| 摘要 |
PURPOSE:To improve position detection accuracy of a mark and to enable prevention of misdetection. CONSTITUTION:A position of an edge of each of a plurality of marks is obtained by using either maximum values KA, KB, KC or minimum values Ka, Kb of data D2 of a differential value of data D1 comprised of an average strength value, and a position of a mark group is obtained by adding or subtracting half a mark width to or from a position of a mark edge group obtained in accordance with a position of each edge of the marks. Thereby, it is possible to detect a position of a mark group surely at high precision even when one edge of a mark is obtuse. |
