Video motion detector with global insensitivity
First Claim
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1. A method for detecting motion in sequential images, said method comprising the steps of:
- defining a target size parameter indicating a minimized area to trigger an alarm,defining a global change parameter,creating a reference frame in dependence upon one or more first images,creating a subsequent frame in dependence upon a second image,dividing said reference frame and said subsequent frame into a plurality of regions;
comparing corresponding regions in said subsequent frame and said reference frame to a threshold thereby forming a difference measure frame composed of difference measure regions,identifying difference measure regions with a value substantially different from other of said difference measure regions,generating an alarm signal when a number of contiguous substantially different difference measure regions is greater than said target size parameter, and said number of contiguous substantially different difference measure regions is less than said global change parameter.
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Abstract
A motion detection system compares the differences between regions in a reference frame and regions in a subsequent frame to a threshold value. A difference frame is defined containing regions indicating which of the corresponding regions in the subsequent frame exceed the threshold difference when compared to the reference frame. Target and global parameters are defined so that a cluster of regions in the difference frame which indicate above threshold differences, must be greater than the target parameter but less than the global parameter for motion to be deemed to have occurred.
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Citations
17 Claims
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1. A method for detecting motion in sequential images, said method comprising the steps of:
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defining a target size parameter indicating a minimized area to trigger an alarm, defining a global change parameter, creating a reference frame in dependence upon one or more first images, creating a subsequent frame in dependence upon a second image, dividing said reference frame and said subsequent frame into a plurality of regions; comparing corresponding regions in said subsequent frame and said reference frame to a threshold thereby forming a difference measure frame composed of difference measure regions, identifying difference measure regions with a value substantially different from other of said difference measure regions, generating an alarm signal when a number of contiguous substantially different difference measure regions is greater than said target size parameter, and said number of contiguous substantially different difference measure regions is less than said global change parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A motion detection system comprising:
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means for creating a reference frame in dependence upon one or more first images, means for creating a subsequent frame in dependence upon a second image, said frames being composed of a plurality of regions; means for comparing regions in said subsequent frame to corresponding regions in said reference frame with respect to a threshold thereby forming a difference frame composed of difference measure regions, means for creating a target parameter indicating a minimized area to trigger an alarm, means for creating a global parameter, means for identifying difference measure regions with values substantially different from other of said difference measure regions, means for creating a motion detection signal when a number of contiguous substantially different difference measure regions is greater than said target size parameter and said number of contiguous substantially different difference measure regions is less than said global change parameter. - View Dependent Claims (10, 11, 12, 13)
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14. A motion detection system comprising:
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means for creating a reference frame in dependence upon a first image, means for creating a subsequent frame in dependence upon a second image, means for comparing said reference frame and said subsequent frame to a threshold factor thereby forming a difference frame, said difference frame comprising a plurality of sub-elements, means for defining a target size parameter indicating a minimized area to trigger an alarm, means for defining a global change parameter, means for identifying sub-elements which have a value substantially different from other of said sub-elements; and means for producing a motion detection signal when a number of contiguous substantially different sub-elements is greater than said target size parameter and said number of contiguous substantially different sub-elements is less than said global change parameter. - View Dependent Claims (15, 16, 17)
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Specification