# US 11,307,094 B2 · System and method for hyperspectral imaging in highly scattering media by the spectral phasor approach using two filters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,094 B2 - Document ID: US11307094B2 - Status: Granted - Kind: B2 - Application number: 16/886,092 - Filed: 2020-05-28 - Published: 2020-12-03 - Granted: 2022-04-19 - Earliest claimed: 2019-05-28 - Assignees: The Regents of the University of California - Applicants: The Regents of the University of California - Inventors: Enrico Gratton; Alexander Dvornikov - Web page: https://patentgrep.com/patent/US11307094B2 ## CPC - G01J 3/2823: {Imaging spectrometer} - G01N 21/6458: {Fluorescence microscopy (fluorescence microscopes per se G02B21/0076 and G02B21/16)} - G01J 3/0202: {Mechanical elements; Supports for optical elements} - G01J 3/2803: {using photoelectric array detector} - G01J 3/4406: {Fluorescence spectrometry} - G01N 21/64: Fluorescence; Phosphorescence - H04N 23/72: Combination of two or more compensation controls - H04N 25/13: characterised by the spectral characteristics of the filter elements - G01J 2003/1213: {Filters in general, e.g. dichroic, band} - G01J 2003/1221: {Mounting; Adjustment} - G01J 2003/2826: {Multispectral imaging, e.g. filter imaging} - G01N 21/4795: {spatially resolved investigating of object in scattering medium (in vivo A61B)} - G01N 21/6408: {with measurement of decay time, time resolved fluorescence} - G01N 2021/6421: {Measuring at two or more wavelengths} - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An imaging system comprises an excitation light source, a directing element positioned to direct light from the excitation light source toward a sample, a detector configured to measure incoming light from the sample, a filter cavity positioned between the sample and the detector, a first filter configured to be inserted into the filter cavity, a sine filter configured to be inserted into the filter cavity, and a processing unit communicatively connected to the detector, configured to receive image data from the detector to form an image. Methods of constructing a hyperspectral image of a sample are also described. ## Claims ### Claim 1 An imaging system comprising: an excitation light source; a directing element positioned to direct light from the excitation light source toward a sample; a detector configured to measure incoming light from the sample; a filter cavity positioned between the sample and the detector; a first filter configured to be inserted into the filter cavity; a second filter configured to be inserted into the filter cavity; and a processing unit communicatively connected to the detector, configured to receive image data from the detector to form an image; wherein the first filter is a linearly increasing transmission filter and the second filter is a linearly decreasing transmission filter. ### Claim 2 (depends on 1) The system of claim 1, wherein the excitation light source is selected from the group consisting of: a Ti:Sa laser, a white laser, a widely tunable laser, a fiber laser, a tungsten lamp, and a white LED. ### Claim 3 (depends on 1) The system of claim 1, further comprising a light permeable media positioned between the sample and the filter cavity. ### Claim 4 (depends on 1) The system of claim 1, wherein the first filter is a plastic cyan transmission filter. ### Claim 5 (depends on 1) The system of claim 1, wherein the second filter is a plastic green transmission filter. ### Claim 6 (depends on 1) The system of claim 1, wherein the first filter and the second filter are provided on a rotating filter wheel having a filter space that is empty or has a transparent filter. ### Claim 7 (depends on 1) The system of claim 1, wherein the first filter and the second-filter are provided on a filter slide having a filter space that is empty or has a transparent filter. ### Claim 8 (depends on 1) The system of claim 1, comprising three detectors, wherein a first detector is coupled to the first filter, a second detector is coupled to the second filter, and a third detector is coupled to a transparent filter or to no filter. ### Claim 9 (depends on 1) The system of claim 1, wherein the detector has three detecting regions, a first region coupled to the first filter, a second region coupled to the second filter, and a third region coupled to a transparent filter or to no filter. ### Claim 10 (depends on 1) The system of claim 1, wherein the imaging system is incorporated into a camera having the first filter, the second filter, and a transparent filter applied to separate regions of the detector. ### Claim 11 (depends on 1) The system of claim 1, further comprising a group velocity dispersion (GVD) compensator. ### Claim 12 (depends on 1) The system of claim 1, further comprising an acoustic-optic modulator. ### Claim 13 (depends on 1) The system of claim 1, further comprising an x-y galvanometric scanner. ### Claim 14 An imaging system comprising: an excitation light source; a directing element positioned to direct light from the excitation light source toward a sample; a detector configured to measure incoming light from the sample; a filter cavity positioned between the sample and the detector; a first filter configured to be inserted into the filter cavity; a second filter configured to be inserted into the filter cavity; a processing unit communicatively connected to the detector, configured to receive image data from the detector to form an image; and a non-transitory computer-readable memory with instructions stored thereon, which when executed by the processing unit, construct a hyperspectral image of a sample, the instructions comprising the steps of: recording a light intensity as F1(λ) over a wavelength range while the first filter is positioned between the sample and the detector; recording a light intensity as F2(λ) over the wavelength range while the second filter is positioned between the sample and the detector; recording a total intensity as I(λ) over the wavelength range with no filter or a transparent filter positioned between the sample and the detector; calculating a normalized transmission of the first filter; calculating a normalized total intensity of transmission through the first filter; calculating a spectral phasor coordinate of the normalized total intensity through the first filter; calculating the normalized transmission of the second filter; calculating the normalized total intensity of transmission through the second filter; calculating the spectral phasor coordinate of the normalized total intensity through the second filter; and generating a hyperspectral image of the sample based on the calculated spectral phasor coordinates. ### Claim 15 (depends on 14) The system of claim 14, wherein the first filter is a cosine filter and the second filter is a sine filter. ### Claim 16 A method of constructing a hyperspectral image of a sample, comprising the steps of: passing an excitation light source through a sample and through a first filter and recording, with a detector, a light intensity as F1(λ) over a wavelength range; passing the excitation light source through the sample and through a second filter and recording, with the detector, a light intensity as F2(λ) over the wavelength range; passing the excitation light source through the sample unfiltered and recording, with the detector, a total intensity as I(λ) over the wavelength range; calculating a normalized transmission of the first filter; calculating a normalized total intensity of transmission through the first filter; calculating a spectral phasor coordinate of the normalized total intensity through the first filter; calculating a normalized transmission of the second filter; calculating a normalized total intensity of transmission through the second filter; calculating a spectral phasor coordinate of the normalized total intensity through the second filter; and generating a hyperspectral image of the sample based on the calculated spectral phasor coordinates. ### Claim 17 (depends on 16) The method of claim 16, wherein the wavelength range is between 400 nm and 1000 nm. ### Claim 18 (depends on 16) The method of claim 16, further comprising the steps of: applying a first correction factor to the phase and amplitude of the normalized total intensity of transmission through the first filter; and applying a second correction factor to the phase and amplitude of the normalized total intensity of transmission through the second filter. ### Claim 19 A method of constructing a hyperspectral image of a sample, comprising the steps of: passing an excitation light source through a sample and through a filter with linearly increasing transmission and recording, with a detector, a light intensity as Fincrease(λ) over a wavelength range; passing the excitation light source through the sample and through a filter with linearly decreasing transmission and recording, with the detector, a light intensity as Fdecrease(λ) over the wavelength range; calculating the channel ratio using a general polarization formula; and generating a hyperspectral image of the sample based on the calculated channel ratio.