The present technique pertains to an endoscope system in which the resolution and the S/N ratio are adjusted with good balance in accordance with image-capturing conditions, and in which the processing load can be varied in accordance with image-capturing conditions. The present technique also pertains to a method for operating the endoscope system, and a program. A low-pass image comprising low-pass components and a high-pass image comprising high-pass components are extracted from an image signal of the body cavity for which an image has been captured by the endoscope device. When the low-pass image is reduced at a predetermined reduction ratio and processed to increase quality, the image is enlarged by an enlargement ratio corresponding to the reduction ratio. At this point, when the brightness during image-capturing is sufficient on the basis of condition information indicating the image-capturing state, and the high-pass component does not have a high noise component content, the low-pass image and the high-pass image are added together and outputted as an output image. When the brightness during image-capturing is insufficient on the basis of the condition information and the high-pass component has a high noise component content, only the low-pass image is outputted as an output image. The present technique can be applied to an endoscope system.La présente technique concerne un système d'endoscope dans lequel la résolution et le rapport S/B sont ajustés de façon équilibrée, selon des conditions de capture d'image, et dans lequel la charge de traitement peut varier en fonction des conditions de capture d'image. La présente technique concerne également un procédé de fonctionnement du système d'endoscope et un programme. Une image basse fréquence comportant des composantes basse fréquence et une image haute fréquence comportant des composantes haute fréquence sont extraites d'un signal d'image de la cavité du corps pour laquelle une image a été capturée par le d
