| 摘要 |
PURPOSE:To express the change in the contrast of an original image with fidelity by using a coordinate being the parallel movement of a coordinate of a conversion picture element T on each side along the sides of a rectangle formed by four adjacent original picture elements as reference picture elements and calculating and averaging the gradation of the reference picture element at each side based on the gradation of the original picture element and the length of each side. CONSTITUTION:A position calculation section inputting conversion rates P, q of the conversion picture element face with respect to an original picture element face is provided in each direction of sides of a rectangle PQRS comprising four adjacent original picture elements P-S. The X-Y coordinate axis is assumed while using the gravity center of the rectangle as an origin, a reference part of a conversion picture element plane is matched with a prescribed part of the original picture element plane, the position of the conversion picture element forming the conversion picture element plane is specified on the X-Y coordinate and a position calculation section calculates the position of the conversion picture element. A coordinate (Xt, Yt) of the conversion picture element calculated by the position calculation section is inputted to a distance calculation section, the coordinate (Xt, Yt) is moved in parallel with each side of the rectangle PQRS and points of each side are used as reference picture elements UPQ, UQR and USP. |
