| 摘要 |
<P>PROBLEM TO BE SOLVED: To specify a ground and a region except for it based on local data of an input image and to apply image quality improvement (exclusion of rear side projection) methods suitable for respective regions so as to improve image quality of the whole image. <P>SOLUTION: The region surrounding a black character is extracted based on an image feature of the input image. A high luminance pixel group region of a block where an evaluation function based on the number of pixels and a luminance value is the largest is selected as ground reference from the character surrounding region by a block division processing, and an average value is set to be an estimated ground color. The region considered to be the ground is extracted from the input image based on the estimated ground color, and the pixel of the region is substituted for an estimated representative background color. Thus, image quality is improved. Meanwhile, a processing for substituting a rear side projection pixel for the estimated background color is applied and rear side projection is performed and image quality is improved while the local background color is estimated with respect to the region except for the ground of the input image. Gradation correction is performed on the region so that gradation discontinuity with the ground region does not occur. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
