Patent ID: 9433375
Filing Date: 2016-09-06
CPC Classification: A61B,G06T

Claim Text:
1. An endoscope system comprising: a light source that applies first illumination light to an object, said first illumination light having a first wavelength band in which oxyhemoglobin and deoxyhemoglobin have different absorption coefficients, wherein said light source further applies second illumination light having a second wavelength band and third illumination light having a third wavelength band to said object; an imaging device that images said object and obtaining first image information under irradiation with said first illumination light, wherein said imaging device further obtains second image information under irradiation with said second illumination light and third image information under irradiation with said third illumination light; a processing circuitry including a memory for storing a correlation among an oxygen saturation level of blood, a first intensity ratio being an intensity ratio of each pixel between a first image information pair chosen out of said first to third image information, and a second intensity ratio being an intensity ratio of each pixel between a second image information pair different from said first image information pair, wherein said correlation is represented in the form of a two dimensional table in which contour lines representing the oxygen saturation level of blood are defined in two-dimensional space and a position and a shape of the contour lines are determined by physical simulation of light scattering, the processing circuitry configured for: obtaining spectrum change information relating to change in a spectrum of said first illumination light; changing said correlation based on said spectrum change information; and calculating said oxygen saturation level by using said first, second, and third image information and said changed correlation, wherein a cumulative lighting time of said lighting section is used as said spectrum change information, and wherein said memory is configured to store first and second correlations, wherein the first correlation is used when the cumulative lighting time is less than a predetermined value and the difference in the absorption coefficient between oxyhemoglobin and deoxyhemoglobin is within a predetermined range and the second correlation is used when the cumulative lighting time equals or exceeds the predetermined value and the difference in the absorption coefficient between oxyhemoglobin and deoxyhemoglobin is out of the predetermined range.