# US 11,439,483 B2 · Intraoral scanner that compensates for non-fixed magnification > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,439,483 B2 - Document ID: US11439483B2 - Status: Granted - Kind: B2 - Application number: 17/492,453 - Filed: 2021-10-01 - Published: 2022-01-27 - Granted: 2022-09-13 - Earliest claimed: 2014-08-15 - Assignees: Align Technology, Inc. - Applicants: Align Technology, Inc. - Inventors: Tal Verker; Adi Levin; Ofer Saphier; Maayan Moshe - Web page: https://patentgrep.com/patent/US11439483B2 ## CPC - A61C 9/0066: {Depth determination through adaptive focusing} - G01B 11/24: for measuring contours or curvatures - G02B 21/006: {focusing arrangements; selection of the plane to be imaged} - G02B 23/2446: {of the image relay (G02B23/26 takes precedence)} - G02B 23/2461: {Illumination} - G02B 23/26: using light guides {(for illumination G02B23/2469)} - G02B 27/0025: {for optical correction, e.g. distorsion, aberration} - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A system comprises alight source to provide light, an optical system comprises focusing optics to focus the light onto a focal surface, a detector to measure returning light that is reflected off of a three dimensional object, a translation mechanism to displace the focal surface along an imaging axis defined by the optical path, and one or more processor. The one or more processor is to generate measurement data comprising coordinates of a plurality of surface points of the three dimensional object based on the measured returning light; adjust the coordinates of the subset of the plurality of surface points along up to three axes to correct the measurement data so as to remove inaccuracies caused by changes in magnification at the focal surface; and generate a three dimensional model of the three dimensional object using corrected measurement data. ## Claims ### Claim 1 A system for performing intraoral scans, comprising: alight source to provide light; an optical system comprising a plurality of lenses disposed along an optical path of the light, wherein the optical system comprises focusing optics to perform focusing of the light onto a focal surface and to direct the light toward a three dimensional object to be imaged in an oral cavity, the focusing optics comprising at least one lens of the plurality of lenses, wherein the optical system is a non-telecentric optical system having a non-fixed magnification; a detector to measure returning light that is reflected off of the three dimensional object and directed back through the focusing optics; a translation mechanism to adjust a position of the at least one lens to displace the focal surface along an imaging axis defined by the optical path, wherein due at least in part to the optical system being a non-telecentric optical system, adjustment of the position of the at least one lens and displacement of the focal surface along the imaging axis causes changes in a magnification at the focal surface and an accompanying inaccuracy in measurements of the three dimensional object; and one or more processor to: generate measurement data comprising coordinates of a plurality of surface points of the three dimensional object based on the measured returning light, wherein the coordinates for at least a subset of the plurality of surface points comprise inaccuracies caused by the changes in magnification at the focal surface; adjust the coordinates of the subset of the plurality of surface points along up to three axes to correct the measurement data so as to remove the inaccuracies caused by the changes in magnification at the focal surface, wherein an x coordinate, a y coordinate and a z coordinate are adjustable for each surface point of the plurality of surface points; and generate a three dimensional model of the three dimensional object using corrected measurement data in which the inaccuracies caused by the changes in magnification at the focal surface have been removed. ### Claim 2 (depends on 1) The system of claim 1, wherein changes in the magnification at the focal surface cause an accompanying distortion in the measurements of the three dimensional object, wherein adjustment to the coordinates for at least the subset of the plurality of surface points removes the distortion, and wherein the three dimensional model is an undistorted three dimensional model of the three dimensional object. ### Claim 3 (depends on 1) The system of claim 1, wherein the one or more processor is further to: determine, for each surface point of the plurality of surface points, whether to adjust one or more of the coordinates for the surface point. ### Claim 4 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, at least the x coordinate of the at least one surface point. ### Claim 5 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, at least the y coordinate of the at least one surface point. ### Claim 6 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, at least the z coordinate of the at least one surface point. ### Claim 7 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, at least the x coordinate and the y coordinate of the at least one surface point. ### Claim 8 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, the x coordinate and the z coordinate of the at least one surface point. ### Claim 9 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, at least the y coordinate and the z coordinate of the at least one surface point. ### Claim 10 (depends on 1) The system of claim 1, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, the x coordinate, the y coordinate and the z coordinate of the at least one surface point. ### Claim 11 (depends on 1) The system of claim 1, further comprising: an imaging apparatus comprising the light source, the optical system, the translation mechanism, and the detector; and a computing device that connects to the imaging apparatus, the computing device comprising at least one processor of the one or more processor. ### Claim 12 (depends on 1) The system of claim 1, wherein the optical system has an axial gain of up to 7.5. ### Claim 13 (depends on 1) The system of claim 1, wherein the coordinates of the subset of the plurality of surface points are adjusted using one or more compensation model, wherein