| 摘要 |
PROBLEM TO BE SOLVED: To detect the position of a mark formed on an object with accuracy. SOLUTION: An image forming optical system picks up the image of a mark formed on an image picking-up surface. With respect to the image of the mark thus picked up, a specific algorithm which can realize high position detecting accuracy in the case where the image of the mark is influenced by the aberration of the optical system is selected out of a plurality of position detecting algorithms in accordance with the influence of the aberration exerted upon the image of the mark (steps 126-128). Then, the position of the mark is detected by analyzing the picked-up image of the mark by using the selected specific algorithm (steps 129 and 130). Consequently, the deterioration of the position detecting accuracy caused by the influence of the aberration exerted upon the picked-up image of the mark can be suppressed and the position of the mark can be detected stably with accuracy. |
