PURPOSE: To prevent adverse influence to graphic recognition which is subsequently executed by eliminating the acute shape of a drawing and document, and shaping a vectorized part so as to keep a original acuteness and to in a recognition device which optically reads the drawing and document or the like, inputs them to a computer and vectorizes them.

CONSTITUTION: A picture is inputted in a first process. A contour graphic is extracted from the picture in a second process. The contour graphic is contour- vectorized in a third process. A contour shaping process 4 is added after the processes. The contour shaping process 4 judges whether a noticed acute refraction point requires shaping or not by prescribed judgment reference and shapes the acute refraction point by a prescribed method if need.