PURPOSE: To enable accurate inspection processing or other operations by comparing a radiolucency image position of a reference mark provided on a mounted circuit board with the position of the reference mark taught previously to allow the elimination of a deviation of the circuit board simply.
CONSTITUTION: When a substrate 12a yet to be mounted is located at a position of detection, an optical detector 25 is moved to a photographing position to photograph a reference mark of the substrate 12a. A mark image undergoes an image processing 14 and the resulting position data is stored into a teaching image memory 26. Then, when a mounted substrate 12 is conveyed and positioned at a position the same as that of the substrate 12a, an X-ray source 11 of the transmission X-ray image detector is moved to take a transmission X-ray image of the reference mark of the substrate 12. An image data thus obtained undergoes an image processing 14 to detect a position. The position is compared with the position of a mark of the substrate 12a stored 26 and when both the positions do not coincide, a coordinate conversion matrix associated with a deviation between both the substrates is derived to move an image to the position where the both overlap. Thus, images of both the substrates can be compared directly.
SHONO HIROBUMI
HORIGUCHI SHIRO
