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Image compression technique

  • US 4,723,298 A
  • Filed: 03/27/1985
  • Issued: 02/02/1988
  • Est. Priority Date: 03/27/1985
  • Status: Expired due to Fees
First Claim
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1. The machine method of automatically compressing a fingerprint image represented by a field of binary pixels comprising the steps of:

  • optically imaging a finger surface or a continuous fingerprint to provide an input image of said fingerprint, said input image being a field of binary value pixels, each of said pixels having either a first value or a second value,designating each mutually exclusive m pixel by n pixel box in said imput image as a unit set, m and n each having a value greater than one,associating a subfield greater than the unit set as an associated subfield for said unit set, the unit set being centered in its associated subfield,assigning a binary value to each of said unit sets as a function of the number and position of the first value pixels and of the second value pixels in said associated subfield, andassigning said binary value of each of said unit sets as the value of a single pixel in an output image, said single pixel having substantially the dimensions of a pixel of said input image to provide said output image no more than one-fourth the size of said input image.

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