METHOD FOR DETECTING POSITION OF OBJECT TO BE MEASURED

摘要

PURPOSE:To detect the center position of a hole rapidly and surely in spite of a small hole by detecting one axial direction center position from a reflected signal minimum value by ultrasonic scanning and determining a virtual center position from the relative position shift of an ultrasonic wave transmitting/receiving element and reflected signal intensity. CONSTITUTION:When a reflected signal is processed by a CPU or the like by executing ultrasonic wave scanning in the X axis direction, a scanned distance/ reflected signal intensity curve is determined and the X coordinate of a hole is calculated from the scanned distance corresponding to a reflected signal minimum value P1. Simultaneously, shift value corresponding to the minimum value P1 is calculated on the basis of a relative positional relation shift/reflected signal curve between an ultrasonic wave transducer and the hole which are previously stored in a memory, the Y coordinates of two pairs of virtual centers of the holes located on comparing positions are determined and one virtual center coodinate is selected from the scanning position. Thus, the center position can be detected rapidly and surely even if the diameter of the hole is small.