Hierarchical sudden illumination change detection using radiance consistency within a spatial neighborhood
First Claim
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1. A computer-implemented method for detecting a sudden illumination change (SIC) in a sequence of video frames, comprising:
- receiving a current video frame, of the sequence of video frames;
identifying one or more sets of pixels in the current video frame, wherein each set of pixels is classified as depicting a foreground object;
for each pixel in at least a first one of the sets of pixels;
identifying a radiance value for the pixel and for each pixel within a spatial neighborhood of the pixel, anddetermining, for the pixel, whether the radiance values for the pixel and the pixels in the spatial neighborhood indicate that a sudden illumination change has occurred in a scene depicted by the sequence of video frames; and
upon determining that a majority of pixels in the first set of pixels indicate that a sudden illumination change has occurred, reclassifying one or more pixels in the first set of pixels as depicting a background of the scene in the current frame, wherein the reclassified pixels were classified as depicting scene background in one or more frames prior to the current frame.
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Abstract
Techniques are disclosed for detecting sudden illumination changes using radiance consistency within a spatial neighborhood. A background/foreground (BG/FG) component of a behavior recognition system may be configured to generate a background image depicting a scene background. Further, the (BG/FG) component may periodically evaluate a current video frame to determine whether a sudden illumination change has occurred. A sudden illumination change occurs when scene lighting changes dramatically from one frame to the next (or over a small number of frames).
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Citations
25 Claims
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1. A computer-implemented method for detecting a sudden illumination change (SIC) in a sequence of video frames, comprising:
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receiving a current video frame, of the sequence of video frames; identifying one or more sets of pixels in the current video frame, wherein each set of pixels is classified as depicting a foreground object; for each pixel in at least a first one of the sets of pixels; identifying a radiance value for the pixel and for each pixel within a spatial neighborhood of the pixel, and determining, for the pixel, whether the radiance values for the pixel and the pixels in the spatial neighborhood indicate that a sudden illumination change has occurred in a scene depicted by the sequence of video frames; and upon determining that a majority of pixels in the first set of pixels indicate that a sudden illumination change has occurred, reclassifying one or more pixels in the first set of pixels as depicting a background of the scene in the current frame, wherein the reclassified pixels were classified as depicting scene background in one or more frames prior to the current frame. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A non-transitory computer-readable storage medium containing a program which, when executed by a processor, performs an operation for detecting a sudden illumination change (SIC) in a sequence of video frames, the operation comprising:
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receiving a current video frame, of the sequence of video frames; identifying one or more sets of pixels in the current video frame, wherein each set of pixels is classified as depicting a foreground object; for each pixel in at least a first one of the sets of pixels; identifying a radiance value for the pixel and for each pixel within a spatial neighborhood of the pixel, and determining, for the pixel, whether the radiance values for the pixel and the pixels in the spatial neighborhood indicate that a sudden illumination change has occurred in a scene depicted by the sequence of video frames; and upon determining that a majority of pixels in the first set of pixels indicate that a sudden illumination change has occurred, reclassifying one or more pixels in the first set of pixels as depicting a background of the scene in the current frame, wherein the reclassified pixels were classified as depicting scene background in one or more frames prior to the current frame. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A system comprising,
a video input source configured to provide a sequence of video frames, each depicting a scene; -
a processor; and
a memory containing a program, which, when executed on the processor is configured to perform an operation for detecting a sudden illumination change (SIC) in a sequence of video frames by performing the steps of;receiving a current video frame, of the sequence of video frames, identifying one or more sets of pixels in the current video frame, wherein each set of pixels is classified as depicting a foreground object, for each pixel in at least a first one of the sets of pixels; identifying a radiance value for the pixel and for each pixel within a spatial neighborhood of the pixel, and determining, for the pixel, whether the radiance values for the pixel and the pixels in the spatial neighborhood indicate that a sudden illumination change has occurred in a scene depicted by the sequence of video frames; and upon determining that a majority of pixels in the first set of pixels indicate that a sudden illumination change has occurred, reclassifying one or more pixels in the first set of pixels as depicting a background of the scene in the current frame, wherein the reclassified pixels were classified as depicting scene background in one or more frames prior to the current frame. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification