PROBLEM TO BE SOLVED: To provide an endoscope system capable of posteriorly validating whether or not pre-photography is performed under an appropriate condition, a processor device, and an operation method of the endoscope system.SOLUTION: The endoscope system comprises: an image acquisition section that includes an oxygen saturation calculation part 73 for calculating an oxygen saturation of an observation object using an LUT (a Look-up Table) 75 and, prior to the calculation of the oxygen saturation, acquires a correction image 86 acquired by capturing the observation object; an oxygen saturation correction amount calculation section 82 that calculates an oxygen saturation correction amount with respect to the oxygen saturation using the correction image 86; an oxygen saturation correction section 84 that corrects the oxygen saturation calculated by the oxygen saturation calculation part 73, in accordance with the oxygen saturation correction amount; and a storage section 92 that stores the correction image 86 and the oxygen saturation image 96 representing the oxygen saturation after the correction, in association with each other.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2017,JPO&INPIT【課題】プレ撮影が適切な条件下で行われたかどうかを事後的に検証することができる内視鏡システム、プロセッサ装置、及び内視鏡システムの作動方法を提供する。【解決手段】内視鏡システムは、LUT75を用いて観察対象の酸素飽和度を算出する酸素飽和度算出部73を有し、酸素飽和度の算出に先立って観察対象を撮像して得る補正用画像86を取得する画像取得部と、補正用画像86を用いて酸素飽和度に対する酸素飽和度補正量を算出する酸素飽和度補正量算出部82と、酸素飽和度補正量にしたがって酸素飽和度算出部73が算出した酸素飽和度の補正をする酸素飽和度補正部84と、補正用画像86と、補正後の酸素飽和度を表す酸素飽和度画像96とを関連付けて保存する保存部92と、を備える。【選択図】図3