IMAGE SIGNAL PROCESSING APPARATUS, IMAGE SCANNIG APPARATUS AND METHOD FOR PROCESSING IMAGE SIGNAL

摘要

A signal processing circuit 4 includes a clock circuit 24 which generates a clock signal which has been subjected to spread spectrum modulation and supplies the clock signal to a photoelectric conversion element; a AD converter 15 which performs AD conversion on an image signal obtained by the photoelectric conversion element; a noise detecting circuit 21 which detects a noise amplitude of a noise signal that is caused by the spread spectrum modulation of the clock signal and is included in the image signal which has been AD converted; and an analog correction circuit 23 and an digital correction circuit 22 that calculate a correction factor based on the noise amplitude, generate a correction signal by multiplying the digital modulation signal by the correction factor, and superimpose the correction signal onto the image signal at an input side or an output side of the AD converter.