# US 2014/0192362 A1 · Optical measurement apparatus and calibration method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192362 A1 - Document ID: US20140192362A1 - Status: Published application - Kind: A1 - Application number: 14/206,042 - Filed: 2014-03-12 - Published: 2014-07-10 - Earliest claimed: 2011-09-20 - Assignees: Olympus Corporation - Applicants: Olympus Corporation - Inventors: Hideyuki TAKAOKA; Ryosuke ITO - Web page: https://patentgrep.com/patent/US20140192362A1 ## CPC - G01N 21/47: Scattering, i.e. diffuse reflection (G01N21/25, G01N21/41 take precedence {G01N21/55 takes precedence}) - A61B 1/00057: {provided with means for testing or calibration} - A61B 1/042: {characterised by a proximal camera, e.g. a CCD camera} - A61B 1/055: having rod-lens arrangements - A61B 5/0075: {by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence)} - A61B 5/0084: {for introduction into the body, e.g. by catheters (A61B5/1459 takes precedence)} - G01N 21/274: {Calibration, base line adjustment, drift correction} - G01N 21/474: {Details of optical heads therefor, e.g. using optical fibres} - G01N 21/49: within a body or fluid - G01N 21/55: Specular reflectivity - G01N 2021/4709: {Backscatter} - G01N 2021/4742: {comprising optical fibres} - G01N 2021/4769: {Fluid samples, e.g. slurries, granulates; Compressible powdery of fibrous samples} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An optical measurement apparatus includes: a recording unit that records therein a value of a ratio of a first detection intensity to a second detection intensity, the first detection intensity being an intensity of the returned light detected when a first medium having a refractive index that is the same as that of a specimen is irradiated with illumination light by a measurement probe, and the second detection intensity being an intensity of the returned light detected when a second medium is irradiated with the illumination light by the measurement probe; and a calculation unit that calculates, from a product of a third detection intensity and the value of the ratio, a background intensity of background light to be used in correcting the returned light from the specimen, the third detection intensity being an intensity of the returned light detected when the second medium is irradiated with the illumination light. ## Claims ### Claim 1 An optical measurement apparatus, comprising: a measurement probe that irradiates a specimen with illumination light and optically receives returned light of the illumination light reflected and/or scattered from the specimen; a detection unit that detects the returned light optically received by the measurement probe; a recording unit that records therein a value of a ratio of a first detection intensity to a second detection intensity, the first detection intensity being an intensity of the returned light detected when a first medium having a refractive index that is the same as that of the specimen is irradiated with the illumination light by the measurement probe and detected in a state of not including the returned light from the first medium, and the second detection intensity being an intensity of the returned light detected when a second medium is irradiated with the illumination light by the measurement probe and detected in a state of not including the returned light from the second medium; and a calculation unit that calculates, from a product of a third detection intensity and the value of the ratio, a background intensity of background light to be used in correcting the returned light from the specimen, the third detection intensity being an intensity of the returned light detected when a third medium is irradiated with the illumination light by the measurement probe and detected in a state of not including the returned light from the third medium. ### Claim 2 (depends on 1) The optical measurement apparatus according to claim 1, wherein the calculation unit subtracts the background intensity from a detection intensity of the returned light from the specimen detected by the detection unit when the measurement probe irradiates the specimen with the illumination light. ### Claim 3 (depends on 2) The optical measurement apparatus according to claim 2, wherein the detection unit has a spectrometer, and the first detection intensity, the second detection intensity, and the third detection intensity are values detected for each wavelength spectrally dispersed by the spectrometer. ### Claim 4 (depends on 1) The optical measurement apparatus according to claim 1, wherein the first medium is water. ### Claim 5 (depends on 1) The optical measurement apparatus according to claim 1, wherein the second medium is air. ### Claim 6 (depends on 1) The optical measurement apparatus according to claim 1, wherein the third medium is air. ### Claim 7 (depends on 1) The optical measurement apparatus according to claim 1, wherein the measurement probe is detachable to a main body unit of the optical measurement apparatus. ### Claim 8 (depends on 1) The optical measurement apparatus according to claim 1, wherein the specimen is body tissue. ### Claim 9 (depends on 1) The optical measurement apparatus according claim 1, wherein an absolute value of a difference between the refractive index of the specimen and the refractive index of the first medium is equal to or less than 0.1. ### Claim 10 (depends on 1) The optical measurement apparatus according to claim 1, wherein the first detection intensity is measured with respect to the first medium accommodated in a container provided with, on an inner surface thereof, a light absorption member that absorbs light, and the second detection intensity is measured with respect to the second medium accommodated in the container. ### Claim 11 A calibration method executed by an optical measurement apparatus that includes a measurement probe, which irradiates a specimen with illumination light and optically receives returned light of the illumination light reflected and/or scattered from the specimen, and that performs optical measurement of the specimen, the calibration method comprising the steps of: calculating a background intensity of background light to be used in correcting the returned light from the specimen, from a product of a value and a third detection intensity, the value being of a ratio of a first detection intensity to a second detection intensity, the first detection intensity being an intensity of the returned light detected when a first medium having a refractive index that is the same as that of the specimen is irradiated with the illumination light by the measurement probe and detected in a state of not including the returned light from the first medium, the second detection intensity being an intensity of the returned light detected when a second medium is irradiated with the illumination light by the measurement probe and detected in a state of not including the returned light from the second medium, and the third detection intensity being an intensity of the returned light detected when a third medium is irradiated with the illumination light by the measurement probe and detected in a state of not including the returned light from the third medium; and subtracting the background intensity from a detection intensity of the returned light from the specimen.