Intraoral scanner with dental diagnostics capabilities

• US 10,123,706 B2
• Filed: 07/27/2017
• Issued: 11/13/2018
• Est. Priority Date: 07/27/2016
• Status: Active Grant

• Current Assignee: Align Technology Incorporated
• Original Assignee: Align Technology Incorporated
• Inventors: Elbaz, Gilad, Lampert, Erez, Atiya, Yossef, Kopelman, Avi, Saphier, Ofer, Moshe, Maayan, Ayal, Shai
• Primary Examiner(s): Thompson, James A
• Application Number:
  US15/662,234
• Publication Number:
  US 20180028063A1
• Time in Patent Office: 474 Days
• Field of Search: None
• CPC Class Codes: A61B 1/24 for the mouth, i.e. stomatoscopes, e.g. with tongue depressors tongue depressors per se A61B13/00; Instruments for opening or keeping open the mouth combined with saliva removers A61C17/00; mouth openers for animals A61D15/00
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0086 using infrared radiation
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7435 Displaying user selection data, e.g. icons in a graphical user interface
• CPC Class Codes: A61C 1/088 Illuminating devices or attachments for examination of the mouth A61B1/24 and A61B1/06
• CPC Class Codes: A61C 9/0053 Optical means or methods, e.g. scanning the teeth by a laser or light beam
• CPC Class Codes: G06F 16/9535 Search customisation based on user profiles and personalisation
• CPC Class Codes: G06Q 50/01 Social networking
• CPC Class Codes: G06T 15/08 Volume rendering
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 2207/30036 Dental; Teeth
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 2210/41 Medical
• CPC Class Codes: G06T 7/55 from multiple images
• CPC Class Codes: G06T 7/75 involving models
• CPC Class Codes: H04N 13/221 using the relative movement between cameras and objects
• CPC Class Codes: H04N 13/246 Calibration of cameras
• CPC Class Codes: H04N 13/254 : in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 13/257 : Colour aspects
• CPC Class Codes: H04N 13/271 : wherein the generated image signals comprise depth maps or disparity maps

Abstract

Methods and apparatuses for generating a model of a subject'"'"'s teeth. Described herein are intraoral scanning methods and apparatuses for generating a three-dimensional model of a subject'"'"'s intraoral region (e.g., teeth) including both surface features and internal features. These methods and apparatuses may be used for identifying and evaluating lesions, caries and cracks in the teeth. Any of these methods and apparatuses may use minimum scattering coefficients and/or segmentation to form a volumetric model of the teeth.

Claims

1. A method for generating a three-dimensional (3D) volumetric model of a subject'"'"'s teeth using an intraoral scanner, the method comprising:

taking surface images of the subject'"'"'s teeth and forming a 3D surface model of at least a portion of the subject'"'"'s teeth using the intraoral scanner as the intraoral scanner is moved over the teeth;

taking a plurality of images into the teeth using a near-infrared (near-IR) wavelength with the intraoral scanner as the intraoral scanner is moved over the teeth, so that multiple images of a same internal region of the teeth are imaged, wherein taking the plurality of images into the teeth comprises emitting a near-IR light from the intraoral scanner in a first polarization, and detecting, in an image sensor in the intraoral scanner, the near-IR light returning to the intraoral scanner, wherein the near-IR light returning to the intraoral scanner is filtered to remove specular reflection by filtering near-IR light in the first polarization from the near-IR light returning to the intraoral scanner before it reaches the image sensor;

constructing grid points for an inner volume of the 3D surface model;

determining, for each of the plurality of images into the teeth, a position of the intraoral scanner relative to the subject'"'"'s teeth using the 3D surface model data;

using the position of the intraoral scanner to project the grid points on each of the plurality of images into the teeth;

determine a minimum scattering coefficient for the projected grid points from all of the plurality of images into the teeth; and

forming the 3D volumetric model of the subject'"'"'s teeth including internal features using the minimum scattering coefficient for the projected grid points.

2. The method of claim 1, wherein the near-IR light returning to the intraoral scanner is filtered to remove specular reflection by filtering all or nearly all of the near-IR light in the first polarization from the near-IR light returning to the intraoral scanner before it reaches the image sensor.

3. The method of claim 1, wherein forming the 3D surface model comprises determining a 3D surface topology using confocal focusing.

4. The method of claim 1, wherein forming the 3D surface model comprises using structured light triangulation.

5. The method of claim 1, wherein forming the 3D surface model comprises capturing a model of the teeth and gums.

6. The method of claim 1, further comprising capturing a 3D color model of the teeth as the intraoral scanner is moved over the teeth.

