Adaptive illuminance filter in a video analysis system
First Claim
1. A computer-implemented method for removing false-positive foreground pixels from a video frame, comprising:
- extracting, via one or more processors, a foreground image from the video frame using a background model image;
determining, based on at least the foreground image and portions of the background model image used as a proxy for an illuminance component of the foreground image, an approximated reflectance component of the foreground image, wherein the portions of the background image are pixels that correspond to respective pixels in the foreground image and wherein the approximated reflectance component provides approximated reflectance values for the respective pixels in the foreground image; and
removing from the foreground image pixels having approximated reflectance values less than a first threshold value.
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Abstract
Techniques are disclosed for removing false-positive foreground pixels resulting from environmental illumination effects. The techniques include receiving a foreground image and a background model, and determining an approximated reflectance component of the foreground image based on the foreground image itself and a background model image which is used as a proxy for an illuminance component of the foreground image. Pixels of the foreground image having approximated reflectance values less than a threshold value may be classified as false-positive foreground pixels and removed from the foreground image. Further, the threshold value used may be adjusted based on various factors to account for, e.g., different illumination conditions indoors and outdoors.
52 Citations
20 Claims
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1. A computer-implemented method for removing false-positive foreground pixels from a video frame, comprising:
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extracting, via one or more processors, a foreground image from the video frame using a background model image; determining, based on at least the foreground image and portions of the background model image used as a proxy for an illuminance component of the foreground image, an approximated reflectance component of the foreground image, wherein the portions of the background image are pixels that correspond to respective pixels in the foreground image and wherein the approximated reflectance component provides approximated reflectance values for the respective pixels in the foreground image; and removing from the foreground image pixels having approximated reflectance values less than a first threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A non-transitory computer-readable storage medium storing instructions, which when executed by a computer system, perform operations for analyzing a scene depicted in an input stream of video frames captured by a video camera, the operations comprising:
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extracting a foreground image from the video frame using a background model image; determining, based on at least the foreground image and the portions of the background model image used as a proxy for an illuminance component of the foreground image, an approximated reflectance component of the foreground image, wherein the portions of the background image are pixels that correspond to respective pixels in the foreground image and wherein the approximated reflectance component provides approximated reflectance values for the respective pixels in the foreground image; and removing from the foreground image pixels having approximated reflectance values less than a first threshold value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system, comprising:
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a processor; and a memory, wherein the memory includes an application program configured to perform operations for removing false-positive foreground pixels from a video frame, the operations comprising; extracting a foreground image from the video frame using a background model image, determining, based on at least the foreground image and portions of the background model image used as a proxy for an illuminance component of the foreground image, an approximated reflectance component of the foreground image, wherein the portions of the background image are pixels that correspond to respective pixels in the foreground image and wherein the approximated reflectance component provides approximated reflectance values for the respective pixels in the foreground image, and removing from the foreground image pixels having approximated reflectance values less than a first threshold value. - View Dependent Claims (20)
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Specification