IMAGE DEFECT INSPECTION METHOD, IMAGE DEFECT INSPECTION APPARATUS, AND APPEARANCE INSPECTION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an image defect inspection method and an image defect inspection apparatus reduced in errors caused by deviation of two image distributions to be compared. SOLUTION: This image defect inspection apparatus includes: a difference image detection part 6 for detecting a gray level difference of corresponding parts of two images; and a defect detection part 8 for comparing the detected gray level difference with a threshold value, and determining a defect when the gray level is larger than the threshold value. The difference image detection part includes: an average calculation part 11 for detecting gray level differences with positive and negative signs to calculate an average value of the gray level differences with the signs; a correction part 12 for calculating a corrected gray level difference with a sign by correcting the gray level differences with the signs by the calculated average value; and an absolute value conversion part 13 for calculating an absolute value corrected gray level difference without a sign from the corrected gray level difference with the sign. The defect detection part 8 compares the absolute value corrected gray level difference with a threshold value. COPYRIGHT: (C)2009,JPO&INPIT