PURPOSE: To reduce the re-tracing man-hours of a symbol and to improve processing efficiency by heightening a recognition ratio by performing collative recognition between the symbol and an inherent symbol replaced by image-registered inherent symbol and image-registered at a state before unification.

CONSTITUTION: A block at the left side of figure shows an input original figure, and in the figure, no symbol is isolated, and the size of it is not always kept constant, and an inaccurate part due to the blur of a drawing exists. When the arrangement of the symbol is performed, the block goes to the one at an upper right side, and the symbol is isolated(arranged by forming a gap from circumference), and an accurate figure can be obtained, and the size is kept constant, and it goes to the one as designed in logic, therefore, a high recognition ratio can be obtained by performing the recognition of the symbol at such a state. Next, a unification processing is performed, and the block goes to the one shown at the lower right side, and the relevancy of a character(example;123) and attribute in the neighborhood, the recognition of a straight line in the neighborhood with a pipeline, and the coupling of the pipeline with the symbol are performed (referred to circle of broken line). Thereby, it is possible to reduce the re-tracing man-hours of the symbol and to improve the recognition ratio of the symbol more than that in the re-tracing, which improves the processing efficiency as a whole.