Patent ID: 8790251

Claim:
An electronic endoscope system comprising: a light applying section for applying at least three types of narrow band light having wavelengths within 400 nm to 600 nm as illumination light to an internal body part containing a blood vessel, two types of the illumination light out of the three types of the illumination light being narrow blue band light and narrow green band light; an image sensor for capturing an image of the internal body part irradiated with the illumination light; a blood vessel information obtaining section for obtaining blood vessel information based on a narrow band signal corresponding to the three types of the narrow band light, the blood vessel information including a depth of the blood vessel and a hemoglobin index, a brightness ratio calculating section for calculating a first brightness ratio between the first narrow blue band signal and the second narrow blue band signal, and a second brightness ratio between the third narrow green band signal and the second narrow blue band signal; and a memory for storing in advance a correlation between the depth of the blood vessel and the hemoglobin index with respect to the first and second brightness ratios, wherein the three types of the illumination light includes first narrow blue band light, second narrow blue band light, and third narrow green band light; and the narrow band signal corresponding to the three types of the narrow band light includes a first narrow blue band signal, a second narrow blue band signal, and a third narrow green band signal; wherein, the blood vessel information obtaining section obtains based on the correlation stored in the memory the depth of the blood vessel and the hemoglobin index from the first and second brightness ratios.