Patent ID: 8231522

Claim:
An electronic endoscope system comprising: a complementary metal-oxide semiconductor (CMOS) image sensor having a plurality of pixels in a two dimensional array, said CMOS image sensor capturing an image of a region of interest under an illumination light and generating image signals; a light source device for repeatedly turning on and off a light source to emit said illumination light, said light source device switching a wavelength of said illumination light between at least two different wavebands every time said light source is turned on; a signal reader for reading out said image signals from all or a part of said pixels while said light source is turned off; and a signal processor for producing two kinds of endoscopic images based on said image signals read by said signal reader, wherein when a time taken to read out said image signals from all said pixels is defined as T, said light source device turns on said light source in every first T/2 period, and said signal reader reads out said image signals from half of said pixels in every second T/2 period.