| 摘要 |
PURPOSE:To provide a shading corrected signal, from which a defect is removed, by combining a forward time sequential signal and a backward time sequential signal provided by executing cyclic digital high-pass filtering to both the time sequential forward and backward detecting signals. CONSTITUTION:At a signal processor 7 for defect extraction, a digital detecting signal 11 is inputted to a signal copy transmission module 12 and transmitted to forward and backward time sequential cyclic digital high-pass filter modules 13 and 14 and first-stage and second-stage differentiated signal preparation modules 15 and 16, and arithmetic is respectively executed. At the outputs of the differentiated signal preparation modules 15 and 16, those outputs are mutiplied for each signal corresponding to the same picture element number by a multiplication module 17 and respectively transmitted to a decision module 18. Corresponding to the positive/negative state of the signal from the multiplication module 17, any one signal is selected for each picture element and transmitted to a binarizing module 19 as an output signal 20 after shading correction, and the defect is extracted. |
