| 摘要 |
PURPOSE:To measure a relative position with high accuracy without being influenced by a variation of a distance between a camera and a mark, by operating the magnification in an optical system of the camera loaded on a moving body in order to read the mark put on a prescribed position. CONSTITUTION:On the fixed side, a mark 10 is provided, and on a moving body side, a line scanning camera 14 is loaded. The camera 14 outputs a binary- coded picture read-out signal 16, and a read-out clock 18 generated in accordance with a picture element. An operating part 44 operates a position M of the center of the mark 10, by M=m+n/2, in accordance with a counting value (m) of a down-counter 30, operates magnification D/n in an optical system of the camera 14 from mark width D and a counting value (n) of an up-counter 34, and calculates a distance (l) between the optical axis (center) of the camera and the center of the mark 10, by l=D(M-N/2)n. |
