# US 10,768,497 B2 · Hyperspectral imaging system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,497 B2 - Document ID: US10768497B2 - Status: Granted - Kind: B2 - Application number: 15/283,765 - Filed: 2016-10-03 - Published: 2018-04-05 - Granted: 2020-09-08 - Earliest claimed: 2016-10-03 - Assignees: Xerox Corporation - Applicants: Xerox Corporation - Inventors: Robert P. Herloski - Web page: https://patentgrep.com/patent/US10768497B2 ## CPC - G02F 1/137: characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering - G03G 15/5041: {Detecting a toner image, e.g. density, toner coverage, using a test patch (G03G15/553 takes precedence)} - G03G 15/5062: {by measuring the characteristics of an image on the copy material} - H04N 1/6044: {involving a sensor integrated in the machine or otherwise specifically adapted to read the test pattern} - G02F 2202/022: polymeric - G02F 2203/12: spatial light modulator - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A hyperspectral imaging system, comprising an input polarizer arranged to receive and polarize a first light, a liquid crystal variable retarder to change a polarization of the first light in a wavelength-dependent manner, an output polarizer arranged to receive the wavelength-dependent polarized first light, a voltage source electrically connected to the liquid crystal variable retarder, a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the first light. A linear image sensor has a length extending in a direction to obtain images of the first light, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the first light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor. ## Claims ### Claim 1 A hyperspectral imaging system, comprising: a first light source outputting first light configured to illuminate an image bearing surface; an input polarizer disposed within a device housing including an aperture arranged to receive and polarize the first light illuminating the image bearing surface and received via the aperture; a liquid crystal variable retarder disposed within the device housing and arranged after the input polarizer along a path of the first light to change a polarization of the first light in a wavelength-dependent manner; an output polarizer disposed within the device housing and arranged to receive the wavelength-dependent polarized first light and to convert polarization state information of the first light into a form detectable as light intensity; a voltage source electrically connected to the liquid crystal variable retarder; a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the first light; a linear image sensor disposed within the device housing and having a length extending in a direction to obtain images of the first light, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the first light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor; and an internal light source disposed within the device housing, which internal light source is separate and distinct from the first light source, arranged to output second light emitted from within the housing and directly towards the input polarizer and the linear image sensor such that second light emitted by the internal light source from within the housing is received by the linear image sensor. ### Claim 2 (depends on 1) The system of claim 1, wherein the linear sensor is a one-dimensional, sensor array. ### Claim 3 (depends on 1) The system of claim 1, wherein the linear sensor is a two-dimensional, sensor array having pixels binned together to form the linear sensor. ### Claim 4 (depends on 1) The system of claim 1, wherein the linear image sensor is a full width array sensor. ### Claim 5 (depends on 1) The system of claim 1, wherein the portion of the linear sensor corresponds to a single pixel. ### Claim 6 (depends on 1) The system of claim 1, wherein the portion of the linear sensor corresponds to a plurality of pixels binned together. ### Claim 7 (depends on 1) The system of claim 1, further comprising a processor programmed to perform a transform of the output signal to generate spectral information. ### Claim 8 (depends on 7) The system of claim 7, wherein the transform is a Fourier transform. ### Claim 9 A printer, comprising: I.) a first light source; II.) an image bearing surface positioned to receive light from the first light source and to form output light from the light incident thereon, the image bearing surface disposed on a drum or a belt to move the image bearing surface in a process direction; III.) a hyperspectral imaging system comprising: an input polarizer disposed within a device housing including an aperture arranged to receive and polarize the output light received via the aperture; a liquid crystal variable retarder disposed within the device housing and arranged after the input polarizer along a path of the output light to change polarization of the output light in a wavelength-dependent manner; an output polarizer disposed within the device housing and arranged to receive the wavelength-dependent polarized output light and to convert polarization state information of the output light into a form detectable as light intensity; a voltage source electrically connected to the liquid crystal variable retarder; a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the output light; a linear image sensor disposed within the device housing and having a length extending in a direction to obtain images of the output light in a cross-process direction, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the output light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor; an internal light source disposed within the device housing, which internal light source is separate and distinct from the first light source, arranged to output internal light emitted from within the housing to directly illuminate the input polarizer and the linear image sensor such that internal light emitted by the internal light source from within the housing is received by the linear image sensor; and IV.) a processor to perform transformations of the output signal into spectral information. ### Claim 10 (depends on 9) The printer of claim 9, wherein the linear sensor is a one-dimensional, sensor array. ### Claim 11 (depends on 9) The printer of claim 9, wherein the linear sensor is a two-dimensional, sensor array having pixels binned together to form the linear sensor. ### Claim 12 (depends on 9) The printer of claim 9, wherein the linear image sensor is a full width array sensor. ### Claim 13 (depends on 9) The printer of claim 9, wherein the image bearing surface is a photoreceptor. ### Claim 14 (depends on 9) The printer of claim 9, wherein the portion of the linear sensor corresponds to a single pixel. ### Claim 15 (depends on 9) The printer of claim 9, wherein the portion of the linear sensor corresponds to a plurality of pixels extending along the cross-process direction, the plurality of pixels being binned together. ### Claim 16 (depends on 9) The printer of claim 9, wherein the transform is a Fourier transform. ### Claim 17 (depends on 9) The printer of claim 9, wherein the image bearing surface is an output sheet of paper. ### Claim 18 (depends on 9) The printer of claim 9, wherein the image bearing surface is a photoreceptor belt. ### Claim 19 (depends on 1) The system of claim 1 further comprising: a photodetector, which photodetector is separate and distinct from the linear image sensor, arranged to obtain first light illuminating the image bearing surface and received via the aperture. ### Claim 20 (depends on 9) The printer of claim 9 further comprising: a photodetector, which photodetector is separate and distinct from the linear image sensor, arranged to obtain output light received via the aperture. ### Claim 21 (depends on 19) The system of claim 19, wherein the photodetector is arranged to obtain second light emitted by the internal light source. ### Claim 22 (depends on 20) The printer of claim 20, wherein the photodetector is arranged to obtain internal light emitted by the internal light source.