Visual inspection apparatus and visual inspection method

• US 8,976,242 B2
• Filed: 10/01/2008
• Issued: 03/10/2015
• Est. Priority Date: 10/03/2007
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Aikawa, Tetsuro, Satoh, Yoshinori, Ochiai, Makoto, Oodake, Tatsuya, Yuguchi, Yasuhiro, Adachi, Hiroyuki, Takabayashi, Junichi
• Primary Examiner(s): Czekaj, Dave
• Assistant Examiner(s): LI, TRACY Y
• Application Number:
  US12/681,625
• Publication Number:
  US 20100283847A1
• Time in Patent Office: 2,351 Days
• Field of Search: 348/82
• US Class Current: 348/142
• CPC Class Codes: G01N 21/8803 Visual inspection measuring projectors G01B9/08
• 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: G06T 3/4069 by subpixel displacements
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G21C 17/003 Remote inspection of vessels, e.g. pressure vessels
• CPC Class Codes: G21C 17/08 Structural combination of reactor core or moderator structure with viewing means, e.g. with television camera, periscope, window
• CPC Class Codes: G21F 7/02 Observation devices permitting vision but shielding the observer optical systems per se G02
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

The present invention includes a camera which takes an image of a camera or an inspection target; a device which estimates the movement of the inspection target; a device which generates a high resolution image having a higher resolution than the pixel resolution of a video image taken by the camera from the video image taken by the camera; a device which evaluates the quality of the high resolution image generated by the generation device; and a device which presents an inspector who visually inspects the inspection target with the high resolution image together with the quality evaluation result of the high resolution image. The present invention can improve the reliability of inspection by use of the high resolution image as well as can reduce the inspection time, and further can guarantee the reliability of the inspection using a high resolution image.

Claims

1. A visual inspection apparatus, comprising:

an image input device which feeds a video image of an inspection target and outputs a digital data image;

an image selection device which selects an inspection image to be used for inspection based on a feature quantity of images outputted from the image input device;

a high resolution image creation device which generates a high resolution image having a higher resolution than the resolution of the inspection image from the inspection image by performing image alignment of a plurality of selected inspection images and estimating brightness of the high resolution image; and

an image output device which displays the inspection image and the high resolution image;

wherein the image selection device selects the inspection image to be used for inspection on the basis of both of a camera movement amount between continuous images and a lighting change state between continuous images;

an image evaluation device which evaluates the quality of the high resolution image generated by the high resolution image creation device;

wherein the image evaluation device evaluates the quality of the high resolution image in such a manner that the image evaluation device sets a local range to each of the high resolution image generated by the high resolution image creation device and the camera image obtained by performing digital processing on the video image taken by the camera, calculates the brightness dispersion of each of the local ranges, and compares between the brightness dispersion of the camera image and the brightness dispersion of the high resolution image.

2. A visual inspection apparatus, comprising:

an image input device which feeds a video image of an inspection target and outputs a digital data image;

an image selection device which selects an inspection image to be used for inspection based on a feature quantity of images outputted from the image input device;

a high resolution image creation device which generates a high resolution image having a higher resolution than the resolution of the inspection image from the inspection image by performing image alignment of a plurality of selected inspection images and estimating brightness of the high resolution image; and

an image output device which displays the inspection image and the high resolution image;

wherein the image selection device selects the inspection image to be used for inspection on the basis of both of a camera movement amount between continuous images and a lighting change state between continuous images;

an image evaluation device which evaluates the quality of the high resolution image generated by the high resolution image creation device;

wherein the image evaluation device evaluates the quality of the high resolution image in such a manner that the image evaluation device generates a converted image by inversely converting the high resolution image generated by the high resolution image creation device to an image having the same resolution as resolution of the camera image obtained by performing digital processing on the video image taken by the camera and compares between the converted image and the camera image.

