Method and apparatus for automatic visual event detection
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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.
126 Citations
48 Claims
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1-16. -16. (canceled)
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17. A method for automatic visual detection and reporting of an event, comprising:
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capturing a plurality of frames, each frame in the plurality of frames comprising an image of a two-dimensional field of view in which the event occurs, the event comprising a motion of an object along a path, the path having a mark point, the event further comprising a mark time at which the object is located at the mark point;
choosing, responsive to a first analysis of the plurality of frames, a plurality of event frames from the plurality of frames, such that the first analysis indicates sufficient evidence that the object is located along the path for each frame of the plurality of event frames;
obtaining a plurality of capture times corresponding to the plurality of event frames, each capture time of the plurality of capture times being a function of a time at which the corresponding event frame was captured;
computing, responsive to a second analysis of the plurality of event frames, a plurality of location values, each location value of the plurality of location values responsive to a position of the object along the path in an associated event frame as computed by the second analysis;
determining the mark time using the plurality of location values and the plurality of capture times; and
producing a signal at a report time that follows the mark time by a delay interval. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A system for automatic visual detection and reporting of an event, comprising:
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a capture process that captures a plurality of frames, each frame in the plurality of frames comprising an image of a two-dimensional field of view in which the event occurs, the event comprising a motion of an object along a path, the path having a mark point, the event further comprising a mark time at which the object is located at the mark point;
a first selection process that chooses a plurality of event frames from the plurality of frames, such that the first selection process judges that there is sufficient evidence that the object is located along the path for each frame of the plurality of event frames;
a timing process that obtains a plurality of capture times corresponding to the plurality of event frames, each capture time of the plurality of capture times being a function of a time at which the corresponding event frame was captured;
a first analysis process that computes a plurality of location values, each location value of the plurality of location values responsive to a position of the object along the path in an associated event frame;
a second analysis process that determines the mark time using the plurality of location values and the plurality of capture times; and
an output process that produces a signal at a report time that follows the mark time by a delay interval. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification