Solder
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

In generating inspection logic of a new component, the image of a new component is obtained, the trend data for selected characteristics of the focused region of the new component is computed; a previously inspected component having characteristics similar to that of the new component is selected by comparing the trend data of the new component with trend data of the previously inspected component, the image of the selected (previously inspected) component is read from the storage device, and inspection logic for the new component is generated using the images of the new component and images of the previously inspected component as teaching data.

Claims

1. A method of generating inspection logic used in board inspection, the board inspection determining whether a surface-mounted state of a new component is acceptable or defective by checking a color of a focused region in an inspection image of the board surface-mounted new component, the method comprising:

storing a reference image of each of a plurality of previously inspected components in a storage device of an information processing apparatus;

computing color distribution trend data which indicates a color distribution trend of a focused region in each of the reference images of the previously inspected components;

obtaining the image of the new component;

computing color distribution trend data which indicates the color distribution trend of the focused region in the inspection image of the new component;

selecting the previously inspected component having the color distribution trend similar to that of the new component by comparing the color distribution trend data concerning the new component and the color distribution trend data concerning the previously inspected component;

reading the image of the selected previously inspected component from the storage device; and

generating the inspection logic of the new component using the inspection image of the new component and the reference image of the read previously inspected component as teaching data;

wherein the color distribution trend data is computed based on a distribution on a color space of a color characteristic amount value obtained from a pixel of the focused region, and

wherein the method is performed by the information processing apparatus.

2. An inspection logic setting method according to claim 1, wherein the inspection image of the new component is formed only by an acceptable image, only by a defective image, or by both the acceptable image and the defective image, and

the reference image of the previously inspected component is formed by both the acceptable image and the defective image.

3. An inspection logic setting method according to claim 1, wherein a kind of the component is also stored in the storage device, and

an information processing device selects the component having the similar color distribution trend from the previously inspected components having the kind common to the new component and the previously inspected component.

4. An inspection logic setting method according to claim 1, wherein the color distribution trend data is data in which the distribution of the color characteristic amount value obtained from the pixel of the focused region is expressed by combination of blocks partitioning the color space.

5. An inspection logic setting method according to claim 1, wherein the kind of the color characteristic amount used in computing the color distribution trend data is a color characteristic amount which is selected such that a difference is generated between a distribution of the color characteristic amount value obtained from the pixel of the focused region in an acceptable image and a distribution of the color characteristic amount value obtained from the pixel of the focused region in a defective image.

6. An inspection logic setting method according to claim 1, further comprising:

determining a frequency distribution of the color characteristic amount value of each of a target point and an exclusion point for one or a plurality of color characteristic amount values, assuming that each pixel of the focused region in an acceptable image is set at a target point in the teaching data and each pixel of the focused region in a defective image is set at an exclusion point in the teaching data;

determining a range of the color characteristic amount value, which best separates the color characteristic amount value of the target point and the color characteristic amount value of the exclusion point, based on the frequency distribution of the one or plurality of color characteristic amount values; and

setting a kind and a value range of the one or plurality of color characteristic amounts at a color condition for extracting a specific color region from the focused region in the inspection image of the component to be inspected.

7. An inspection logic setting method according to claim 6, further comprising:

extracting a pixel region satisfying the color condition from each of the focused region in the acceptable image in the teaching data and the focused region in the defective image in the teaching data;

determining a frequency distribution of a characteristic amount value of each of the plurality of pixel regions for the one or plurality of characteristic amount concerning the extracted pixel region;

determining a range of the characteristic amount value, which best separates the characteristic amount value of the target point and the characteristic amount value of the exclusion point, based on the frequency distribution of the one or plurality of characteristic amount values; and

setting the kind and the value range of the one or plurality of characteristic amounts at a determination condition for determining whether the surface-mounted state of the component to be inspected is acceptable or defective.

