Image processing device for correcting an offset of an image signal

摘要

An image signal sent from an image sensor is input to the inverting terminal of a differential amplifier. An A/D converter converts an output of the differential amplifier to digital output data. A comparison circuit compares the digital output data with a reference value in a dummy bit period to produce a comparison result, for instance, a difference between the digital output data and the reference value. Based on the comparison result, a correction value setting circuit modifies a correction value so that a DC offset becomes closer to the reference value. For example, the correction value setting circuit adds the difference obtained by the comparison circuit to the correction value. A D/A converter converts the modified correction data to an analog voltage, which is input to the noninverting terminal of the differential amplifier.