System for configuring an optoelectronic sensor

• US 8,422,729 B2
• Filed: 06/27/2007
• Issued: 04/16/2013
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: Cognex Corporation
• Original Assignee: Cognex Corporation
• Inventors: Silver, William M., Tremblay, Robert J., Eames, Andrew
• Primary Examiner(s): Rahmjoo, Mike
• Application Number:
  US11/769,494
• Publication Number:
  US 20080036873A1
• Time in Patent Office: 2,120 Days
• Field of Search: 382/100, 382/141, 382/151, 382/152, 382/191, 382/232, 709/246, 709/203, 709/208, 709/229, 709/232
• US Class Current: 382/100
• CPC Class Codes: G01N 2021/8909 Scan signal processing specially adapted for inspection of running sheets
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06V 10/443 by matching or filtering

Abstract

Disclosed are methods and apparatus for automatic optoelectronic detection and inspection of objects, based on capturing digital images of a two-dimensional field of view in which an object to be detected or inspected may be located, analyzing the images, and making and reporting decisions on the status of the object. Decisions are based on evidence obtained from a plurality of images for which the object is located in the field of view, generally corresponding to a plurality of viewing perspectives. Evidence that an object is located in the field of view is used for detection, and evidence that the object satisfies appropriate inspection criteria is used for inspection. Methods and apparatus are disclosed for capturing and analyzing images at high speed so that multiple viewing perspectives can be obtained for objects in continuous motion.

Claims

1. A system for configuring an optoelectronic sensor having a field of view, comprising:

a digital electronic memory, having a plurality of software elements stored therein, wherein each software element performs an action;

a plurality of connections, wherein each connection specifies that the action of a software element of the plurality of software elements depends on the action of at least one other software element of the plurality of software elements;

a first software element whose action analyzes a region of interest within the field of view so as to produce a measure of evidence for a visible condition in the field of view, the first software element being one of the plurality of software elements;

a second software element whose action makes a logic decision depending on the measure of evidence, the second software element being another of the plurality of software elements;

a third software element whose action controls an output signal depending on the logic decision, the third software element being yet another of the plurality of software elements;

a first connection that specifies that the second software element depends on the first software element, the first connection being one of the plurality of connections;

a second connection that specifies that the third software element depends on the second software element, the second connection being another of the plurality of connections; and

a human-machine interface comprising a display that shows using a ladder diagram of at least one of the plurality of software elements and at least one of the plurality of connections, the ladder diagram having rungs, wherein parts of a rung have at least one open contact representing the measure of evidence, and at least one icon representing the logic decision, wherein the open contact representing the measure of evidence precedes the icon representing the logic decision.

2. The system of claim 1, wherein the human-machine interface further comprises means to manipulate and edit the ladder diagram so as to modify the plurality of connections.

3. The system of claim 1, wherein

the display further shows using an alternative representation at least one of the plurality of software elements and at least one of the plurality of connections;

and

the human-machine interface further comprises means to switch between the ladder diagram and the alternative representation.

4. The system of claim 3, wherein the alternative representation is a wiring diagram.

5. The system of any one of claims 1-4, wherein the optoelectronic vision detector.

6. The system of claim 1 wherein, at least one rung comprises an open contact for the first software element that outputs the measure of evidence for a visible feature in the region of interest.

7. The system of claim 1, wherein the parts of the complete analysis may comprise two or more of:

inputs, measurements, logic decisions, and outputs.

8. Method for configuring an optoelectronic sensor and representing the resulting optoelectronic program, the method comprising:

providing a plurality of software elements stored on a digital memory;

selecting, by a processor, a first software element to be applied on a portion of an image for measuring evidence in the portion of the image, the first software element being one of the plurality of software elements;

selecting, by the processor, a second software element that employs a logic decision for analyze the evidence, the second software element being one of the plurality of software elements; and

generating instructions, by the processor, for displaying a ladder diagram on a HMI display, the ladder diagram having rungs, the rungs having at least one open contact representing the evidence, and at least one icon representing the logic decision, wherein the open contact representing the measure of evidence precedes the icon representing the logic decision, wherein parts of a rung represent portions of the optoelectronic program.

9. The method of claim 8, further comprising:

selecting, by the processor, a third software element that produces output based on the logic decision, the third software element being one of the plurality of software elements; and

displaying on the ladder diagram the third software element having as input one of the evidence and the logic decision from at least one other of the plurality of software elements.

10. The method of claim 9, wherein the optoelectronic sensor is a vision detector.

11. The method of claim 8, further comprising

providing, by the processor, a graphical tool on the HMI display for manipulating and editing the ladder diagram so as to modify one of the inputs and outputs to direct to a different one of the plurality of software elements.

12. The method of claim 8, further comprising:

providing, by the processor, an alternative representation at least one of the plurality of software elements and at least one of the plurality of connections; and

providing a means based on the HMI to switch between the ladder diagram and the alternative representation.

13. The method of claim 12, wherein providing the alternative representation comprises:

providing, by the processor, a wiring diagram to represent the at least one of the plurality of software elements and the at least one of the plurality of connections.

14. The method of claim 8, wherein the optoelectronic sensor is a vision detector.

15. The method of claim 8, wherein the parts of the optoelectronic program may comprise two or more of:

inputs, measurements, logic decisions, and outputs.

16. A computer program product for graphically representing an optoelectronic program, the product tangibly embodied in a non-transitory computer readable medium, the computer program product comprising instructions being operable to cause a data processing apparatus to:

generate instructions for display of a ladder diagram of the optoelectronic program, the program comprising;

calculating a measure of evidence for a visible condition of a portion of a received image, and

computing a logic decision about a potential object in the received image based on the measure of evidence; and

the ladder diagram comprising one or more rungs, and having at least one open contact representing the measure of evidence, and at least one icon representing the logic decision about the potential object, wherein the open contact representing the measure of evidence precedes the icon representing the logic decision and wherein parts of a rung represent parts of the optoelectronic program.

17. The medium of claim 16, wherein the parts of the optoelectronic program may comprise two or more of:

inputs, measurements, logic decisions, and outputs.

18. The medium of claim 16, further comprising instructions for configuring and representing the optoelectronic program, wherein the program is configured by a user using an HMI interface.

19. The medium of claim 16, further comprising instructions wherein the user can edit the ladder diagram without changing the configuration of the program.

20. The medium of claim 16, further comprising instructions wherein the user can hide any contacts of the optoelectronic program on the ladder.

21. The medium of claim 16, further comprising instructions wherein computing a logic decision about a potential object in the received image based on the measure of evidence comprise computing presence of absence of the potential object in the received image.