| 摘要 |
PURPOSE:To perform sufficiently while balance and shading correction by inserting a reference pulse to a blanking period of a video signal before a preamplifier, detecting the pulse after the preamplifier to obtain a gain of the preamplifier and changing the shading correction quantity based on the result. CONSTITUTION:The gain of analog/digital gain converters 2b, 70 is set to a preset value under the standard lighting condition, shading information stored in a memory 10 is read and the shading quantity included in a video signal (c) is eliminated by a subtractor 30. When the lighting condition changes, a white object is picked up for the image to take white balance and an AWB control circuit 80 controls the gain of the analog gain converter 2b to bring a video signal (v) to a prescribed value. In this case, an SG control circuit 60 measures a level of a reference pulse inserted into the video signal (c) to control the gain of the digital gain converter 70.
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