Blood information measuring apparatus and method

A blood information measuring apparatus comprising:

• a light source which applies illumination light to a body portion having a blood vessel;
• an imaging device which performs photoelectric conversion of reflected light from said body portion irradiated with said illumination light and outputting an image signal;
• a wavelength tunable element which narrows a wavelength band of said illumination light to be applied to said body portion or said reflected light to be incident on said imaging section;
• and
• a processor, said processor configured for:
• calculating oxygen saturation information based on said image signal;
• driving said wavelength tunable element to switch among a superficial layer wavelength set having a plurality of types of narrow band light in a blue wavelength band, a middle layer wavelength set having a plurality of types of narrow band light in a green wavelength band and a deep layer wavelength set having a plurality of types of narrow band light in a red wavelength band;
• performing preliminary imaging operation, in said preliminary imaging operation, a preliminary image of said body portion in each of said wavelength sets is captured while automatically switching among said superficial layer wavelength set, said middle layer wavelength set and said deep layer wavelength set;
• automatically choosing one of said wavelength sets as an actual imaging wavelength set to be used in actual imaging operation by analyzing a pattern of hypoxic and hyperoxic regions of each of said preliminary images, said actual imaging set wavelength corresponding to said preliminary image in which a mixed degree of said hyperoxic region and said hypoxic region is highest among said preliminary images;
• performing said actual imaging operation in which an actual image is captured with use of said actual imaging wavelength set;
• and
• displaying on a monitor said oxygen saturation information measured in said actual imaging operation,
• wherein the processor detects a location of said body portion in a body cavity, and chooses one of said superficial layer wavelength set, said middle layer wavelength set and said deep layer wavelength set as an abnormality detection wavelength set in accordance with said location, and
• wherein said processor starts said preliminary imaging operation if a mean value of said oxygen saturation level obtained with said abnormality detection wavelength set is less than a threshold value.