| 摘要 |
<p>Index marks (21-24) is fixed with predetermined accuracy with respect to image information detector means (1, 2). When image detector means (1) having a narrow field of vision can detect the index marks (21-24), the image information is used to determine the position error of a workpiece (7). When the image detector means (1) is not able to detect the index marks (21-24), image detector means (2) having a wide field of vision detects the index marks (21-24), and the image information is used to determine the position error of a workpiece (7), which in turn is used to correct the relative position between the image detector means (2) and the workpiece (7). The image detector means (1) having a narrow field of vision then seeks image information about the index marks (21-24) to determine the position error of the workpiece (7).</p> |
