Endoscope system, processor device, and method of operating endoscope system

A method of operating an endoscope system comprising:

• a step of causing a light source unit including a plurality of light sources to emit a plurality of kinds of illumination light by independently controlling the plurality of light sources, using a processor;
• a step of acquiring an endoscope image, which is obtained by imaging an observation target using the light source unit, using the processor;
• a step of discriminating a portion having a specific feature in the observation target by performing discrimination processing using the endoscope image, using the processor;
• and
• a step of controlling a start or an end of the discrimination processing on the basis of a change in operation of the endoscope or the endoscope image, using the processor,
• wherein the processor is configured to start the discrimination processing in a case where illumination light from the light source unit is switched to specific illumination light, and end the discrimination processing in a case where the specific illumination light is switched to illumination light other than the specific illumination light.