| 摘要 |
PURPOSE:To obtain a good picture reading output by correcting the unevenness in a picture signal resulting from the irregularity in dark current at the time of reading a picture photoelectrically. CONSTITUTION:The picture signal obtained by reading the picture for a line by a CCD 103 has a noise component removed by a sample hold 201, and only a signal component is taken out. A/D converted picture data every picture element by an A/D converter 204 is outputted to a picture signal line 255 as deep white 'OOH' and deep black 'FFF'. The picture data inputted to an offset correction circuit 205 is corrected in dark voltage, further fed to a shading correction circuit 206 and the sensitivity is corrected. Since the shading is corrected by using the black level corrected picture data, the shading resulting from the irregularity in the sensitivity of the respective photodetecting elements of the CCD is corrected. After the black level is.
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