| 摘要 |
PURPOSE:To accurately detect the position of a reference mark or the like in a multilayer substrate by providing means for irradiating an X-ray on the substrate to form an X-ray fluoroscopic image and performing the binary-coding processing of the X-ray fluoroscopic image thus formed. CONSTITUTION:A control computer (CPU) 21 operates an X-ray generator 31 to generate X-rays 31a. The X-rays 31a are irradiated on a multilayer substrate 37 and the X-ray transmission image of the substrate 37 is obtained by an X-ray television camera 35. An X-ray fluoroscopic image information thus obtained is inputted to an X-ray fluoroscopic image collecting device 49 in the form of video signals and digitized to be stored (45). The X-ray fluoroscopic image information thus stored (45) is averagedly summed (47) and the image density histogram of an averagely summed image information is obtained. The troughs of the background and reference mark portions of the substrate 37 are obtained from the histogram and the above-mentioned image information is binary-coded (43) by the values of the density of the troughs. When no trough is present, it is binary-coded (43) by a threshold value determined in advance. After the image information thus binary-coded is divided (41) into some connected regions, the positions of the centers of the divided regions and the position of a reference mark is calculated from the positions of the centers. |
