PROBLEM TO BE SOLVED: To reduce artifact in degree of oxygen saturation occurred in magnified observation.SOLUTION: A light source device 14 of an endoscope system 10 may emit signal light of A emission pattern in which signal light LA1 having center wavelength λA1 and signal light LA2 having center wavelength λA2 are respectively irradiated on a sample and signal light of B emission pattern in which signal light LB1 having center wavelength λB1 and signal light LB2 having center wavelength λB2 are respectively irradiated on the sample. Each of the wavelengths λA1, λA2, λB1, λB2 satisfy λA1-λA2>λB1-λB2. An oxygen saturation degree image creating part 76 comprises an oxygen saturation degree calculation part 83. The oxygen saturation degree calculation part 83 calculates the degree of oxygen saturation in every pixels based on the ratio between each of image signals in an identical pixel which were obtained with reflected light of the signal light LA1 and the signal light LA2 in the case of the A emission pattern and reflected light of the signal light LB1 and the signal light LB2 in the case of B emission pattern. A controlling part 67 executes switch of emission pattern of the light source device 14 between the A emission pattern and the B emission pattern.COPYRIGHT: (C)2015,JPO&INPIT【課題】拡大観察時に表れる酸素飽和度のアーチファクトを低減する。【解決手段】内視鏡システム10の光源装置14は、中心波長λA1の信号光LA1と中心波長λA2の信号光LA2をそれぞれ検体に照射するA発光パターンと、中心波長λB1の信号光LB1と中心波長λB2の信号光LB2をそれぞれ検体に照射するB発光パターンとで信号光を発光可能であり、各中心波長λA1,λA2,λB1,λB2に関して、|λA1-λA2|>|λB1-λB2|を満たす。酸素飽和度算出部83は、酸素飽和度画像生成部76に含まれ、A発光パターンの場合には信号光LA1と信号光LA2の反射光で、B発光パターンの場合には信号光LB1と信号光LB2の反射光で得られた同一の画素の各画像信号の比に基づいて、画素毎に酸素飽和度を算出する。制御部67は、光源装置14の発光パターンをA発光パターンとB発光パターンとで切り替える。【選択図】図2
