PURPOSE: To obtain the coordinate position of a terminal point used for instruction in real time by processing an instruction object photographed by a camera while being still a moving picture.

CONSTITUTION: A frame memory 10 storing picture element data is provided with picture element data from an A/D converter. Concerning picture element data read from the frame memory 10, its part for one horizontal scanning is accumulated by a cumulative adder 16 to be compared with the content of a register 15 by a comparator 17 and at the tune or being more than true content or the register 15, a signal is outputted. Picture element data from the frame memory is multiplied by the content of an address register 13 by a multiplier 18 and the part for one horizontal scanning is cumulative-added by a cumulative adder 19. Then, the value is divided by the value of the cumulative adder 16 by a divider 20 and outputted as an instruction coordinate. When an execution control part 11 stops execution by receiving the output of the comparator 17, the horizontal coordinate of the central coordinate of the terminal point of the instruction object can be obtained from the divider 20 and the vertical coordinate of that can be obtained from an address register 14.