3. A visual inspection apparatus, comprising:

an image input device which feeds a video image of an inspection target and outputs a digital data image;

an image selection device which selects an inspection image to be used for inspection based on a feature quantity of images outputted from the image input device;

a high resolution image creation device which generates a high resolution image having a higher resolution than the resolution of the inspection image from the inspection image by performing image alignment of a plurality of selected inspection images and estimating brightness of the high resolution image; and

an image output device which displays the inspection image and the high resolution image;

wherein the image selection device selects the inspection image to be used for inspection on the basis of both of a camera movement amount between continuous images and a lighting change state between continuous images;

an image evaluation device which evaluates the quality of the high resolution image generated by the high resolution image creation device;

a projection device which projects a light pattern onto the inspection target,

wherein the image evaluation device compares between a known size of the light pattern which the projection device projects onto the inspection target and a size of the light pattern extracted from the high resolution image generated by the high resolution image creation device to obtain a measurement accuracy and evaluates the quality of the high resolution image based on the measurement accuracy obtained by measurement from the high resolution image.

4. A visual inspection apparatus, comprising:

an image input device which feeds a video image of an inspection target and outputs a digital data image;

an image selection device which selects an inspection image to be used for inspection based on a feature quantity of images outputted from the image input device;

a high resolution image creation device which generates a high resolution image having a higher resolution than the resolution of the inspection image from the inspection image by performing image alignment of a plurality of selected inspection images and estimating brightness of the high resolution image; and

an image output device which displays the inspection image and the high resolution image;

wherein the image selection device selects the inspection image to be used for inspection on the basis of both of a camera movement amount between continuous images and a lighting change state between continuous images;

an image evaluation device which evaluates the quality of the high resolution image generated by the high resolution image creation device;

a test piece of a known size provided near the inspection target,

wherein the image evaluation device uses the test piece so as to compare between the known size of the test piece and a size obtained by measurement from the high resolution image generated by the high resolution image creation device and evaluates the quality of the high resolution image based on the measurement accuracy obtained by a result of comparing the known size and the size obtained by measurement.

5. A visual inspection apparatus, comprising:

a camera which takes an image of an inspection target;

a movement estimation device which estimates movement of the camera or the inspection target by block matching based on brightness dispersion of two images taken by the camera;

a high resolution image creation device which generates a high resolution image, having a higher resolution than the pixel resolution of a video image taken by the camera, based on the video image taken by the camera;

an image evaluation device which evaluates the quality of the high resolution image generated by the high resolution image creation device by respectively setting local ranges with respect to the camera image outputted from the image input device and the high resolution image generated by the high resolution image creation device based on the movement of the camera or the inspection target estimated by the movement estimation device, calculating a brightness dispersion of the local ranges, and evaluating the quality of the high resolution image on the basis of the brightness dispersion of the local ranges; and

an image output device which presents an inspector who visually inspects the inspection target with the high resolution image together with the quality evaluation result of the high resolution image;

wherein the movement estimation device estimates a position of the movement of any one of the camera and the inspection target in such a manner that the movement estimation device obtains an old image and a new image from a plurality of camera images obtained by performing digital processing on each of a plurality of video images taken by the camera, and compares the enlarged images obtained by performing expansion processing on the images by block matching based on a brightness dispersion.

6. A visual inspection apparatus, comprising:

a camera which takes an image of an inspection target;

a movement estimation device which estimates movement of the camera or the inspection target by block matching based on brightness dispersion of two images taken by the camera;

a high resolution image creation device which generates a high resolution image, having a higher resolution than the pixel resolution of a video image taken by the camera, based on the video image taken by the camera;

an image evaluation device which evaluates the quality of the high resolution image generated by the high resolution image creation device by respectively setting local ranges with respect to the camera image outputted from the image input device and the high resolution image generated by the high resolution image creation device based on the movement of the camera or the inspection target estimated by the movement estimation device, calculating a brightness dispersion of the local ranges, and evaluating the quality of the high resolution image on the basis of the brightness dispersion of the local ranges; and

an image output device which presents an inspector who visually inspects the inspection target with the high resolution image together with the quality evaluation result of the high resolution image;

wherein the high resolution image creation device determines pixel brightness of the high resolution image in such a manner that the high resolution image creation device calculates the pixel brightness of the high resolution image as an average value of pixel intensities of a plurality of camera images used to generate the high resolution image and adds the difference in pixel brightness of a central range including the pixels of the high resolution image and a peripheral range including the central range to the average value.