Method and apparatus for configuring and testing a machine vision detector

• US 8,891,852 B2
• Filed: 11/02/2004
• Issued: 11/18/2014
• 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: Eames, Andrew, Mirtich, Brian V., Silver, William M
• Primary Examiner(s): Rahmjoo, Mike
• Application Number:
  US10/979,572
• Publication Number:
  US 20050276459A1
• Time in Patent Office: 3,668 Days
• Field of Search: 382/141, 382/144, 382/145, 382/159, 382/184
• 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 being manufactured in a production environment 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 being manufactured in the production environment;

displaying a portion of the sequence of images on a graphical user interface, the portion displayed chosen responsive to scrolling commands, the scrolling commands advancing the portion forward and backward in the sequence of images;

choosing, during a training phase, a first training image from the displayed portion of the sequence of images of a training object, the first training image being selected depending upon particular features recognized on the training object during the training phase;

configuring the image analysis device by creating, using the first training image chosen during the training phase, at least one vision tool to inspect objects similar in appearance to the training object of the first training image, the at least one vision tool being represented by a graphical image on the graphical user interface; and

performing an image analysis operation on the first training image to detect a feature on the training object of the training image, by computing a logic value to determine whether the feature is located in the field of view for each of the plurality of images such that the feature is determined to be located in the field of view for at least one image of the plurality of images when the logic value for the feature located in the field of view for the at least one image is greater than a threshold value.

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 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. An apparatus comprising:

an image analysis device that captures images of a continuously moving sequence of objects being manufactured in a production environment 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 being manufactured in the production environment;

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

a selection means for choosing, during a training phase, a training image from the sequence of images of a training object, the first training image being selected depending upon particular features recognized on the training object during the training phase;

a configuring means for configuring the image analysis device, using the training image selected during the training phase, at least one vision tool to inspect objects similar in appearance to the training object of the first training image, the at least one vision tool being represented by a graphical image on the graphical user interface; and

wherein the image analysis device performs an image analysis operation on the first training image to detect a feature on the training object of the training image, by computing a logic value to determine whether the feature is located in the field of view for each of the plurality of images such that the feature is determined to be located in the field of view for at least one image of the plurality of images when the logic value for the feature located in the field of view for the at least one image is greater than a threshold value.

11. The apparatus of claim 10, further comprising a production line configured to provide the motion relative to the image analysis device of the sequence of objects.

12. The apparatus of claim 10, wherein the image analysis device comprises an imager of no more than about 40,000 pixels.

13. The apparatus of claim 10, wherein

the human-machine interface further comprises

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

thumbnail”

images, and

an image view window 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.

14. The apparatus of claim 13, 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 display.

15. A method for configuring an image analysis device to inspect objects comprising the steps of:

capturing a sequence of images of a field of view of the image analysis device, the sequence of images including a plurality of images of each of a plurality of objects, the plurality of objects continuously moving relative to the field of view;

displaying a portion of the sequence of images on a graphical user interface;

defining, during a training phase, a first training image based upon a selection of an image from the displayed portion of the sequence of images of a training object, the first training image being selected depending upon particular features recognized on the training object during the training phase;

configuring the image analysis device by creating, using the first training image chosen during the training phase, at least one vision tool to inspect objects similar in appearance to the training object of the first training image, the at least one vision tool comprising one or more of a locator, a contrast detector, a brightness detector, and an edge detector; and

performing an image analysis operation on the first training image to detect a feature on the training object of the training image, by computing a logic value to determine whether the feature is located in the field of view for each of the plurality of images such that the feature is determined to be located in the field of view for at least one image of the plurality of images when the logic value for the feature located in the field of view for the at least one image is greater than a threshold value.

16. The method of claim 15, 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 portion displayed is chosen responsive to scrolling commands from a human user, the scrolling commands advancing the portion forward and backward in the sequence of images;

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.

17. The method of claim 16, wherein the image view window includes a graphical display of the at least one vision tool.

18. The method of claim 16, 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 when needed for display in the image view window.

19. The method of claim 15, 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.

20. The method of claim 19, wherein the at least one second training image includes at least one image that is dissimilar in appearance to the objects to be inspected.

21. The method of claim 20, wherein the at least one image that is dissimilar in appearance comprises an image where no object is present in the field of view.

22. The method of claim 20, 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.

23. The method of claim 15, 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.

24. The method of claim 15 wherein the portion displayed is chosen responsive to scrolling commands from the human user, the scrolling commands advancing the portion forward and backward in the sequence of images.

25. An apparatus comprising:

an image analysis device that captures images of a continuously moving 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;

an image view window for enabling selection of a training image during a training phase from the sequence of images of a training object, the first training image being selected depending upon particular features recognized on the training object during the training phase;

at least one vision tool created, using the first training image, to inspect objects similar in appearance to the training object of the first training image, and to configure the image analysis device, the at least one vision tool comprising one or more of a locator, a contrast detector, a brightness detector, and an edge detector; and

wherein the image analysis device performs an image analysis operation on the first training image to detect a feature on the training object of the training image, by computing a logic value to determine whether the feature is located in the field of view for each of the plurality of images such that the feature is determined to be located in the field of view for at least one image of the plurality of images when the logic value for the feature located in the field of view for the at least one image is greater than a threshold value.

26. The apparatus of claim 25, further comprising a production line configured to provide the motion relative to the image analysis device of the sequence of objects.

27. The apparatus of claim 25, wherein the image analysis device comprises an imager of no more than about 40,000 pixels.

28. The apparatus of claim 25, wherein

the human-machine interface further comprises

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

thumbnail”

images, and

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

scrolling controls responsive to the human user interacting with the graphical user interface.

29. The apparatus of claim 28, 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.