The endoscope system irradiates illumination light and illuminates a predetermined illumination range, an imaging unit that images a predetermined imaging range of a subject illuminated by the illumination unit, and an image captured by the imaging unit. Further, a low-luminance part detection unit that detects a low-luminance part in the captured image of the subject and a convex part having a predetermined size range are detected based on the information on the low-luminance part detected by the low-luminance part detection unit And a convex size calculation unit.内視鏡システムは、照明光を照射し、所定の照明範囲を照明する照明部と、前記照明部によって照明された被検体の所定の撮像範囲を撮像する撮像部と、前記撮像部により撮像された前記被検体の撮像画像中の低輝度部を検出する低輝度部検出部と、前記低輝度部検出部が検出した前記低輝度部の情報に基づいて所定のサイズ範囲の凸部を検出する凸部サイズ算出部とを具備する。
