| 摘要 |
<p>PURPOSE:To prevent forgery and alteration wherein a main image is substituted because the regional separation from a medium becomes difficult by changing the density at the peripheral part of the main image in a variable density image obtained by an input means by an image processing means. CONSTITUTION:A coefficient group having coefficient distribution as the density distribution at an arbitrary lateral position is prepared. That is, the coefficient group is set so as to be equal to or larger than the number of the longitudinal and lateral pixels of an image 31 and constituted so that the central region is set to '1' the left and right outer peripheries are set to '0' and the intermediate thereof smoothly changes from '1' to '0' toward the outer peripheries. The density difference between the image 31 and the outside thereof is large and the separation and visual confirmation of the boundary thereof is easy. By multiplying the image corresponding to each pixel position and a coefficient, a processed image is obtained. In the processed image, the density difference between the periphery of the image 31 before processing and the left and right outsides thereof is eliminated, that is, the left and right outer peripheries 36 of the image 31 before processing are removed. When outer peripheral part of the image, that is, the boundary of the inside and outside of the image can not be visually confirmed, forgery and alteration become difficult.</p> |
