# US 2018/0322686 A1 · Method and Apparatus for Digitizing the Appearance of a Real Material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0322686 A1 - Document ID: US20180322686A1 - Status: Published application - Kind: A1 - Application number: 16/034,515 - Filed: 2018-07-13 - Published: 2018-11-08 - Earliest claimed: 2014-12-11 - Assignees: X-Rite Switzerland GmbH - Applicants: X-Rite Switzerland GmbH - Inventors: Adrian Kohlbrenner; Martin Rump; Beat Frick; Christopher Schwartz - Web page: https://patentgrep.com/patent/US20180322686A1 ## CPC - G06T 15/10: Geometric effects - G01N 21/57: Measuring gloss - H04N 23/56: provided with illuminating means - G06T 2200/04: involving 3D image data - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - 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 A system and method of determining data representing a mapping of optical signals described by image data of a reflecting surface of a structure to a three-dimensional surface geometry of the reflecting surface is provided. At least first, second and third light sources are provided, comprising a broadband point light source, a spectrally variable point light source and a movable linear broadband light source, respectively. First, second and third images are acquired, corresponding to each light source. Surface geometry data describing a three-dimensional surface geometry of the reflecting surface is acquired. Based on the image data and the surface geometry data, reflecting surface mapping data describing a mapping between the reflections described by the first image data, second image data and third image data, and the three-dimensional surface geometry of the reflecting surface is determined. ## Claims ### Claim at position 1 1-16. (canceled) ### Claim 17 A system for determining reflectance properties of a reflecting surface of a structure, comprising: a support part on which the structure may be mounted; at least one first light source comprising a broadband point light source oriented toward the reflecting surface; at least one second light source comprising a spectrally variable point light source oriented toward the reflecting surface; at least one third light source comprising a linear broadband light source oriented toward the reflecting surface at a plurality of angles of illumination; a fourth light source comprising a structured light source oriented toward the reflecting surface; at least one digital camera; and a computer which is operatively coupled to the at least one digital camera and configured to execute a computer program which, when running on the computer or when loaded onto the computer, causes the computer to perform the following data processing steps: acquiring first image data from the at least one digital camera corresponding to a reflection signal of the first light source from the reflecting surface; acquiring second image data from the at least one digital camera corresponding to a reflection signal of the second light source from the reflecting surface; acquiring third image data from the at least one digital camera corresponding to a reflection signal of the third light source from the reflecting surface; acquiring fourth image data from the at least one digital camera corresponding to a reflection signal of the fourth light source from the reflecting surface; determining reflecting surface mapping data describing a mapping between the reflections described by the first image data, the second image data, the third image data, and the fourth image data. ### Claim 18 (depends on 17) The system according to claim 17 further comprising a dome, wherein the at least one digital camera, the first light source, the second light source, the third light source and the fourth light source are disposed in the dome above the support part. ### Claim 19 (depends on 17) The system according to claim 17, wherein the support part comprises a turntable, and the turntable is rotatable with respect to the at least one digital camera, the first, second, third and fourth light sources. ### Claim 20 (depends on 17) The system according to claim 17, wherein the at least one digital camera comprises a plurality of digital cameras. ### Claim 21 (depends on 17) The system according to claim 17, wherein the first image data comprises a point light monochrome image, the second image data comprises a plurality of point light spectral images, and the third image data comprises a plurality of linear light monochrome images. ### Claim 22 (depends on 17) The system according to claim 17 wherein the computer is further configured to convert the fourth image data into surface geometry data describing a height field of the structure. ### Claim 23 (depends on 17) The system according to claim 17, wherein the first image data comprises at least one point light monochrome image, the second image data comprises a plurality of point light spectral images, and the third image data comprises a plurality of linear light monochrome images, and wherein the computer is configured to convert the fourth image data into surface geometry data describing a height field of the structure; and project the at least one point light monochrome image, the plurality of point light spectral images, and the plurality of linear light monochrome images onto the height field. ### Claim 24 (depends on 23) The system according to claim 23, wherein the computer is further configured to fit a model of a spatially varying bidirectional reflectance distribution function (SVBRDF) to the images projected onto the height field. ### Claim 25 (depends on 23) The system according to claim 23, wherein the computer is further configured to determine per-pixel self-shadowing parameters from the images projected onto the height field. ### Claim 26 A non-transitory computer-readable storage medium including a computer program which, when running on a computer or when loaded onto a computer, causes the computer to perform the following data processing steps: a) acquiring first image data describing an image of a reflection of a point source of broadband light from the reflecting surface; b) acquiring second image data describing a plurality of images of reflections of a point source of light from the reflecting surface at a plurality of spectral colors; c) acquiring third image data describing a plurality of images of reflections of a linear source of light from the reflecting surface at a plurality of angles of illumination; d) acquiring surface geometry data describing a three-dimensional surface geometry of the reflecting surface; and e) determining, based on the first image data and the second image and the third image data and the surface geometry data, reflecting surface mapping data describing a mapping between the reflections described by the first image data, second image data, third image data and the three-dimensional surface geometry of the reflecting surface. ### Claim 27 (depends on 26) The non-transitory computer-readable storage medium according to claim 26, wherein the first image data comprises a point light monochrome image, the second image data comprises a plurality of point light spectral images, and the third image data comprises a plurality of linear light monochrome images. ### Claim 28 (depends on 26) The non-transitory computer-readable storage medium according to claim 26, wherein the step of acquiring surface geometry data describing a three-dimensional surface geometry of the reflecting surface further comprises acquiring fourth image data describing an image of a reflection of a structured light source from the reflecting surface. ### Claim 29 (depends on 28) The non-transitory computer-readable storage medium according to claim 28, wherein the program causes the computer to perform the further step of converting the fourth image data into surface geometry data describing a height field of the structure. ### Claim 30 (depends on 26) The non-transitory computer-readable storage medium according to claim 26, wherein the first image data comprises at least one point light monochrome image, the second image data comprises a plurality of point light spectral images, the third image data comprises a plurality of linear light monochrome images, and surface geometry data describing a three-dimensional surface geometry of the reflecting surface comprises fourth image data describing an image of a reflection of a structured light source from the reflecting surface; and wherein the program causes the computer to perform the further steps of converting the fourth image data into surface geometry data describing a height field of the structure; and projecting the at least one point light monochrome image, the plurality of point light spectral images, and the plurality of linear light monochrome images onto the height field. ### Claim 31 (depends on 30) The non-transitory computer-readable storage medium according to claim 30, wherein the program causes the computer to perform the further step of fitting a model of a spatially varying bidirectional reflectance distribution function (SVBRDF) to the images projected onto the height field. ### Claim 32 (depends on 30) The non-transitory computer-readable storage medium according to claim 30, wherein the program causes the computer to perform the further step of determining per-pixel self-shadowing parameters from the images projected onto the height field.