| 摘要 |
PROBLEM TO BE SOLVED: To improve the detection accuracy of a soldered part by matching an alignment mark on the side of a single-sided circuit board and an alignment mark on the side of a double-sided circuit board to achieve an accurate detection of the position of the alignment marks. SOLUTION: A model single-sided circuit board having an alignment mark soldered thereon is irradiated previously with X-rays of an X-ray source 1 to store an image into an image memory 4a for one side. In detection, a double- sided circuit board having an alignment mark soldered thereon is irradiated with the X-rays to store the image into an image memory 4b for two sides. More than one alignment marks are carved from the respective X-ray images of the single-sided board and the double-sided board and undergoes a binary coding to obtain correct alignment mark images. A calculator 5 determines the coordinates of the centers of gravity of the respective images from the binary-coded image. Then, both the alignment marks are made to match each other by computing a transformation of coordinate coefficient and a coordinate difference is determined to obtain a differential image. Thus, alignment mark positions of the single-sided board and the double-sided board can be detected accurately thereby improving the detection accuracy of a soldered part. |
