Method of tracking an object in a video stream
First Claim
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1. A method of tracking an object in a video stream comprising a plurality of video frames, the method comprising:
- (a) running an object detector, on a computer, at a plurality of sampling locations, the locations defining a first grid spaced across a first video frame, and recording a hit, to electronic storage, at each location where an object of interest is found; and
(b) running the object detector, on the computer, at a further plurality of sampling locations defining a second grid spaced across a succeeding second video frame, the second grid being offset from the first grid, wherein larger points, which have a size of at least 2×
2 points of a fine grained grid, cover the entire first grid and the entire second grid and wherein each of the larger points has one of the sampling locations of the first grid and one of the further sampling locations of the second grid and wherein each of the further sampling locations is offset with respect to a corresponding sampling location of the first grid for a respective larger point and simultaneously running the detector employing parallel processing, on the computer, in addition at one or more further locations on the second frame derived from each location on the first frame at which a hit was recorded.
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Abstract
A method of tracking an object such as a face in a video stream comprises running an object detector at a plurality of locations on a first frame, defining a coarse grid. This is repeated for second and subsequent frames, with the grid slightly offset each time so that, ultimately, all of the points on a fine grid are covered but in several passes. When an object such as a face is located on one frame, positional and/or scale information is propagated to the next frame to assist in the tracking of that object onto the next frame.
56 Citations
19 Claims
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1. A method of tracking an object in a video stream comprising a plurality of video frames, the method comprising:
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(a) running an object detector, on a computer, at a plurality of sampling locations, the locations defining a first grid spaced across a first video frame, and recording a hit, to electronic storage, at each location where an object of interest is found; and (b) running the object detector, on the computer, at a further plurality of sampling locations defining a second grid spaced across a succeeding second video frame, the second grid being offset from the first grid, wherein larger points, which have a size of at least 2×
2 points of a fine grained grid, cover the entire first grid and the entire second grid and wherein each of the larger points has one of the sampling locations of the first grid and one of the further sampling locations of the second grid and wherein each of the further sampling locations is offset with respect to a corresponding sampling location of the first grid for a respective larger point and simultaneously running the detector employing parallel processing, on the computer, in addition at one or more further locations on the second frame derived from each location on the first frame at which a hit was recorded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for tracking an object in a video stream comprising a plurality of video frames, the apparatus including an object detector comprising:
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a computer that is programmed for (a) running an object detector at a plurality of sampling locations, the locations defining a first grid spaced across a first video frame, and recording a hit, to electronic storage, at each location where an object of interest is found; and (b) running the object detector at a further plurality of sampling locations defining a second grid spaced across a succeeding second video frame, the second grid being offset from the first grid, wherein larger points, which have a size of at least 2×
2 points of a fine grained grid, cover the entire first grid and the entire second grid and wherein each of the larger points has one of the sampling locations of the first grid and one of the further sampling locations of the second grid and wherein each of the further sampling locations is offset with respect to a corresponding sampling location of the first grid for a respective larger point and simultaneously running the detector employing parallel processing in addition at one or more further locations on the second frame derived from each location on the first frame at which a hit was recorded. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification