Inspection apparatus, inspection method, and program

Patent metadata

Field	Value
Publication number	US-9571817-B2
Application number	US-201514718109-A
Country	US
Kind code	B2
Filing date	May 21, 2015
Priority date	Jun 9, 2014
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A photometric processing part calculates a normal vector of a surface of a workpiece from a plurality of luminance images acquired by a camera in accordance with the photometric stereo method, and performs synthesis processing of synthesizing at least two images out of an inclination image made up of pixel values based on the normal vector calculated from the plurality of luminance images and at least one reduced image of the inclination image, to generate an inspection image showing a surface shape of the inspection target. In particular, a characteristic size setting part sets a characteristic size which is a parameter for giving weight to a component of a reduced image at the time of performing the synthesis processing. The photometric processing part can generate a different inspection image in accordance with the set characteristic size.

First claim

What is claimed is:

1. An inspection apparatus comprising:
an illumination section for illuminating an inspection target in accordance with a photometric stereo method;
an imaging section for receiving reflective light from the illuminated inspection target to generate a luminance image in accordance with the photometric stereo method;
a computing section for calculating a normal vector of a surface of the inspection target from a plurality of luminance images acquired by the imaging section, generating an inclination image made up of pixel values based on the normal vector calculated from the plurality of luminance images and at least one reduced image of the inclination image, and performing synthesis processing of synthesizing at least two images out of the inclination image and the at least one reduced image, to generate an inspection image showing a surface shape of the inspection target;
a determination section for determining defectiveness/non-defectiveness of the inspection target by using the inspection image; and
a setting section for setting a characteristic size which is a parameter for giving weight to a component of the reduced image at the time of performing the synthesis processing,
wherein the computing section generates a different inspection image in accordance with the characteristic size set by the setting section.

2. The inspection apparatus according to claim 1 , wherein the computing section generates a plurality of reduced images using different reduction ratios.

3. The inspection apparatus according to claim 1 , wherein, when the characteristic size is changed by the setting section, the computing section changes the characteristic size with respect to the acquired inclination image without re-imaging by the imaging section, to update the inspection image.

4. The inspection apparatus according to claim 1 , wherein the setting section sets different characteristic sizes in a stepwise manner corresponding to an inspection application.

5. The inspection apparatus according to claim 1 , wherein
the setting section sets a plurality of characteristic sizes with respectively different values, and
the computing section generates the inspection image with respect to each of the plurality of characteristic sizes set by the setting section.

6. The inspection apparatus according to claim 1 , further comprising
a flaw inspection section for executing flaw inspection on a plurality of inspection images generated by using respectively different characteristic sizes,
wherein the determination section determines defectiveness/non-defectiveness of the inspection target by using a result of the inspection by the flaw inspection section.

7. The inspection apparatus according to claim 1 , further comprising
a character recognizing section for performing character recognition processing on a plurality of inspection images generated by using respectively different characteristic sizes,
wherein the determination section determines defectiveness/non-defectiveness of the inspection target by using a result of the character recognition by the character recognizing section.

8. The inspection apparatus according to claim 1 , wherein
the computing section calculates a reflectance of the surface of the inspection target along with a normal vector of the surface of the inspection target from a plurality of luminance images acquired by the imaging section, to generate a reflectance image whose pixel value is the reflectance, and
the determination section determines defectiveness/non-defectiveness of the inspection target by using the reflectance image.

9. The inspection apparatus according to claim 1 , wherein
the computing section generates an inclination image made up of pixel values based on a normal vector of the surface of the inspection target from a plurality of luminance images acquired by the imaging section, and
the determination section determines defectiveness/non-defectiveness of the inspection target by using the inclination image.

10. The inspection apparatus according to claim 1 , further comprising
a storage section for storing the inspection image,
wherein the determination section reads the inspection image from the storage section and executes inspection, to determine defectiveness/non-defectiveness of the inspection target based on a result of the inspection.

11. The inspection apparatus according to claim 10 , wherein the storage section stores a plurality of inspection images generated by applying characteristic sizes with respectively different values.

12. The inspection apparatus according to claim 1 , further comprising:
a selection section for selecting one inspection image out of a plurality of inspection images; and
an inspection tool setting section for setting an inspection tool for the inspection image selected by the selection section.

13. The inspection apparatus according to claim 1 , further comprising
an image selection section for selecting an image, which is to be saved or outputted, out of a plurality of luminance images acquired by the imaging section and the inspection image.

14. The inspection apparatus according to claim 13 , wherein the image selection section selects an image, which is to be saved or outputted, out of the plurality of luminance images, the inspection image, a luminance image acquired by lighting all of the plurality of light sources provided in the illumination sections, and a synthesized luminance image obtained by synthesizing the plurality of luminance images.

15. The inspection apparatus according to claim 13 , wherein the image selection section selects an image, which is to be saved or outputted, out of the plurality of inspection images with respectively different characteristic sizes.

16. The inspection apparatus according to claim 13 , wherein the image selection section selects an image, which is to be saved or outputted, out of the plurality of luminance images, the inspection image, and a reflectance image whose pixel value is a reflectance of the surface of the inspection target.

17. The inspection apparatus according to claim 13 , further comprising
a condition setting section for setting a condition for saving or outputting an image.

18. The inspection apparatus according to claim 17 , wherein the condition setting section sets one of a mode for constantly saving or outputting an image and a mode for saving or outputting an image when the determination section determines that the inspection target is not a non-defective product.

19. A computer storing a program that causes the computer as:
an illumination section for illuminating an inspection target in accordance with a photometric stereo method;
an imaging section for receiving reflective light from the illuminated inspection target to generate a luminance image in accordance with the photometric stereo method;
a computing section for calculating a normal vector of a surface of the inspection target from a plurality of luminance images acquired by the imaging section, and performing synthesis processing of synthesizing at least two images out of an inclination image made up of pixel values based on the normal vector calculated from the plurality of luminance images and at least one reduced image of the inclination image, to generate an inspection image showing a surface shape of the inspection target;
a determination section for determining defectiveness/non-defectiveness of the inspection target by using the inspection image; and
a setting section for setting a characteristic size

Assignees

• Keyence Co Ltd

Inventors

• Mayumi Norimasa

Classifications

• H04N23/56

  provided with illuminating means · CPC title

• G06T7/0004

  Industrial image inspection · CPC title

• G01N21/8803

  Visual inspection (measuring projectors G01B9/08) · CPC title

• G01N2201/06

  Illumination; Optics · CPC title

• G06T7/0073

  Physics · mapped topic