Foreground object detection in a video surveillance system
First Claim
1. A computer-implemented method for detecting a foreground patch that depicts a foreground object in a sequence of video frames captured by a video camera, the method comprising:
- receiving a video frame in the sequence of video frame;
extracting a first foreground patch from the video frame to produce an extracted first foreground patch;
computing a motion flow field for the video frame that includes an angle and magnitude value corresponding to a feature in the video frame relative to the feature in a previous video frame;
filtering the motion flow field to produce a consistent motion flow field for the video frame that includes the extracted first foreground patch as a detected first foreground patch that includes the feature; and
tracking the first foreground object in the sequence of video frames based on the detected first foreground patch in order to follow the foreground object over time.
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Accused Products
Abstract
Techniques are disclosed for detecting foreground objects in a scene captured by a surveillance system and tracking the detected foreground objects from frame to frame in real time. A motion flow field is used to validate foreground objects(s) that are extracted from the background model of a scene. Spurious foreground objects are filtered before the detected foreground objects are provided to the tracking stage. The motion flow field is also used by the tracking stage to improve the performance of the tracking as needed for real time surveillance applications.
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Citations
20 Claims
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1. A computer-implemented method for detecting a foreground patch that depicts a foreground object in a sequence of video frames captured by a video camera, the method comprising:
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receiving a video frame in the sequence of video frame; extracting a first foreground patch from the video frame to produce an extracted first foreground patch; computing a motion flow field for the video frame that includes an angle and magnitude value corresponding to a feature in the video frame relative to the feature in a previous video frame; filtering the motion flow field to produce a consistent motion flow field for the video frame that includes the extracted first foreground patch as a detected first foreground patch that includes the feature; and tracking the first foreground object in the sequence of video frames based on the detected first foreground patch in order to follow the foreground object over time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A non-transitory computer-readable storage medium containing a program, which when executed on a processor, performs an operation for detecting a foreground patch that depicts a foreground object in a sequence of video frames captured by a video camera, the operation comprising:
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receiving a video frame in the sequence of video frame;
extracting a first foreground patch from the video frame to produce an extracted first foreground patch;
computing a motion flow field for the video frame that includes an angle and magnitude value for each pixel corresponding to a feature in the video frame relative to the feature in a previous video frame;filtering the motion flow field to produce a consistent motion flow field for the video frame that includes the extracted first foreground patch as a detected first foreground patch that includes the feature; and
tracking the first foreground object in the sequence of video frames based on the detected first foreground patch in order to follow the foreground object over time. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system, comprising:
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a video input source configured to provide a sequence of video frames; a processor; and
a memory containing a program, which, when executed on the processor is configured to perform an operation for detecting a foreground patch that depicts a foreground object in the sequence of video frames, the operation comprising;receiving a video frame in the sequence of video frame; extracting a first foreground patch from the video frame to produce an extracted first foreground patch; computing a motion flow field for the video frame that includes an angle and magnitude value for each pixel corresponding to a feature in the video frame relative to the feature in a previous video frame; filtering the motion flow field to produce a consistent motion flow field for the video frame that includes the extracted first foreground patch as a detected first foreground patch that includes the feature; and tracking the first foreground object in the sequence of video frames based on the detected first foreground patch in order to follow the foreground object over time. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification