| 摘要 |
<p>The optical black portion is extracted from the output of a CCD imaging device (1), and the clamp level of each line is found by an integrating/averaging circuit (6). The absolute value of the difference between the clamp levels of two consecutive lines is calculated by a comparing circuit (10). According to whether or not the calculated absolute value is in a predetermined range, either the clamp level of the line or the clamp level updated by a predetermined value is selected by a selector (16). The clamp level outputted from the selector (16) is subtracted from the output of the CCD imaging device (1). Therefore the optical black portion of the output of an imaging device can be clamped at the black level by means of simple hardware without causing line flicker.</p> |
