| 摘要 |
<p>PURPOSE:To exactly execute light shielding of other part than a desired picture pattern by detecting an outline of the inside by a 1-point portion from an outline of a picture pattern from image information of a color separation plate, and generating a mask in accordance therewith. CONSTITUTION:By bringing a silhouette image to raster scan, one point X0 on a border line of a picture pattern in which '0' and '1' of image information are varied is derived, and thereafter, the next 1 point (x) on the border line is derived from in 8 points of the periphery of the point X0, and by repeating this operation, an outer wall is tracked. In the same way, after deriving a track start point Y0, an inner wall is tracked by deriving successively a point (y). Next, a point sequence (a) of the inside by one from a point sequence (x), and a point sequence (b) of the inside by one from a point sequence (y) are derived. Subsequently, coordinate data of a border line consisting of the point sequences (a), (b) is smoothed, and thereafter, in accordance with its data, a peel-off film is clipped, and at the time of making a positive original plate from a color separation plate, a mask superposed on the color separation plate is generated.</p> |
