Method and apparatus for automatic visual detection, recording, and retrieval of events

• US 20050276461A1
• Filed: 05/26/2005
• 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: Phillips, Brian S., Silver, William M.
• Granted Patent: US 8,243,986 B2
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51

Abstract

Disclosed are methods and apparatus for automatic visual detection of events, for recording images of those events and retrieving them for display and human or automated analysis, and for sending synchronized signals to external equipment when events are detected. An event corresponds to a specific condition, among some time-varying conditions within the field of view of an imaging device, that can be detected by visual means based on capturing and analyzing digital images of a two-dimensional field of view in which the event may occur. Events may correspond to rare, short duration mechanical failures for which obtaining images for analysis is desirable. Events are detected by considering evidence obtained from an analysis of multiple images of the field of view, during which time moving mechanical components can be seen from multiple viewing perspectives.

Claims

1-16. -16. (canceled)

17. A method for detection and reporting of a plurality of events, comprising:

determining, for each event of the plurality of events, a corresponding mark time that is a function of a time at which the event occurs, wherein

determining the corresponding mark time occurs at a corresponding decision point that differs from the corresponding mark time by a corresponding decision delay; and

the decision delays corresponding to the plurality of events are variable;

producing, for each event of the plurality of events, a corresponding signal at a corresponding report time that follows the corresponding mark time by a delay interval; and

using, for each event of the plurality of events, the corresponding report time of the corresponding signal to indicate the corresponding mark time.

18. The method of claim 17, wherein each mark time is proportional to a time at which the corresponding event occurs.

19. The method of claim 17, wherein each mark time is an encoder count that is a function of a time at which the corresponding event occurs.

20. The method of claim 17, wherein each event of the plurality of events comprises a flow event, the flow event comprising motion of an object across a mark point, the corresponding mark time responsive to a time at which the object crosses the mark point.

21. The method of claim 17, wherein each event of the plurality of events comprises a stroke event, the stroke event comprising motion of an object advancing to and retreating from an apex, the corresponding mark time responsive to a time at which the object reaches the apex.

22. The method of claim 17, further comprising

selecting an event type from a plurality of event types;

and

wherein determining the corresponding mark time is responsive to the event type.

23. The method of claim 22, wherein the plurality of event types comprises a flow event type and a stroke event type.

24. The method of claim 22, wherein selecting the event type is responsive to a human-machine interface.

25. The method of claim 17, wherein the delay interval is selected responsive to a human-machine interface.

26. The method of claim 17, further comprising using a first-in first-out buffer to hold information needed for producing each corresponding signal at each corresponding report time.

27. A system for detection and reporting of a plurality of events, comprising:

an analysis process that determines, for each event of the plurality of events, a corresponding mark time that is a function of a time at which the event occurs, wherein

the analysis process determines the corresponding mark time at a corresponding decision point that differs from the corresponding mark time by a corresponding decision delay; and

the decision delays corresponding to the plurality of events are variable; and

an output process that produces, for each event of the plurality of events, a corresponding signal at a corresponding report time that follows the corresponding mark time by a delay interval.

28. The system of claim 27, wherein each mark time is proportional to a time at which the corresponding event occurs.

29. The system of claim 27, wherein each mark time is an encoder count that is a function of a time at which the corresponding event occurs.

30. The system of claim 27, wherein each event of the plurality of events comprises a flow event, the flow event comprising motion of an object across a mark point, the corresponding mark time responsive to a time at which the object crosses the mark point.

31. The system of claim 27, wherein each event of the plurality of events comprises a stroke event, the stroke event comprising motion of an object advancing to and retreating from an apex, the corresponding mark time responsive to a time at which the object reaches the apex.

32. The system of claim 27, further comprising

a selection process that selects an event type from a plurality of event types;

and

wherein the analysis process determines the corresponding mark time using the event type.

33. The system of claim 32, wherein the plurality of event types comprises a flow event type and a stroke event type.

34. The system of claim 32, further comprising a human-machine interface that is used to select the event type.

35. The system of claim 27, further comprising a human-machine interface that is used to select the delay interval.

36. The system of claim 27, further comprising a first-in first-out buffer that holds information needed for producing each corresponding signal at each corresponding report time.