Method and apparatus for configuring and testing a machine vision detector

• US 20050276459A1
• Filed: 11/02/2004
• Published: 12/15/2005
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Original Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Inventors: Silver, William M., Eames, Andrew, Mirtich, Brian V.
• Granted Patent: US 8,891,852 B2
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G06F 3/04817 using icons graphical or visual programming using iconic symbols G06F8/34
• CPC Class Codes: G06F 3/0485 Scrolling or panning
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06V 20/00 Scenes; Scene-specific elements control of digital cameras H04N23/60

Abstract

Disclosed are systems and methods for configuring a vision detector, wherein a training image is obtained from a production line operating in continuous motion so as to provide conditions substantially identical to those that will apply during actual manufacturing and inspection of objects. A training image can be obtained without any need for a trigger signal, whether or not the vision detector might use such a signal for inspecting the objects. Further disclosed are systems and methods for testing a vision detector by selecting, storing, and displaying a limited number of images from a production run, where those images correspond to objects likely to represent incorrect decisions.

Claims

1. A method for configuring an image analysis device to inspect objects comprising:

continuously moving a sequence of objects relative to a field of view of the image analysis device;

capturing a sequence of images of the field of view, such that the sequence of images includes a plurality of images of each of a plurality of objects from the sequence of objects;

displaying a portion of the sequence of images for viewing by a human user, the portion displayed chosen responsive to scrolling commands from the human user, the scrolling commands capable of advancing the portion forward and backward in the sequence of images;

choosing a first training image from the displayed portion of the sequence of images; and

configuring the image analysis device by creating, using the first training image, at least one vision tool capable of inspecting objects similar in appearance to the object of the first training image.

2. The method of claim 1, wherein

the displaying step further comprises

displaying the portion of the sequence of images as a succession of low-resolution “

thumbnail”

images in a filmstrip window of a graphical user interface, and

displaying at least one image of the portion of the sequence of images as a full-resolution image in an image view window;

the scrolling commands are responsive to the human user interacting with the graphical user interface; and

the at least one image of the portion of the sequence of images includes the first training image.

3. The method of claim 2, wherein the image view window includes a graphical display of the at least one vision tool.

4. The method of claim 2, wherein

the sequence of images are stored in a memory on the image analysis device;

the graphical user interface is running on a separate human-machine interface;

the low-resolution “

thumbnail”

images are derived from the stored sequence of images by the image analysis device and transmitted to the human-machine interface for display in the filmstrip window; and

the full-resolution image is transmitted by the image analysis device to the human-machine interface only when needed for display in the image view window.

5. The method of claim 1, further comprising

choosing at least one second training image from the displayed portion of the sequence of images;

and

using the at least one second training image to perform at least of one of

creating additional vision tools to inspect objects,

adjusting a position of a region of a previously created vision tool,

adjusting a size of a region of a previously created vision tool,

adjusting an orientation of a region of a previously created vision tool,

adjusting an operating parameter of a previously created vision tool, and

assessing the operation of a previously created vision tool.

6. The method of claim 5, wherein the at least one second training image includes at least one image that is dissimilar in appearance to the objects to be inspected.

7. The method of claim 6, wherein the at least one image that is dissimilar in appearance comprises an image where no object is present in the field of view.

8. The method of claim 6, wherein the at least one image that is dissimilar in appearance comprises an image where an object is partially present in the field of view.

9. The method of claim 1, wherein the image analysis device is a vision detector capable of inspecting an object by analyzing a plurality of images of the object, the plurality of images comprising a plurality of positions of the object in the field of view of the vision detector.

10. A method for testing a vision detector comprising:

continuously moving a sequence of objects relative to a field of view of the vision detector;

capturing a plurality of groups of frames, each frame of the plurality of groups of frames comprising an image of the field of view, such that each group of frames of the plurality of groups of frames comprises a plurality of images of one corresponding object in the sequence of objects;

analyzing each object to determine a plurality of results corresponding to the plurality of groups of frames, each result in the plurality of results comprising information about the status of the object corresponding to the group of frames;

storing, responsive to the plurality of results, a selected set of groups of frames from the plurality of groups of frames, the set of groups of frames comprising a stored set of images; and

displaying a portion of the stored set of images for viewing by a human user, the portion displayed chosen responsive to scrolling commands from the human user, the scrolling commands capable of advancing the portion displayed forward and backward in the stored set of images.

11. The method of claim 10, wherein

the displaying step further comprises

displaying the portion of the stored set of images as a succession of low-resolution “

thumbnail”

images in a filmstrip window of a graphical user interface, and

displaying at least one image of the portion of the stored set of images as a full-resolution image in an image view window; and

the scrolling commands are responsive to the human user interacting with the graphical user interface.

12. The method of claim 11, wherein

the stored set of images are stored in a memory on the vision detector;

the graphical user interface is running on a separate human-machine interface;

the low-resolution “

thumbnail”

images are derived from the stored set of images by the vision detector and transmitted to the human-machine interface for display in the filmstrip window; and

the full-resolution image is transmitted by the vision detector to the human-machine interface only when needed for display in the image window.

13. The method of claim 10, wherein

each result in the plurality of results indicates whether the corresponding object passes inspection;

and

the selected set of groups of frames corresponds to objects for which the corresponding results indicate that the objects pass inspection.

