Apparatus and method for automated visual inspection of objects

• US 6,061,086 A
• Filed: 09/11/1997
• Issued: 05/09/2000
• Est. Priority Date: 09/11/1997
• Status: Expired due to Term

• Current Assignee: Nordischer Maschinenbau Rud. Baader GmbH + Co. KG
• Original Assignee: Canopular East Incorporated
• Inventors: Reimer, Ernest M., Hearn, Paul, Hermanto, Ivi
• Primary Examiner(s): Le, Vu
• Application Number:
  US08/927,332
• Time in Patent Office: 971 Days
• Field of Search: 382/148, 382/143, 382/149, 382/141, 348/86, 348/87, 348/88, 348/89, 348/92, 348/94, 348/95, 348/125, 348/128, 348/203, 348/204, 348/205, 348/206, 426/231
• US Class Current: 348/125
• 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

Abstract

The present invention relates to an apparatus and method for the automated inspection of objects for the presence of visual anomalies. The apparatus includes a first wide angle camera for acquiring an image of the object, a processor for detecting targets and generating target location from the image of the object, a two axis post-objective scanner associated with a high resolution camera for directing target image to the high resolution camera. The scanner provides a mechanism for saccadic emulation in combination with a high resolution video camera, which can be synchronized to the frame rate of the video camera for rapid high resolution examination of an object. The method according to the present invention comprises the steps of: capturing an image of at least a portion of an object; identifying visual anomalies as targets and detecting any targets on the object; generating location data for a detected target; emulating saccadic movement to selectively capture a high resolution image of a target; and generating an output for analysis. The apparatus and method are particularly suited for the automated detection of defects, in particular parasites, in fish fillets. It is an advantage of the present invention that post-objective scanning permits the camera to remain stationary, while only the mirrors are moved, to acquire high resolution data of substantially only the targets, resulting in increased speed and reduced processing time.

Claims

1. An apparatus for the inspection of objects in an inspection field for the presence of a target comprising:

a light source;

first and second optic sensor means each directed towards said object for concurrent viewing of said object;

first processor means associated with said first optic sensor for detecting a target and for generating location data for a target;

said second optic sensor means for selectively acquiring high resolution image data of a located target;

positioning means for saccadic emulation associated with the second optic sensor means for directing the image data from a target location to the sensor whereby said high resolution target image data is acquired and processed generally immediately following said generation of target location data by said optic sensor and said first processor means; and

second processor means associated with said second optic sensor for generating an output from the target image data for analysis.

2. An apparatus for the inspection of objects as defined in claim 1, wherein the positioning means associated with the optic sensor means comprises a post-objective scanner.

3. An apparatus for the inspection of objects as defined in claim 2, wherein the post-objective scanner is selectively directable in two axes toward a location on a plane in the inspection field.

4. An apparatus for the inspection of objects as defined in claim 3, wherein the post-objective scanner is directable sequentially towards each target location.

5. Apparatus for the inspection of objects as defined in claim 4, wherein the post-objective scanner has a random access of less than 33 milliseconds.

6. Apparatus for the inspection of objects as defined in claim 5, wherein the scanner has a random access of about 3 milliseconds.

7. An apparatus for the inspection of objects as defined in claim 1, wherein a wide angle optic sensor means is provided to acquire image data of the object to provide to the first processor means for detecting any target and for generating location data for each target.

8. An apparatus for the inspection of objects as defined in claim 7, wherein the wide angle optic sensor means captures low resolution image data of the object, and the optic sensor means comprises a high resolution optic sensor means having a smaller field of view than that of the wide angle sensor means.

9. An apparatus for the inspection of objects as defined in claim 7, wherein the wide angle sensor means and the high resolution sensor means are charge coupled device video cameras.

10. An apparatus for the inspection of objects as defined in claim 7, wherein targets comprise visual anomalies.

11. An apparatus for the inspection of objects as defined in claim 10, wherein the first processor means includes a blob analysis routine for detecting visual anomalies.

12. Apparatus for the inspection of objects as defined in claim 7, wherein the wide angle optic sensor means and the high resolution optic sensor means comprise the same apparatus operating in different modes.

13. Apparatus for the inspection of objects as defined in claim 7, wherein the field of view of the high resolution optic sensor means is variable in response to the target size.

14. An apparatus for the inspection of objects as defined in claim 1, wherein the high resolution image includes a target substantially in the absence of unnecessary data.

