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Conversion of Image Resolution Disclosure Number: IPCOM000034849D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27

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Asano, H Nakajima, M Shirai, H [+details]


This article describes an algorithm for converting a resolution of an original image by comparing the gray levels of picture elements (pels) of the original image with the plural dither matrices to generate binary data which result from the comparison and determining the number of black and white pels in the converted image. Fig. 1 shows an original image 1, dither matrices 2, 3 and 4, resultant binary data 5, 6 and 7, and a converted image 8. The values in the original image 1 and the dither matrices 2, 3, and 4 are represented by hexadecimal notation (X). For example, the value X'65' at a pel position (2, 2) in the original image 1 means the binary value '01100101'. As shown in Fig. 2, gray levels between a real white level and a real black level are divided into 256 levels. Fig.