14. A board inspection apparatus comprising:

a storage unit in which a color condition and a determination condition are stored, the color condition and the determination condition being generated by a inspection logic generating method according to claim 7;

a floodlighting device which illuminates a surface-mounted component on a board with light beams of a plurality of colors at different incident angles;

a region extracting device which extracts a region satisfying the color condition from a focused region of an image taken with a reflected light beam; and

an inspection device which determines the surface-mounted state of the component based on whether or not a characteristic amount possessed by the extracted region satisfies the determination condition.

8. An apparatus for generating inspection logic used in board inspection, the board inspection determining whether a surface-mounted state of a new component is acceptable or defective by checking a color of a focused region in an inspection image of a board surface-mounted component, the apparatus comprising:

a storage device in which a reference image of a previously inspected component is stored;

an image obtaining device which obtains an inspection image of the new component;

a color distribution trend computing device which computes both color distribution trend data for indicating a color distribution trend of the focused region in the inspection image of the new component and color distribution trend data for indicating the color distribution trend of the focused region in the reference image of the previously inspected component;

a similarity component selecting device which selects the previously inspected component having the color distribution trend similar to that of the new component by comparing the color distribution trend data concerning the new component and the color distribution trend data concerning the previously inspected component;

a teaching data generating device which reads the image of the selected previously inspected component from the storage device to generate teaching data from the inspection image of the new component and the reference image of the previously inspected component; and

an inspection logic generating device which generates the inspection logic from the teaching data,

wherein the color distribution trend data computing device computes the color distribution trend data based on a distribution on a color space of a color characteristic amount value obtained from a pixel of the focused region.

9. An inspection logic setting apparatus according to claim 8, wherein a kind of the component is also stored in the storage device, and

the similarity component selecting device selects the component having the similar color distribution trend from the previously inspected components having the kind common to the new component and the previously inspected component.

10. An inspection logic setting apparatus according to claim 8, wherein the color distribution trend data computing device expresses the distribution of the color characteristic amount value obtained from the pixel of the focused region by combination of blocks partitioning the color space.

11. An inspection logic setting apparatus according to claim 8, wherein the color distribution trend computing device selects the color characteristic amount as the kind of the color characteristic amount used in computing the color distribution trend data such that a difference is generated between a distribution of the color characteristic amount value obtained from the pixel of the focused region in an acceptable image and a distribution of the color characteristic amount value obtained from the pixel of the focused region in a defective image.

12. An inspection logic setting apparatus according to claim 8, wherein the inspection logic generating device constituting an inspection logic apparatus includes:

a device which determines a frequency distribution of the color characteristic amount value of each of a target point and an exclusion point for one or a plurality of color characteristic amount values, assuming that each pixel of the focused region in the acceptable image is set at a target point in the teaching data and each pixel of the focused region in the defective image is set at an exclusion point in the teaching data;

a device which determines a range of the color characteristic amount value, which best separates the color characteristic amount value of the target point and the color characteristic amount value of the exclusion point, based on the frequency distribution of the one or plurality of color characteristic amount values; and

a device which sets kinds and value ranges of the one or plurality of color characteristic amounts at a color condition for extracting a specific color region from the focused region in the image of the component to be inspected.

13. An inspection logic setting apparatus according to claim 12, wherein the inspection logic generating device further includes:

a device which extracts a pixel region satisfying the color condition from each of the focused region in the acceptable image in the teaching data and the focused region in the defective image in the teaching data;

a device which determines a frequency distribution of a characteristic amount value of each of the plurality of pixel regions for the one or plurality of characteristic amount concerning the extracted pixel region;

a device which determines a range of the characteristic amount value, which best separates the characteristic amount value of the target point and the characteristic amount value of the exclusion point, based on the frequency distribution of the one or plurality of characteristic amount values; and

a device which sets the kind and the value range of the one or plurality of characteristic amounts at a determination condition for determining whether the surface-mounted state of the component to be inspected is acceptable or defective.