Light source device, endoscope system, and method of operating light source device

An endoscope system comprising:

• a light source device including
• a light source that emits light in a plurality of wavelength ranges and is capable of changing a light emission ratio of light in each wavelength range, and
• a light source controller that performs control to emit switching-period-illumination light having a switching-period-light-emission ratio different from a first light emission ratio and a second light emission ratio in a switching period of at least one or more frames in a case where the light source controller performs switching of first illumination light having the first light emission ratio and second illumination light having the second light emission ratio different from the first light emission ratio;
• and
• a processor device that performs processing for first illumination light on a first image obtained from image pickup of an object to be observed illuminated with the first illumination light and performs processing for second illumination light on a second image obtained from image pickup of an object to be observed illuminated with the second illumination light, wherein
• the light source controller performs control to make the switching-period-light-emission ratio correspond to specific color balance at a timing when processing has been switched to the processing for second illumination light from the processing for first illumination light,
• the light source controller performs first switching-period-light-emission control, which emits the switching-period-illumination light while changing the switching-period-light-emission ratio, in the switching period, and
• each of the first illumination light, the second illumination light, and the switching-period-illumination light includes light in at least one wavelength range among the plurality of wavelength ranges.