Method of and apparatus for inspecting bottle or the like

• US 5,305,391 A
• Filed: 09/18/1991
• Issued: 04/19/1994
• Est. Priority Date: 10/31/1990
• Status: Expired due to Fees

• Current Assignee: TOYO Glass Company Limited (Toyo Seikan Group Holdings, Ltd.)
• Original Assignee: TOYO Glass Company Limited (Toyo Seikan Group Holdings, Ltd.)
• Inventors: Gomibuchi, Tadashi
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Prikockis, Larry J.
• Application Number:
  US07/761,524
• Time in Patent Office: 944 Days
• Field of Search: 382/8, 382/50, 250/223 B, 356/240, 209/526, 358/101, 358/106
• US Class Current: 382/142
• CPC Class Codes: G01N 2021/8887 based on image processing techniques
• 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 21/9045 Inspection of ornamented or stippled container walls
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: G06T 7/136 involving thresholding

Abstract

A method of and an apparatus for inspecting a bottle or the like by which the presence or absence of a defect, particularly a check, can be determined with a high degree of accuracy. Light is irradiated upon an inspection area of a rotating or moving object, and reflected light is photographed by a two-dimensional camera which includes solid-state image pickup elements. Picture element data for a first frame are fetched at a first point of time from the two-dimensional camera and stored into a memory, and then picture element data for a second frame are fetched at a second point of time after a fixed interval of time after the first point of time. Then, differences of the picture element data for the second frame from the picture element data for the first frame from the memory are taken and binary digitized with reference to predetermined brightness threshold level, and the differences which have one of two binary values are counted. The count number is compared with a predetermined number to determine the presence or absence of a defect in the object being inspected.

Claims

1. A method of inspecting a rotating or moving object for detecting a defect in the object, comprising the steps of irradiating light upon an inspection area of the object from an angle between a line extending perpendicular to a rotational axis of the object and the rotational axis of the object, photographing reflected light from the inspection area of the object by a two-dimensional camera, storing picture element data corresponding to a first frame at a first point of time of the photographed reflected light into a memory, storing picture element data corresponding to a second frame at a second point of time of the photographed reflected light after a fixed interval of time after the first point of time, said fixed interval of time being determined based on a predetermined period of time and a thinning out value that is determined based on a rotating speed of the object, calculating differences of the picture element data between the first and second frames, binary digitizing the differences with reference to a predetermined brightness threshold level, counting a number of the differences which have one of two binary values, and comparing the count number with a predetermined number to determine the presence or absence of a defect in the object.

2. A method as claimed in claim 1, wherein the brightness threshold level for binary digitization is adjusted in response to a speed of the object.

3. A method as claimed in claim 1, wherein a number of the differences which have one of two binary values is counted for each of a plurality of window areas included in a photographing area of said two-dimensional camera.

4. An apparatus for inspecting a rotating or moving object for detecting a defect in the object, comprising a light projector for irradiating light upon an inspection area of the object from an angle between a line extending perpendicular to a rotational axis of the object and the rotational axis of the object, a two-dimensional CCD camera for photographing reflected light from a fixed area of the object, a camera controller for successively fetching picture element data produced from said two-dimensional CCD camera for successive frames separated in time by a predetermined interval of time, said predetermined interval of time being determined based on a predetermined period of time and a thinning out value that is determine based on a rotating speed of the object, a memory for storing the fetched picture element data, a difference calculating circuit for calculating differences between the picture element data for different frames, a binary digitizing circuit for binary digitizing the calculated differences in accordance with a predetermined brightness threshold level, a counter for counting a number of the differences which have one of two binary values, and a main controller including means for adjusting the thinning out value and the predetermined brightness threshold level for said binary digitizing circuit in response to a speed signal representative of a speed of the rotating or moving object and means for counting a number of the differences which have one of two binary values, and means for comparing the count number with a predetermined number to determine the presence or absence of a defect in the object.

5. An apparatus as claimed in claim 4, wherein said main controller further comprises means for causing said counter to count a number of the differences which have one of two binary values for at least one of a plurality of window areas included in a photographing area of said two-dimensional CCD camera.

6. An apparatus as claimed in claim 4, further comprising a monitoring display apparatus for reproducing and displaying thereon data for a frame fetched by said camera controller.