at least one compensation model of the one or more compensation model compensates for the changes in magnification at the focal surface associated with different positions of the at least one lens. ### Claim 14 (depends on 1) The system of claim 1, wherein: the detector comprises a plurality of pixels; each pixel of the plurality of pixels captures the returning light for a corresponding surface point of the plurality of surface points of the three dimensional object; and generating the measurement data comprises: determining, for each pixel of the plurality of pixels, a position of the at least one lens for which a surface point associated with the pixel is in focus; and determining, for each pixel of the plurality of pixels, a z coordinate for the surface point that corresponds to the position of the at least one lens. ### Claim 15 A system for performing intraoral scans, comprising: alight source to provide light; an optical system comprising a plurality of lenses disposed along an optical path of the light, wherein the optical system comprises focusing optics to perform focusing of the light onto a focal surface and to direct the light toward a three dimensional object to be imaged in an oral cavity, the focusing optics comprising at least one lens of the plurality of lenses, wherein the optical system is a non-telecentric optical system having a non-fixed magnification; a detector to measure returning light that is reflected off of the three dimensional object and directed back through the focusing optics; a translation mechanism to adjust a position of the at least one lens to displace the focal surface along an imaging axis defined by the optical path, wherein due at least in part to the optical system being a non-telecentric optical system, adjustment of the position of the at least one lens and displacement of the focal surface along the imaging axis causes changes in a magnification at the focal surface and an accompanying inaccuracy in measurements of the three dimensional object; and one or more processor to: generate measurement data comprising coordinates of a plurality of surface points of the three dimensional object based on the measured returning light, the coordinates for each surface point of the plurality of surface points comprising an x coordinate, a y coordinate and a z coordinate, wherein the coordinates for at least a subset of the plurality of surface points comprise inaccuracies caused by the changes in magnification at the focal surface; adjust the x coordinate and the y coordinate of one or more surface points from the subset of the plurality of surface points to correct the measurement data so as to remove the inaccuracies caused by the changes in magnification at the focal surface; and generate a three dimensional representation of the three dimensional object using corrected measurement data in which the inaccuracies caused by the changes in magnification at the focal surface have been removed. ### Claim 16 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust the z coordinate for one or more of the plurality of surface points. ### Claim 17 (depends on 15) The system of claim 15, wherein changes in the magnification at the focal surface cause an accompanying distortion in the measurements of the three dimensional object, wherein adjustment to the coordinates for at least the subset of the plurality of surface points removes the distortion, and wherein the three dimensional representation is an undistorted three dimensional model of the three dimensional object. ### Claim 18 (depends on 15) The system of claim 15, wherein the one or more processor is further to: determine, for each surface point of the plurality of surface points, whether to adjust one or more of the coordinates for the surface point. ### Claim 19 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, only the x coordinate of the at least one surface point. ### Claim 20 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, only the y coordinate of the at least one surface point. ### Claim 21 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust, for at least one surface point of the plurality of surface points, only the z coordinate of the at least one surface point. ### Claim 22 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, only the x coordinate and the z coordinate of the at least one surface point. ### Claim 23 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, only the y coordinate and the z coordinate of the at least one surface point. ### Claim 24 (depends on 15) The system of claim 15, wherein the one or more processor is further to: adjust, for at least one surface point from the subset of the plurality of surface points, the x coordinate, the y coordinate and the z coordinate of the at least one surface point. ### Claim 25 (depends on 15) The system of claim 15, further comprising: an imaging apparatus comprising the light source, the optical system, the translation mechanism, and the detector; and a computing device that connects to the imaging apparatus, the computing device comprising at least one processor of the one or more processor. ### Claim 26 (depends on 15) The system of claim 15, wherein the optical system has an axial gain of up to 7.5. ### Claim 27 (depends on 15) The system of claim 15, wherein the coordinates of the subset of the plurality of surface points are adjusted using one or more compensation model, wherein at least one compensation model of the one or more compensation model compensates for the changes in magnification at the focal surface associated with different positions of the at least one lens. ### Claim 28 (depends on 15) The system of claim 15, wherein: the detector comprises a plurality of pixels; each pixel of the plurality of pixels captures the returning light for a corresponding surface point of the plurality of surface points of the three dimensional object; and generating the measurement data comprises: determining, for each pixel of the plurality of pixels, a position of the at least one lens for which a surface point associated with the pixel is in focus; and determining, for each pixel of the plurality of pixels, a z coordinate for the surface point that corresponds to the position of the at least one lens.