LENGTH-MEASURING APPARATUS AND METHOD FOR CONFIRMING ACCURACY OF LENGTH-MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a length-measuring apparatus and a method for confirming accuracy of the length-measuring apparatus whereby length measurement error can be prevented. ;SOLUTION: After a calibration is finished at the length-measuring apparatus, coordinate of each measurement point P1-P9 of a measurement target 22 set on a measurement table 14 is measured by a CCD camera 17 and stored in a RAM 33. Before the length of an object 12 is measured, the coordinate of each point P1-P9 is measured by the CCD camera 17, and compared with the preliminarily stored measured value. If the result of the comparison exceeds a preset allowable range, an error display is made at a CRT 19.;COPYRIGHT: (C)1998,JPO