| 摘要 |
PURPOSE: To automatically detect the position of a defective picture element due to a scanner in a digital picture. CONSTITUTION: A list of tentative defect positions is stored in a buffer 40. A controller 34 adds an entry in each scanning of a document, increases a tentative defect position counting value when documents having picture elements of the same color on the same position are continued, and when the color of the picture element on the position is changed, the count value is reduced or turned to '0'. When the count value exceeds a threshold, the tentative defect is outputted as a real defect 42. When the size of a memory is restricted, the number of enteries in the defect list is restricted to a certain maximum size, a tentative defect position is added to the list only when an entry can be used. |
