Distributed vision system with multi-phase synchronization

• US 9,325,894 B2
• Filed: 04/15/2014
• Issued: 04/26/2016
• Est. Priority Date: 12/29/2009
• Status: Active Grant

• Current Assignee: Cognex Corporation
• Original Assignee: Cognex Corporation
• Inventors: McClellan, James R.
• Primary Examiner(s): Flohre, Jason
• Assistant Examiner(s): TEJANO, DWIGHT ALEX C
• Application Number:
  US14/252,825
• Publication Number:
  US 20150049212A1
• Time in Patent Office: 742 Days
• Field of Search: 348/211.3
• US Class Current: 1/1
• CPC Class Codes: H04N 21/242 Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• CPC Class Codes: H04N 21/4302 Content synchronisation processes, e.g. decoder synchronisation
• CPC Class Codes: H04N 23/662 by using master/slave camera arrangements for affecting the control of camera image capture, e.g. placing the camera in a desirable condition to capture a desired image
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums

Abstract

This invention provides a system and method for synchronization of vision system inspection results produced by each of a plurality of processors that includes a first bank (that can be a “master” bank) containing a master vision system processor and at least one slave vision system processor. At least a second bank (that can be one of a plurality of “slave” banks) contains a master vision system processor and at least one slave vision system processor. Each vision system processor in each bank generates results from an image acquired and processed in a given inspection cycle. The inspection cycle can be based on an external trigger or other trigger signal, and it can enable some or all of the processors/banks to acquire and process images at a given time/cycle. In a given cycle. each of the multiple banks can be positioned to acquire an image of a respective region of a plurality of succeeding regions on a moving line. A synchronization process (a) generates a unique identifier and that passes a trigger signal with the unique identifier associated with the master processor in the first bank to each of the slave processor in the master bank and each of the master and slave processor and (b) receives consolidated results via the master processor of the second bank, having the unique identifier and consolidated results from the results from the first bank. The process then (c) consolidates the results for transmission to a destination if the results are complete and the unique identifier of each of the results is the same.

Claims

1. A method for synchronizing results of a plurality of vision system processors, that processes acquired images, to generate results therefrom, comprising the steps of:

providing a master processor with a discrete master synchronization process associated therewith;

providing a slave camera bank interconnected to the discrete master processor and including at least one (a) master vision system processor and at least one (b) slave vision system processor interconnected thereto;

providing a master camera bank interconnected to the discrete master processor and including at least one (c) master vision system processor and at least one (d) slave vision system processor interconnected thereto;

in each inspection cycle, receiving, by each of the (a) master vision system processor, (b) slave vision system processor, (c) master vision system processor, and (d) slave vision system processor, a trigger signal, and in response thereto, acquiring and processing an image, the trigger signal including a unique inspection cycle identifier;

after acquiring and processing images with each of the (a) master vision system processor, (b) slave vision system processor, consolidating the results of the (a) master vision system processor, (b) slave vision system processor in the master bank and transmitting consolidated slave bank results to the master processor by a first communication link, the consolidated slave bank results including the unique inspection cycle identifier;

after acquiring and processing images with each of the (c) master vision system processor, and (d) slave vision system processor, consolidating the results of the (c) master vision system processor, and (d) slave vision system processor in the slave bank and transmitting consolidated master bank results to the master processor by a second communication link, the consolidated master bank results including the unique inspection cycle identifier;

with the master synchronization process associated with the discrete master processor, determining if the consolidated master bank results and the consolidated slave bank results are complete and that each of the inspection cycle identifiers is the same, and if the results are complete and the same, transmitting the complete results to a predetermined destination.

2. The method of claim 1, wherein the discrete master processor is discrete from the master bank and the slave bank.

3. The method of claim 1, further comprising:

providing at least a second slave camera bank interconnected to the discrete master processor and including at least one (e) master vision system processor and at least one (f) slave vision system processor interconnected thereto.

4. The method as set forth in claim 1 further comprising, if the synchronization process determines that at least one of (i) the results are not complete and (ii) each of the inspection cycle identifiers are not the same, indicating an error to a controller.

5. The method as set forth in claim 2 further comprising:

providing a common time reference to each of the (c) master vision system processor and the (d) slave vision system processor and appending a first timestamp to the consolidated master bank results based upon the common time reference; and

providing the common time reference to each of the (a) master vision system processor and the (b) slave vision system processor and appending a second timestamp to the consolidated slave bank results based upon the common time reference.

6. The method as set forth in claim 5 wherein the master synchronization process determines completeness of the consolidated master bank results and the consolidated slave bank results based upon known time sequence between each timestamp on each result.

7. The method as set forth in claim 1 wherein the trigger comprises an external trigger and wherein the method further comprises generating the external trigger from at least one of a group consisting of a presence detector that senses objects, an encoder that senses movement, and a motion control system with a positional reference.

8. The method as set forth in claim 1 further comprising performing an action with respect to the moving line based on the complete results at the predetermined destination.

9. The method as set forth in claim 1 further comprising a plurality of cameras each in association with the vision system processors that acquire images, wherein one or more of the cameras are either (a) positioned to view predetermined locations on a moving line, or (b) positioned by a motion control device to acquire images of predetermined locations.

10. The method as set forth in claim 1 further comprising:

providing a common positional reference to each of the (c) master vision system processor and the (d) slave vision system processor and appending a positional reference to the consolidated master bank results based upon the common positional reference;

providing the common positional reference to each of the (a) master vision system processor and the (b) slave vision system processor and appending a positional reference to the consolidated slave bank results based upon the common positional reference.

11. The method as set forth in claim 10 wherein the master synchronization process determines completeness of the consolidated master bank results and the consolidated slave bank results based upon a positional relationship between each positional reference on each result.

12. The method of claim 1, wherein the first communication link is discrete from the second communication link.