Endoscope system, processor device of endoscope system, and image processing method

An endoscope system, comprising:

• a light source device that includes a light emitting unit, which emits two or more illumination light beams including first illumination light and second illumination light having different wavelength regions, and a light amount ratio setting unit, which sets a light amount ratio between the first illumination light and the second illumination light, and that irradiates a subject with the first illumination light and the second illumination light based on the light amount ratio set by the light amount ratio setting unit;
• an electronic endoscope configured to acquire two or more color signals having different pieces of color information by receiving and imaging return light from the subject using an imaging element;
• and
• a processor device that generates an endoscope image based on a signal obtained by imaging, wherein the processor device includes
• a multi-color image generation unit configured to generate a multi-color image formed from calculated values obtained by performing predetermined calculation for each pixel using the two or more color signals;
• and
• a blood vessel extraction image generation unit configured to generate at least one of a first layer blood vessel extraction image, which is obtained by extracting a first layer blood vessel at a specific depth from the multi-color image, and a second layer blood vessel extraction image, which is obtained by extracting a second layer blood vessel at a position deeper than the first layer blood vessel from the multi-color image, by performing blood vessel extraction processing, which differs depending on the light amount ratio, on the multi-color image.