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Methods and apparatus for distinguishing among several visual patterns

  • US 6,021,219 A
  • Filed: 01/07/1997
  • Issued: 02/01/2000
  • Est. Priority Date: 01/07/1997
  • Status: Expired due to Term
First Claim
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1. A method for recognizing a visual pattern to control operation of a video system, said pattern consisting of a locator mark and a selector mark, said selector mark being one of a set of possible selector marks, comprising the steps of:

  • receiving a frame of video data;

    detecting said locator mark within said frame of video data;

    determining a location of said selector mark based on a known size, position and orientation of said selector mark relative to said locator mark by defining bounds of said selector mark based on the known size, position and orientation of said selector mark relative to said locator mark;

    identifying, within said frame of video data, a visual image of said selector mark;

    reducing said visual image of said selector mark to a reduced characterization, said reduced characterization being largely invariant to lighting, distortion and orientation;

    comparing said reduced characterization against members of a set of stored characterizations, each of said stored characterizations being identified with one of said possible selector marks; and

    upon matching said reduced characterization with one of said set of stored characterizations, identifying said possible selector mark as a received selector mark.

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