Patent ID: 9131183
Filing Date: 2015-09-08
Classification: H04N

Abstract:
1. An image signal processing apparatus comprising: a clock generator configured to generate a clock signal which has been subjected to spread spectrum modulation by using a digital modulation signal and to supply the clock signal to a photoelectric conversion element; an AD converter configured to perform AD conversion on an image signal which is obtained by the photoelectric conversion element; a noise detector configured to detect and calculate a noise amplitude of a noise signal which is caused by the spread spectrum modulation of the clock signal and is included in the image signal that has been AD converted; and a correction circuit configured to calculate a correction factor based on the noise amplitude detected by the noise detector, to generate a correction signal by multiplying the digital modulation signal by the correction factor generated based on the detected noise amplitude, and to superimpose the correction signal onto the image signal at an input side or an output side of the AD converter, wherein the noise detector detects the noise amplitude by detecting a voltage difference between a peak voltage and a bottom voltage, and wherein the peak voltage is given by a mean voltage of a designated period of time before and after a peak of the image signal, and the bottom voltage is given by a mean voltage of a designated period of time before and after a bottom of the image signal.