| 摘要 |
PURPOSE:To prevent an erroneous defective detection attributable to a process, alignment or the like and contrive efficiency of the defective detection by a method wherein a sign representing an edge direction is given to each pixel and compared with a tamplate in which a distribution consisting of signs is beforehand stored. CONSTITUTION:Design data stored in a magnetic disc 11 are converted into dot data by a bit map generator 12 and stored in a bit map memory 13. Features of a pattern are extracted by a feature extracting circuit 14 to be supplied to a defective detecting circuit 15. While, sensor data of a CCD sensor 16 are converted into digital data in an A/D converter 17 and stored in a buffer memory 18 to be supplied to the defective detecting circuit 15. Based on the sensor data stored in the buffer memory 18, the defective detecting circuit 15 gives signs representing an edge direction to each pixel. Further, a tamplate corresponding to the feature extracted by the feature extracting circuit 14 is selected and compared with a distribution of given signs to detect defects. Thus, an attempt is made to prevent the erroneous defective detection due to a process, a positioning, or the like and to contrive efficiency of the defective detection. |
