RECOGNITION OF COMPONENT

PURPOSE:To make it possible to measure stably the position of the point of a transmitting cylindrical body by a method wherein a window frame part is set on the part to be measured of an image using a picture signal and a detection of the edge of the transmitting cylindrical body is performed on one side of the quadrangle of the window frame on the opposite side to the direction of the point of the previously given transmitting cylindrical body. CONSTITUTION:A window frame part 22 is set on a part to be measured of an image 21 using a picture signal preserved in a memory and a detection of the edge of a transmitting cylindrical body is performed on one side 24 of the quadrangle of the window frame on the opposite side to the direction 23 of the point of the previously given transmitting cylindrical body. Within a plurality of the measured positions of the point, a detection of the edge is performed in the direction vertical to the direction of the point at a position of a previously given distance toward the opposite direction 36 to the direction 23 of the point of the previously given transmitting cylindrical body from the position 37 of the point nearest the one side 24, on which the detection of the edge is performed, of the quadrangle of the window frame, a test of the form of the edge is made and in the case where the form in an error, the error is recognized as the error of the form.