POSITION DETECTING METHOD

PURPOSE:To attain accurate detection, by performing a recognition while binary coded threshold level and taking an objective detection position when the same checked pattern position is detected at several stages of binary coded threshold levels. CONSTITUTION:A picture is fetched at a TV camera 7, converted into a video signal, and a binary coding signal is obtained at a binary coding circuit 43 and inputted to a line register memory 45 of a picture processor 42. The processor 42 processes whether or not the condition of the sample pattern is to be satisfied to increase a binary coded threshold level of the circuit 43 in a prescribed step of level, allowing to perform recognizing processing at each level. When the same position is detected at a plurality of stages of binary coded threshold level as the position of a characteristic position, the position is taken as the objective detecting position.