| 摘要 |
PURPOSE:To prevent omission of reading and duplicate reading effectively by setting a white threshold width as the length of opening of a comblike electrode corresponding to the white threshold width when it is deviated to the black side by a preset correction value. CONSTITUTION:In an coplanar type image sensor, for instance, the width W and slit width l of an opening 2 are set to 10mum respectively and reading of picture information of 4-line pair/mm is performed. When the white and black threshold level SL was determined, supposing that the time required to change from black to white is t1, the time required to change from white to black is t2, and the time required to change next from black to white is t3 when reading 4 line pair/mm at 5ms/line equivalent, the white threshold width TW becomes t2-t1, and the black threshold width becomes t3-t2. When a light response output of the image sensor is binary-coded by the level SL, the condi tion for eliminating omission of reading and duplicate reading wherever is the timing of reading of the picture information is TW=TB=5ms.
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