7. The method of claim 1, further comprising switching between capturing 3D surface model data and taking the plurality of images into the teeth as the intraoral scanner is moved over the teeth.

8. The method of claim 1, wherein taking the plurality of images comprises using a same sensor on the intraoral scanner to capture the 3D surface model data and the plurality of images into the teeth.

9. The method of claim 1, wherein taking the plurality of images into the teeth comprises small-angle penetrative images.

10. The method of claim 1, wherein taking the plurality of images into the teeth comprises using a different sensor on the intraoral scanner to capture 3D surface model data and the plurality of images into the teeth.

11. The method of claim 1, wherein forming the 3D volumetric model of the subject'"'"'s teeth comprises combing the 3D surface model data with a 3D model of the internal structure.

12. A method for generating a three-dimensional (3D) volumetric model of a subject'"'"'s teeth using an intraoral scanner, the method comprising:

taking surface images of the subject'"'"'s teeth and forming a 3D surface model of at least a portion of the subject'"'"'s teeth using the intraoral scanner as the intraoral scanner is moved over the teeth;

taking a plurality of images into the teeth using a near-infrared (near-IR) wavelength as the intraoral scanner is moved over the teeth by emitting a near-IR light from the intraoral scanner in a first polarization, and detecting, in an image sensor in the intraoral scanner, the near-IR light returning to the intraoral scanner, wherein the near-IR light returning to the intraoral scanner is filtered to remove specular reflection by filtering near-IR light in the first polarization from the near-IR light returning to the intraoral scanner before it reaches the image sensor;

constructing grid points for an inner volume of the 3D surface model;

determining, for each of the plurality of images into the teeth, a position of the intraoral scanner relative to the subject'"'"'s teeth when each of the plurality of images is captured, using the 3D surface model data;

using the position of the intraoral scanner to project the grid points on each of the plurality of images into the teeth;

determine a minimum scattering coefficient for the projected grid points from all of the plurality of images into the teeth; and

forming the 3D volumetric model of the subject'"'"'s teeth including internal features using the minimum scattering coefficient for the projected grid points.

13. An intraoral scanning system for generating a three-dimensional (3D) volumetric model of a subject'"'"'s teeth, the system comprising:

a hand-held wand having at least one image sensor and a plurality of light sources, wherein the light sources are configured to emit light at a first spectral range and a second spectral range, wherein the second spectral range is within near-infrared (near-IR) range of wavelengths;

a filter in front of the image sensor configured to filter light in the second spectral range and a first polarization; and

one or more processors operably connected to the hand-held wand, the one or more processors configured to;

take surface images of the subject'"'"'s teeth and forming a 3D surface model of at least a portion of the subject'"'"'s teeth as the intraoral scanner is moved over the teeth;

take a plurality of images into the teeth using light in the second spectral range as the intraoral scanner is moved over the teeth by emitting a near-IR light from the intraoral scanner in the first polarization, and detecting, in the at least one image sensor in the intraoral scanner, the near-IR light returning to the intraoral scanner, wherein the near-IR light returning to the intraoral scanner is filtered to remove specular reflection by filtering near-IR light in the first polarization from the near-IR light returning to the intraoral scanner before it reaches the image sensor;

construct grid points for an inner volume of the 3D surface model;

determine, for each of the plurality of images into the teeth, a position of the hand-held wand relative to the subject'"'"'s teeth using the 3D surface model data;

use the position of the intraoral scanner to project the grid points on each of the plurality of images into the teeth;

determine a minimum scattering coefficient for the projected grid points from all of the plurality of images into the teeth; and

form the 3D volumetric model of the subject'"'"'s teeth including internal features using the minimum scattering coefficient for the projected grid points.

14. The system of claim 13, wherein the hand-held wand comprises at least one additional secondary image sensor in addition to the image sensors.

15. The system of claim 13, wherein the one or more processors is configured to determine surface information by using confocal focusing.

16. The system of claim 13, wherein the one or more processors is configured to determine surface information by using confocal scanning, stereo vision or structured light triangulation.

17. The system of claim 13, wherein the hand-held wand is configured to cycle between emitting light at the first spectral range to perform a surface scan and the second spectral range to detect internal structures by switching between the first spectral range and the second spectral range so that images taken with the second spectral range share a coordinate system with the surface scan.

18. The system of claim 13, wherein the image sensor is configured to capture both the 3D surface model data and the internal data of the tooth.

19. The system of claim 13, wherein the plurality of light sources comprises a white light source.

20. The system of claim 13, further wherein the plurality of light sources and the image sensor are arranged so that light emitted in the second spectral range is reflected from a tooth and received by the one or more sensors at an angle of between 0°

and 15°

.