15. Use of the apparatus for the inspection of objects as defined in claim 1 for the detection of defects including parasites in fish fillets.

16. A method for the inspection of objects for the presence of targets comprising the steps of:

providing an apparatus as defined in claim 1;

detecting any targets on the object with said first optic sensor means;

generating location data for a detected target;

emulating saccadic movement to selectively capture a high resolution image of a target with said second sensor means generally immediately following said step of generating location data and without moving said object; and

generating an output for analysis.

17. A method for the inspection of objects as defined in claim 16, wherein saccadic movement emulation is synchronized to sequentially capture a high resolution image of each target detected at the frame rate of a video imaging means.

18. A method as defined in claim 16, wherein the method includes a first step of treating an object with a marker prior to inspection to identify any targets and a detection means is provided for cooperation with the selected marker for detecting the presence of a target.

19. A method for the inspection of objects as defined in claim 16, wherein the method includes a first step of capturing a first image of at least a portion of an object from which any targets can be detected.

20. A method for the inspection of objects as defined in claim 19, including identifying visual anomalies as targets for detection.

21. A method as defined in claim 16, wherein said object comprises a fish fillet, and said targets include parasites, said step of generating an output for analysis includes the step of processing target image data to determine whether said target is a defect or a parasite and identifying a filet as having a defect or parasite.

22. In an apparatus for the inspection of objects for the presence of targets including an optic sensor, the improvement comprising:

positioning means for saccadic emulation associated with the optic sensor for directing image data of a target to the sensor including a post-objective scanner.

23. An apparatus for the inspection of objects as defined in claim 22, wherein the post-objective scanner is selectively directable in two axes toward any location on a plane in an inspection field.

24. Apparatus for the inspection of objects as defined in claim 23, wherein the post-objective scanner has a random access of less than 33 milliseconds.

25. Apparatus for the inspection of objects as defined in claim 24, wherein the scanner has a random access of about 3 milliseconds.

26. Apparatus for the inspection of objects as defined in claim 24, wherein the optic sensor comprises a charge coupled device video camera and the scanner has a random access rate which can be synchronized with the frame rate of the camera.

27. Apparatus for the inspection of objects as defined in claim 22, further including a processor means including a blob analysis routine.

28. An apparatus for the inspection of objects for visual targets comprising:

a light source;

a first video imaging means for acquiring a visual image having a field of view including at least a portion of an object and for transmitting image data to a central processor;

a second video imaging means for viewing said object concurrently with said first video imaging means for acquiring a second visual image having a field of view smaller than the field of view of the first video imaging means and for transmitting image data to a central processor immediately following transmission of data from said first video imaging means;

a central processor for receiving image data from the first and second video imaging means and for generating an output for analysis including;

a frame grabber for converting the image data of first and second video imaging means to digital data and isolating a single image;

a digital signal processor assembly programmed for morphological manipulation of the image data from the first video imaging means to detect individual visual anomalies as targets and for generating location coordinates for each target; and

a post-objective scanner associated with the second video imaging means including;

a mirror directable in two axes for selectively directing image data from a specified target location to the second video imaging means, and

a driver for accessing location coordinates and directing the mirror towards a target location.

29. Apparatus for the inspection of objects as defined in claim 28, wherein the video imaging means comprise charge coupled device video cameras and the scanner has a random access rate which can be synchronized with the frame rate of the camera.

30. An automated station for the detection of defects including parasites in fish fillets including:

a viewing head comprising;

first image recording means for viewing said object concurrently with said first image recording means and for acquiring image data of an object in an inspection field;

second image recording means having a smaller field of view than that of the first image recording means for selectively acquiring higher resolution image data;

positioning means associated with the second image recording means, for directing image data of substantially only a target to the second image recording means including a post-objective scanner directable in two axes toward any location on a plane in the inspection field;

a candling table for back-lighting a fillet;

a light source for providing illumination of the inspection field;

advancing means for presenting a fillet on the candling table to the first and second cameras;

a support for supporting the viewing head a distance from the candling table;

first processor means for processing the image data of the object to isolate any targets, and for generating location data for each target;

second processor means for generating an output from the target image data for analysis; and

wherein said first and second image recording means, and said first and second processor means operate generally one immediately following the other to emulate the functioning of a human eye to generally nearly simultaneously or in rapid succession identify targets within a broad field of view and resolve such targets within a narrow field of view at higher resolution.