Intraoral 3D scanner employing multiple miniature cameras and multiple miniature pattern projectors

Patent metadata

Field	Value
Publication number	US-11563929-B2
Application number	US-202016910042-A
Country	US
Kind code	B2
Filing date	Jun 23, 2020
Priority date	Jun 24, 2019
Publication date	Jan 24, 2023
Grant date	Jan 24, 2023

Abstract

A method for generating a 3D image includes driving structured light projector(s) to project a pattern of light on an intraoral 3D surface, and driving camera(s) to capture images, each image including at least a portion of the projected pattern, each one of the camera(s) comprising an array of pixels. A processor compares a series of images captured by each camera and determines which of the portions of the projected pattern can be tracked across the images. The processor constructs a three-dimensional model of the intraoral three-dimensional surface based at least in part on the comparison of the series of images. Other embodiments are also described.

First claim

What is claimed is:

1. An intraoral scanning system, comprising:
an intraoral scanner comprising one or more cameras and one or more structured light projectors, the intraoral scanner to generate a series of images using the one or more cameras, each image including at least a portion of a pattern projected by the one or more structured light projectors onto an intraoral three-dimensional surface; and
a processor to:
compare the series of images captured by the one or more cameras;
determine which of the portions of the projected pattern can be tracked across the series of images based on the comparison of the series of images;
solve a correspondence algorithm for the tracked portions of the projected pattern in at least one of the series of images; and
construct a three-dimensional model of the intraoral three-dimensional surface based at least in part on the comparison of the series of images, wherein a solution to the correspondence algorithm is used to construct the three-dimensional model.

2. The intraoral scanning system according to claim 1 , wherein the processor is further to:
use the solved correspondence algorithm for the tracked portions in the at least one of the series of images to solve the correspondence algorithm for the tracked portions of the projected pattern in at least another image of the series of images.

3. The intraoral scanning system according to claim 1 , wherein the processor is further to:
solve the correspondence algorithm for the tracked portions of the projected pattern based on positions of the tracked portions in each image throughout the series of images.

4. The intraoral scanning system according to claim 1 , wherein the pattern is spatially fixed relative to the one or more cameras.

5. The intraoral scanning system according to claim 1 , wherein the projected pattern comprises a plurality of projected spots of light, and wherein the portion of the projected pattern corresponds to a projected spot s of the plurality of projected spots of light.

6. The intraoral scanning system according to claim 1 , wherein the correspondence algorithm uses, at least in-part, the portions of the projected pattern that are determined to be trackable across the series of images.

7. The intraoral scanning system of claim 1 , wherein the processor is a component of the intraoral scanner.

8. An intraoral scanning system, comprising:
an intraoral scanner comprising one or more cameras and one or more structured light projectors, the intraoral scanner to generate a series of images using the one or more cameras, each image including at least a portion of a pattern projected by the one or more structured light projectors onto an intraoral three-dimensional surface, wherein the projected pattern comprises a plurality of projected spots of light, and wherein the portion of the projected pattern corresponds to a projected spot s of the plurality of projected spots of light; and
a processor to:
compare the series of images captured by the one or more cameras based on stored calibration values indicating (a) a camera ray corresponding to each pixel on a camera sensor of each one of the one or more cameras, and (b) a projector ray corresponding to each one of the projected spots of light from each one of the one or more structured light projectors, wherein each projector ray corresponds to a respective path of pixels on at least one of the camera sensors, wherein determining which portions of the projected pattern can be tracked comprises determining which of the projected spots s can be tracked across the series of images, and wherein each tracked spot s moves along a path of pixels corresponding to a respective projector ray r.

9. The intraoral scanning system according to claim 8 , wherein the processor is further to:
determine, for each tracked spot s, a plurality of possible paths p of pixels on a given one of the cameras, paths p corresponding to a respective plurality of possible projector rays r.

10. The intraoral scanning system according to claim 9 , wherein the processor is further to run a correspondence algorithm to:
for each of the possible projector rays r:
identify how many other cameras, on their respective paths p 1 of pixels corresponding to projector ray r, detected respective spots q corresponding to respective camera rays that intersect projector ray r and the camera ray of the given one of the cameras corresponding to the tracked spot s;
identify a given projector ray r 1 for which the highest number of other cameras detected respective spots q; and
identify projector ray r 1 as the particular projector ray r that produced the tracked spot s.

11. The intraoral scanning system according to claim 8 , wherein the processor is further to:
run a correspondence algorithm to compute respective three-dimensional positions of a plurality of detected spots on the intraoral three-dimensional surface, as captured in the series of images; and
in at least one of the series of images, identify a detected spot as being from a particular projector ray r by identifying the detected spot as being a tracked spot s moving along the path of pixels corresponding to the particular projector ray r.

12. The intraoral scanning system according to claim 8 , wherein the processor is further to:
run a correspondence algorithm to compute respective three-dimensional positions of a plurality of detected spots on the intraoral three-dimensional surface, as captured in the series of images, and
remove from being considered as a point on the intraoral three-dimensional surface a spot that (i) is identified as being from particular projector ray r based on the three-dimensional position computed by the correspondence algorithm, and (ii) is not identified as being a tracked spot s moving along the path of pixels corresponding to particular projector ray r.

13. The intraoral scanning system according to claim 8 , wherein the processor is further to:
run a correspondence algorithm to compute respective three-dimensional positions of a plurality of detected spots on the intraoral three-dimensional surface, as captured in the series of images; and
for a detected spot which is identified as being from two distinct projector rays r based on the three-dimensional position computed by the correspondence algorithm, identify the detected spot as being from one of the two distinct projector rays r by identifying the detected spot as a tracked spot s moving along the one of the two distinct projector rays r.

14. The intraoral scanning system according to claim 8 , wherein the processor is further to:
run a correspondence algorithm to compute respective three-dimensional positions of a plurality of detected spots on the intraoral three-dimensional surface, as captured in the series of images, and
identify a weak spot whose three-dimensional position was not computed by the correspondence algorithm as being a projected spot from a particular projector ray r, by identifying the weak spot as being a tracked spot s moving along the path of pixels corresponding to particular projector ray r.

15. The intraoral scanning system according to claim 8 , wherein the processor is further to compute respective three-dimensional positions on the intraoral three-dimensional surface at an intersection of the projector ray r and the respective camera rays corresponding to the tracked spot s in each of the series of images across which spot s was tracked.

16. An intraoral scanning system, comprising:
an intraoral scanner comprising one or more cameras and one or more structured light projectors, the in

Assignees

• Align Technology Inc

Inventors

• Saphier Ofer
• Levy Tal
• Peleg Gal
• Dafna Eliran
• Ozerov Sergei
• Verker Tal
• Makmel Nir
• Atiya Yossef

Classifications

• G06T7/521

  from laser ranging, e.g. using interferometry; from the projection of structured light · CPC title

• H04N1/00018

  Scanning arrangements · CPC title

• H04N13/204 Primary

  using stereoscopic image cameras (stereoscopic photography G03B35/00) · CPC title

• G01B11/25

  by projecting a pattern, e.g. {one or more lines,} moiré fringes on the object (G01B11/255 takes precedence {; image analysis for depth or shape recovery G06T7/50}) · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title