Method and Apparatus for Projective Volume Monitoring

  • US 20130094705A1
  • Filed: 10/12/2012
  • Published: 04/18/2013
  • Est. Priority Date: 10/14/2011
  • Status: Active Grant
First Claim
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1. A method of detecting objects intruding into a monitoring zone, said method performed by a projective volume monitoring apparatus and comprising:

  • capturing a stereo image from a pair of image sensors;

    correlating the stereo image to obtain a depth map comprising range pixels represented in three-dimensional Cartesian coordinates;

    converting the range pixels into spherical coordinates, so that each range pixel is represented as a radial distance along a respective pixel ray and a corresponding pair of solid angle values within the horizontal and vertical fields of view associated with capturing the stereo image;

    obtaining a set of flagged pixels by flagging those range pixels that fall within a protection boundary defined for the monitoring zone;

    accumulating the flagged pixels into corresponding cells of a two-dimensional histogram that quantizes the solid angle ranges of the horizontal and vertical fields of view; and

    clustering cells in the histogram to detect intrusions of objects within the protection boundary that meet a minimum object size threshold.

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