Defect detecting method and apparatus

• US 4,454,542 A
• Filed: 07/23/1982
• Issued: 06/12/1984
• Est. Priority Date: 07/30/1981
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Kirin Techno System
• Original Assignee: Kirin Beer Kabushiki Kaisha
• Inventors: Miyazawa, Takashi
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US06/401,180
• Time in Patent Office: 690 Days
• Field of Search: 358/106, 250/223 B, 356/240, 356/445, 209/526
• US Class Current: 348/127
• 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 21/90 in a container or its contents G01N21/91 takes precedence
• CPC Class Codes: G01N 21/9054 Inspection of sealing surface and container finish

Abstract

In a defect detecting method and apparatus, the image of an object under inspection is formed, the signals of picture elements forming the image is stored, the picture elements signals are accumulated for each of the regions which form parts of the image, the results of the accumulations for regions proximate to each other are compared, and a defect is detected from the result of the comparison.

Claims

1. A defect detecting method comprising the steps of:

(a) receiving light from an object under inspection, to form an image thereof;

(b) dividing said image into a plurality of picture elements;

(c) storing signals of said picture elements in relation to the positions of the corresponding segments of said image;

(d) imaginarily dividing said image into a plurality of regions;

(e) accumulating said picture element signals for each region;

(f) comparing the results of said accumulations of the regions proximate to each other; and

(g) detecting a defect in said object in accordance with the result of said comparison.

2. A method as set forth in claim 1, in which said regions are formed by dividing said image with lines which are imaginarily drawn radially outwardly from the center of said image.

3. A method as set forth in claim 1, in which

said picture element signals are accumulated for each of a first group of regions which are formed by dividing said image with a first group of lines which are imaginarily drawn radially outwardly from the center of said image, and the results of said accumulations of adjacent regions of said first group are compared to each other;

and

said picture element signals are accumulated for each of a second group of regions which are formed by dividing said image with a second group of lines which are imaginarily drawn radially outwardly from the center of said image, said second group of lines being interposed between said first group of lines, and the results of said accumulations of adjacent regions of said second group are compared to each other.

4. A defect detecting method comprising the steps of:

(a) receiving light from an object under inspection, to form an image thereof;

(b) dividing said image into a plurality of picture elements;

(c) storing the signals of the picture elements in relation to the positions of the corresponding segments of said image;

(d) reading the signals of said picture elements in the order in which the corresponding segments in the central area of said image are traversed by a substantially spiral line which is imaginarily drawn on said image;

(e) detecting a defect in said object in accrdance with the mutual relationship between the signal of one of the picture elements and the signal of another picture element read out a little before the reading of the signal of said one of the picture elements;

(f) imaginarily dividing the peripheral part of said image into a plurality of regions;

(g) accumulating the signals of said picture elements for each region;

(h) comparing the results of said accumulations of regions proximate to each other; and

(i) detecting a defect in said object in accordance with the result of said comparison.

5. A method as set forth in claim 4, wherein said object under inspection comprises a bottle and said method is used for detecting a defect in the bottom part of the bottle.

6. A method as set forth in claim 4, in which said regions are formed by dividing said image with lines which are imaginarily drawn radially outwardly from the center of said image.

7. A method as set forth in claim 4, in which

said picture element signals are accumulated for each of a first group of regions which are formed by dividing said image with a first group of lines which are imaginarily drawn radially outwardly from the center of said image, and the results of said accumulations of adjacent regions of said first group are compared to each other;

and

said picture element signals are accumulated for each of a second group of regions which are formed by dividing said image with a second group of lines which are imaginarily drawn radially outwardly from the center of said image, said second group of lines being interposed between said first group of lines, and the results of said accumulations of adjacent regions of said second group are compared to each other.

8. A defect detecting apparatus comprising:

(a) means for receiving light from an object under inspection, to form an image thereof;

(b) means for storing signals of picture elements forming said image in relation to the positions of the corresponding segments of said image;

(c) means for accumulating said picture element signals for each one of the regions which respectively form parts of said image;

(d) means for comparing the results of said accumulations of regions proximate to each other; and

(e) means for detecting a defect in said object under inspection in accordance with the result of said comparison.

9. An apparatus as set forth in claim 8, wherein said means (c) comprises means for accumulating said picture element signals for each one of the regions formed by dividing said image with lines which are imaginarily drawn radially outwardly from the center of said image.

10. An apparatus as set forth in claim 8, wherein said means (c) comprises means for accumulating said picture element signals for each of a first group of regions which are formed by dividing said image with a first group of lines imaginarily drawn radially outwardly from the center of said image and for each of a second group of regions which are formed by dividing said image with a second group of lines which are imaginarily drawn radially outwardly from the center of said image, said second group of lines being interposed between said first group;

and said means (d) comprises means for comparing the results of said accumulations of adjacent regions of said first group and comparing the results of said accumulations of adjacent regions of said second group.

11. An apparatus as set forth in claim 8, further comprising:

(f) means for reading the signals of said picture elements in the order in which the corresponding segments are traversed by substantially spiral line which is imaginarily drawn on said image; and

(g) means for detecting a defect in said object in accordance with the mutual relationship between the signal of one of the picture elements and the signal of another picture element read out a little before the reading of the signal of said one of the picture elements.