| 摘要 |
<p>PROBLEM TO BE SOLVED: To guarantee reversibility of a specified pixel in the case of decoding and to prevent image degradation of a contour part by storing position, density value information as a compressed result for the specified pixel to which high space frequency is given on an inputted image. SOLUTION: An inputted 256 gradation image is scanned, a specified image to satisfy a specified condition is detected and its position and density value are stored by a specified pixel detecting means 10. Namely, when characters are overwritten on a dark image, the brightest part is generally detected as the specified pixel, the reversibility of image quality to constitute the characters is guaranteed and the image degradation of the characters is prevented. The density value is replaced with a specified density value by receiving the position and density value information of the inputted image and the specified pixel, an intermediate image by which high compression rate is achieved without image degradation is generated by an intermediate image generating means 11, the intermediate image is compressed by receiving the position and density value information of the intermediate image and the specified pixel, its result is calculated, defined as a compressed result of the intermediate image, the result, the position of the specified pixel and the density value are outputted as the compressed results by an image compressing means 12.</p> |
