| 摘要 |
PURPOSE:To improve the detecting accuracy of a dot image and to perform the optimum moire elimination by preventing unrequited smoothing processing from being performed in linear arrangement. CONSTITUTION:The detecting accuracy of the dot image can be improved by computing the spatial frequency characteristic of an input image signal by a CPU 104, and detecting the presence/absence of the dot structure of an input image and the period of dot structure from the classification and accumulation result of a document image at every spatial frequency. The optimum filters is selected from cut filters with narrow band width registered on a ROM 105 according to the calculated spatial frequency characteristic of the input image, and it is set on a filtering arithmetic part 106. The filtering arithmetic part 106 performs spatial filtering processing on the input image by a set filter. |
