# US 2019/0170507 A1 · Hybrid 3d optical scanning system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170507 A1 - Document ID: US20190170507A1 - Status: Published application - Kind: A1 - Application number: 16/350,844 - Filed: 2017-07-27 - Published: 2019-06-06 - Earliest claimed: 2016-07-27 - Assignees: Scanmen, Ltd.; Vehicle Hail Scan Systems, LLC - Applicants: Scanmen, Ltd.; Vehicle Hail Scan Systems, LLC - Inventors: AIVARAS ALFONSAS GRAUZINIS; GEERT WILLEMS - Web page: https://patentgrep.com/patent/US20190170507A1 ## CPC - G01B 11/2513: {with several lines being projected in more than one direction, e.g. grids, patterns} - G01B 11/2518: {Projection by scanning of the object} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A hybrid 3D optical scanning system combining methodologies of active stereo 3D reconstruction and deflectometry to provide accurate 3D surface measurements of an object under inspection. In a preferred embodiment, the present system comprises a calibrated digital camera stereo pair and first digital projector for active stereo 3D reconstruction metrology positioned at selected distance apart on the same horizontal plane facing the inspection object at an optimal incidence angle relative to the object surface. A secondary digital projector for deflectometry is directed to project a pattern sequence across the optical projection path of the first digital projector and onto a nonplanar deflection screen extended between the digital camera and the inspection object at a selected angle relative thereto, the selected angle being chosen so that that the pattern projected onto the deflection screen by the secondary digital projector reflects from the surface of the inspection object towards the digital camera. Calibrated active stereo 3D reconstruction is used to derive global shape and the uncalibrated nonplanar deflected light acquires curvature of local fine deformations and surface imperfections along the object surface. The calibrated camera allows per pixel correlations to be defined between the separate acquisition methods and produces accurate absolute measurements of both shape and local features of specular, glossy, metallic curved surfaces. ## Claims ### Claim 1 A hybrid optical scanning system using active stereo 3D reconstruction and deflectometry techniques for acquiring three-dimensional measurements of an object surface under inspection, comprising: a first digital projector for projecting a sequence of multi-scale random patterns along a first optical path directed upon the object surface at a predetermined incident angle; a second digital projector for projecting a sequence of non-calibrated light patterns along a second optical path apart from the first optical path for deflection onto the object surface; a nonplanar deflection screen disposed at an angle incident to the object surface and positioned in the second optical path to deflect the sequence of non-calibrated light patterns from said second digital projector onto the object surface; and digital camera stereo pair means disposed facing the object surface in a direction substantially parallel to the first optical path and calibrated for capturing reflected images of the multi-scale random patterns projected on the object surface further combined with the sequence of deflected non-calibrated light patterns projected thereon. ### Claim 2 (depends on 1) A hybrid optical scanning system according to claim 1, further comprising: computer means coupled to said digital camera stereo pair means for processing the captured images using image processing algorithms to provide a three-dimensional reconstruction of the object surface from the captured images of the sequence of patterns projected thereon including measurements of dents, deformations and scratches. ### Claim 3 (depends on 1) A hybrid optical scanning system according to claim 1, wherein: said second digital projector is positioned forwardly facing said nonplanar deflection screen so that the non-calibrated light patterns may be reflected onto the object surface. ### Claim 4 (depends on 1) A hybrid optical scanning system according to claim 1, wherein: said second digital projector is positioned rearwardly facing said nonplanar deflection screen so that the non-calibrated light patterns may be projected therethrough and onto the object surface. ### Claim 5 (depends on 4) A hybrid optical scanning system according to claim 4, wherein: said digital camera stereo pair means comprises a plurality of active stereo 3D camera pairs each arranged to face the object surface from different respective directions; and more than one second digital projectors are configured to illuminate said nonplanar deflection screen from separate directions; whereby the respective active stereo 3D camera pairs are arranged so that the optical pass of each camera pair is made to overlap sufficiently to reconstruct and measure expanded areas of the object surface with said active stereo 3D camera pairs being calibrated using a multi-scale calibration pattern or a multi-scale random pattern. ### Claim 6 (depends on 1) A hybrid optical scanning system according to claim 1, further comprising: a nonplanar optical path folding mirror positioned along the second optical path for redirecting the non-calibrated light patterns from said second digital projector onto the nonplanar deflection screen to rectify and optimize the nonplanar deflections onto the object surface. ### Claim 7 (depends on 2) A hybrid optical scanning system according to claim 2, wherein: the sequence of multi-scale random patterns projected onto the object surface from the first digital projector include gray code patterns, sinusoidal fringe patterns, or a combination thereof; and the sequence of non-calibrated light patterns projected from the second digital projector onto the object surface via deflection reflectometry include stripe or fringe pattern sequences. ### Claim 8 (depends on 7) A hybrid optical scanning system according to claim 7, wherein a combination of low and high frequency multi-directional patterns of non-calibrated light are projected onto the object surface via the nonplanar deflection screen to detect and measure dents and deformations and linear scratches and abrasions on the object surface. ### Claim 9 A hybrid optical scanning system using active stereo 3D reconstruction and deflectometry techniques for acquiring three-dimensional measurements of an object surface under inspection, comprising: a digital projector for projecting a sequence of multi-scale random patterns along a direct optical path projected upon the object surface at a predetermined incident angle; light path deflector means disposed for selectively redirecting the sequence of multi-scale random patterns from the direct optical path and along a deflection path; a nonplanar deflection screen disposed at an angle incident to the object surface to receive redirected multi-scale random patterns along the deflection path and providing further deflection thereof onto the object surface; and digital camera stereo pair means disposed facing the object surface in a direction substantially parallel to the direct optical path of said digital projector and calibrated therewith for capturing reflected images of the sequence of multi-scale random patterns projected directly onto the object surface combined with the redirected patterns deflected thereon. ### Claim 10 (depends on 9) A hybrid optical scanning system according to claim 9, further comprising: computer means coupled to said digital camera stereo pair means for processing the captured images using image processing algorithms to provide a three-dimensional reconstruction of the object surface from the captured images of the sequence of multi-scale random patterns projected and deflected thereon including measurements of dents, deformations and scratches. ### Claim 11 (depends on 10) A hybrid optical scanning system according to claim 10, wherein said light path deflector means comprises: a curved optical path-splitting mirror disposed in a stationary position along the direct path of projection. ### Claim 12 (depends on 10) A hybrid optical scanning system according to claim 10, wherein said light path deflector means comprises: an active mirror pivotally disposed for rotation into and out of the direct path of projection. ### Claim 13 An optical scanning method combining active stereo 3D reconstruction and deflectometry system techniques to acquire three-dimensional measurements of an object surface under inspection, comprising the steps of: projecting multi-scale random patterns along a direct optical path projected upon the object surface at a predetermined incident angle; projecting a sequence of non-calibrated light patterns along a second optical path apart from the first optical path for deflection onto the object surface; and capturing reflected images of the multi-scale random patterns projected on the object surface further combined with the sequence of deflected non-calibrated light patterns projected thereon. ### Claim 14 (depends on 13) An optical scanning method according to claim 13, further comprising the steps of: image processing of the captured images of patterns reflected from the object surface to derive the global shape of the object surface; and further processing of the captured images of the deflected light patterns to generate a phase map of the object surface wherein steep changes of phase in relation to surrounding pixels indicative of surface deformations are marked and projected onto a depth map for indexing and measurement in absolute scale.