| 摘要 |
PURPOSE:To detect the linear scratches with high accuracy by performing a contrast emphasizing operation to carry out a product sum operation with the (linear) image elements noted in four directions, to increase the scratch density toward the scratch, and to reduce the noise level of a non-defect part. CONSTITUTION:Plural (linear) image elements are combined in four directions against the gradation value S0 of a noted image element and the gradation values S1 - Sm of the secondary peripheral image elements of (m X m). Then the product sum of gradation is secured for the plural (linear) image elements of four directions. At the same time, the minimum gradation value (black scratch) and the maximum gradation value (white scratch) are obtained in four directions respectively. Therefore the scratch density can be integrated toward the scratch direction when a scratch is detected and the noise level can be reduced at a non-defect part. Thus the S/N is improved and the contrast is emphasized. As a result, the linear scratches can be detected with high accuracy. |
