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Character reader

  • US 4,630,308 A
  • Filed: 07/20/1984
  • Issued: 12/16/1986
  • Est. Priority Date: 08/04/1983
  • Status: Expired due to Fees
First Claim
Patent Images

1. A pattern recognition apparatus comprising:

  • (a) means for scanning an unknown pattern and providing a video signal corresponding to an image of the unknown pattern;

    (b) binary encoding means for dividing the image into an array of pixel elements and converting the video signals into binary values using a threshold level, each of the binary values corrsponding to a respective one of the pixel elements;

    (c) feature extracting means for converting the binary vlaues corresponding to the pixel elements into segments corresponding to the image, each segment being a horizontal series of pixel elements having a first binary value;

    (d) memory means for storing the segments corresponding to the image and data representing a pluraltiy of standard patterns K, the data representing each one of the standard patterns comprising;

    (i) a standard bit matrix BSK (i,j) derived by dividing an image of the standard pattern into a specified array of meshes, each one of the meshes corresponding to a respective element of the matrix BSK (i,j), each element of the matrix having the first or a second binary value depending respectively upon whether or not a portion of the standard pattern is present in the corresponding mesh, the matrix BSK (i,j) being reducible to a corresponding cluster expression matrix having mask elements, blank elements, and transformation elements of a transformation chain,(ii) a mask bit matrix BMK (i.j) having elements corresponding to respectivel ones of the meshes of the specified array, each element of the matrix BMK (i,j) having the second or the first binary value depending respectively upon whether or not the element is a mask element,(iii) transformation bit matrices D1, D2, D3, D4, D5, D6, D7 and D8 each having elements of a first binary value if the elements of D1 to D8 correspond respectively to a present transformation element at the left end of a horizontal transformation chain, at the lower left end of a diagonal transformation chain, at the lower end of a vertical transformation chain, at the lower right end of a diagonal transformation chain, at the right end of a horizontal transformation chain, at the upper right end of a diagonal transformation chain, and at the upper end of a vertical transformation chain, at the upper left end of a diagonal transformation chain;

    e. operating means for performing preprogrammed operations on the data stored in the memory means inclduing;

    (i) means for comparing a width and a height of the unknown pattern with the width and height of a search frame,(ii) means for dividing the image of the unknown pattern into the specified array of meshes and deriving a bit matrix B(i,j) of the image having elements corresponding to reapective ones of the meshes of the specified array, each element of the matrix B(i,j) having the first or the second binary value depending respectively upon whether or not a portion of the unknown pattern is present in the corresponding mesh,(iii) means for matching the unknown pattern to one of the standard patterns by computing the deviation DK (B) between the unknown pattern and each one of the standard patterns, the deviation DK (B) being computed by performing a prescribed operation on at least a corresponding block of the matrix B(i,j) and the matrices BSK (i,j), BMK (i,j), D1 to D8, representing each one of the standard patterns wherein the prescribed operation is defined as ##EQU3## where DK is a transformation matrix operator comprising transformation bit matrices D1 to D8 for the standard pattern K.

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