14. The method of claim 10, wherein

each result in the plurality of results indicates whether the corresponding object passes inspection;

and

the selected set of groups of frames corresponds to objects for which the corresponding results indicate that the objects do not pass inspection.

15. The method of claim 10, wherein

each result in the plurality of results comprises a number that indicates a relative confidence that the corresponding object passes inspection;

the number is compared to a decision threshold to decide whether the corresponding object passes inspection; and

the selected set of groups of frames corresponds to objects for which the corresponding numbers are close to the decision threshold.

16. The method of claim 10, wherein

each result in the plurality of results comprises a number that indicates a relative confidence that the corresponding object was detected;

the number is compared to a decision threshold to decide whether the corresponding object was detected; and

the selected set of groups of frames corresponds to objects for which the corresponding numbers are close to the decision threshold.

17. An apparatus comprising:

an image analysis device configured to capture images of a sequence of objects to provide a sequence of images, the sequence of objects having a motion relative to the image analysis device, the image analysis device having a frame rate such that the sequence of images includes a plurality of images of each of a plurality of objects from the sequence of objects;

a human-machine interface configured to display a portion of the sequence of images;

a selection means for choosing a training image from the sequence of images; and

a configuring means for configuring the image analysis device using the training image.

18. The apparatus of claim 17, further comprising a production line configured to provide the motion relative to the image analysis device of the sequence of objects.

19. The apparatus of claim 17, wherein the image analysis device comprises an imager of no more than about 40,000 pixels.

20. The apparatus of claim 17, wherein

the human-machine interface further comprises

a filmstrip window of a graphical user interface capable of displaying the portion of the sequence of images as a succession of low-resolution “

thumbnail”

images, and

an image view window capable of displaying at least one image of the portion of the sequence of images as a full-resolution image; and

the selection means further comprises scrolling controls responsive to the human user interacting with the graphical user interface.

21. The apparatus of claim 20, wherein

the image analysis device is further configured to derive the low-resolution “

thumbnail”

images from the stored sequence of images;

the human-machine interface runs the graphical user interface; and

the apparatus further comprising

a memory on the image analysis device configured to store the sequence of images, and

a communications interface configured to transmit the low-resolution “

thumbnail”

images from the image analysis device to the human-machine interface for display in the filmstrip window, and to transmit the full-resolution image to the human-machine interface only when needed for display in the image view window.

22. An apparatus comprising:

a sequence of objects;

a vision detector having a field of view, the sequence of objects in continuous motion relative to the field of view, the vision detector configured to

capture a plurality of groups of frames, each frame of the plurality of groups of frames comprising an image of the field of view, such that each group of frames of the plurality of groups of frames comprises a plurality of images of one corresponding object in the sequence of objects,

analyze each object to determine a plurality of results corresponding to the plurality of groups of frames, each result in the plurality of results comprising information about the status of the object corresponding to the group of frames;

a memory configured to store, responsive to the plurality of results, a selected set of groups of frames from the plurality of groups of frames, the set of groups of frames comprising a stored set of images; and

a human-machine interface configured to display a portion of the stored set of images for viewing by a human user, the portion displayed chosen responsive to scrolling commands from the human user, the scrolling commands capable of advancing the portion displayed forward and backward in the stored set of images.

23. The apparatus of claim 22, wherein

the human-machine interface further comprises

a filmstrip window of a graphical user interface configured to display the portion of the stored set of images as a succession of low-resolution “

thumbnail”

images, and

an image view window configured to display at least one image of the portion of the stored set of images as a full-resolution image in; and

the scrolling commands are responsive to the human user interacting with the graphical user interface.

24. The apparatus of claim 23, wherein

the image analysis device is further configured to derive the low-resolution “

thumbnail”

images from the stored set of images;

the human-machine interface runs the graphical user interface; and

the apparatus further comprising

a memory on the image analysis device configured to store the stored set of images, and

a communications interface configured to transmit the low-resolution “

thumbnail”

images from the image analysis device to the human-machine interface for display in the filmstrip window, and to transmit the full-resolution image to the human-machine interface only when needed for display in the image view window.

25. The apparatus of claim 22, wherein

each result in the plurality of results indicates whether the corresponding object passes inspection;

and

the selected set of groups of frames corresponds to objects for which the corresponding results indicate that the objects pass inspection.

26. The apparatus of claim 22, wherein

each result in the plurality of results indicates whether the corresponding object passes inspection;

and

the selected set of groups of frames corresponds to objects for which the corresponding results indicate that the objects do not pass inspection.

27. The apparatus of claim 22, wherein

each result in the plurality of results comprises a number that indicates a relative confidence that the corresponding object passes inspection;

the number is compared to a decision threshold to decide whether the corresponding object passes inspection; and

the selected set of groups of frames corresponds to objects for which the corresponding numbers are close to the decision threshold.

28. The apparatus of claim 22, wherein

each result in the plurality of results comprises a number that indicates a relative confidence that the corresponding object was detected;

the number is compared to a decision threshold to decide whether the corresponding object was detected; and

the selected set of groups of frames corresponds to objects for which the corresponding numbers are close to the decision threshold.