| 摘要 |
PROBLEM TO BE SOLVED: To suppress error component caused by deviation of relative position between an image reading sensor and a body to be inspected by providing mask data to a picture element based on deviation of the value of each picture element read by means of an image reading sensor and correcting the value of difference by the mask data. SOLUTION: After mask data are obtd., the absolute values of the values of difference between reference images Pa, Pb, Pc and Pd and the inspected image are 1.0, 0.5. 0.1 and 0. Mask correction is performed by reducing the mask data of 0.0, 0.2, 0.2 and 0.0 to these values of difference (however, if the value is negative, it is made zero.) to obtain 1.0, 0.3, 0.0 and 0.0 as data after correction. Here, when a threshold limit value for judgement on abnormal picture element is made 0.2, values for the picture elements Pa and Pb are abnormal and it is judged that there exist stains or defects on these picture elements. |
