PURPOSE: To perform geometrical conversion so that the space of the stroke composing the character patterns is evenly arranged.

CONSTITUTION: The data such as input patterns, inverse number table, etc., is stored in a three-port memory 12. A signal 106 and a signal 107 express read data and a signal 115 expresses write data. A coincidence circuit 16 and a counter 17 are used for measuring the space of the stroke for the character patterns and an adder 18 is used for histogram processing, etc. Multiplexers 21 and 22 select the data read from the three-port memory 12 when the table loop-up processing is performed and gives it as an address. Each module is controlled by the microcode read from a microprogram memory 10 and operates by synchronizing a pipeline clock 100.