| 摘要 |
<P>PROBLEM TO BE SOLVED: To quickly detect the angle of inclination(rotation) of a document image fetched in an inclined(rotated) state whose pixel values are unknown, that is, either concentration or luminance. <P>SOLUTION: A binary threshold is selected for input image data on an x-y plane, and whether the pixel values of the input image data are concentration or luminance is decided from the number of pixels in an upper rank and lower rank with the value as a reference. Also, the background part of an image is decided based on the binary threshold, and an added pixel value is set for pixels corresponding to an object whose background part is removed according as the pixel values are concentration or luminance, and parameter transformation to (angle, distance) coordinates called Radon transformation or Hough transformation is executed from the (x, y) coordinates of each pixel and the set added pixel value, and an angle/distance parameter chart whose linearity is easily extractable is prepared. The angle where straight lines concentrate is detected as the angle of inclination(rotation) of the image from the angle/distance parameter chart. Thus, it is possible to quicken a processing speed without decreasing performance by removing the background part. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
