INTRAORAL3D SCANNER EMPLOYlNG MULTIPLE MINIATURE CAMERAS AND MULTIPLE MINIATURE PATTERN PROJECTORS

Abstract

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. 20 28.30 22 52 176 100 95 26 94 5824 H1 60 99 56 B S / 4 176 118 Processor 32 32 96 50 32 FIG. 1 20 28.30 22 52 176 100 95 26 94 5824 H1 60 99 56 B S / 4 176 118 Processor 32 32 96 50 32 FIG. 1 20 25 20 22 39 28 M ar 2 02 5 2 0 2 5 2 0 2 2 3 9 2 8 M a r 2 0 2 5 w o 2 0 2 0 / 2 6 4 0 3 5 aB1 / 9 4 P C T / U S 2 0 2 0 / 0 3 9 4 3 8

Claims

1. A method comprising:driving each one of one or more light sources to project light on an intraoral threedimensional surface;driving each one of one or more cameras to capture a plurality of images of the intraoral three-dimensional surface; andbased on stored calibration data for the one or more light sources and for the one or more cameras, using a processor to perform the following, comprising:running a correspondence algorithm to compute respective three-dimensional positions on the intraoral three-dimensional surface of a plurality of features of the projected light;collecting data at a plurality of points in time, the data including the computed respective three-dimensional positions on the intraoral three-dimensional surface of the plurality of features; andusing the collected data to recalibrate the stored calibration data.

2. The method of claim 1 wherein the one or more cameras comprises more than one camera, namely a plurality of cameras.

3. The method of claim 2 wherein each light source is a structured light projector, and the structured light projectors are driven to project a light pattern on an intraoral surface, and the plurality of cameras are driven to capture an image of said projection such that the image captured by each camera includes a portion of the projected light pattern.

4. The method of claim 3 wherein each camera includes a camera sensor that has an array of pixels, for each of which there exists a corresponding camera ray, the camera ray comprising a ray in 3D space originating from the each pixel and whose direction is towards an object being imaged, and for each of the projected features of the light pattern from each projector there exists a corresponding projector ray, and the calibration data comprises values (a) for camera rays of a plurality of pixels on the camera sensor and (b) for projector rays corresponding to a plurality of projected features of the light pattern from each of the projectors.2025202239   07 Sep 20265. The method of claim 4 comprising performing an assessment of a current calibration wherein for a given projector ray the processor computes respective three-dimensional positions on the intraoral surface of a plurality of detected features from the given projector ray at different points in time to define an updated path of pixels and in the event that the updated path of pixels does not fall on a camera sensor path of pixels that corresponds to that projector ray in the stored calibration data, the processor varies stored calibration values so as to reduce a difference between the updated path of pixels and the camera sensor path of pixels that corresponds to that projector ray in the stored calibration data.

6. The method of claim 5 wherein the assessment of current calibration is performed automatically on a periodic basis or in response to a criterion having been met.

7. The method of claim 4 wherein recalibrating the stored calibration data comprises varying stored calibration values indicating the camera rays of at least some of the one or more cameras.

8. The method of claim 4 or 7 wherein recalibrating the stored calibration data comprises varying one or more parameters of a parametrized camera calibration function that defines the camera rays in order to reduce the difference between: (i) the computed respective three-dimensional positions on the intraoral three-dimensional surface of the plurality of features of the projected light pattern; and (ii) the stored calibration values indicating respective camera rays corresponding to each pixel on the camera sensor where a respective one of the plurality of features should have been detected.

9. An intraoral scanning system comprising an intraoral scanning device that includes a plurality of cameras, one or more structured light projectors and the intraoral scanning system further comprising a processor and wherein the system is configured to:drive each one of one or more light sources to project light on an intraoral threedimensional surface;drive each one of the plurality of cameras to capture a plurality of images of the intraoral three-dimensional surface; andbased on stored calibration data for the one or more light sources and for the plurality of cameras, using the processor to perform the following, comprising:run a correspondence algorithm to compute respective three-dimensional positions on the intraoral three-dimensional surface of a plurality of features of the projected light;2025202239   07 Sep 2026collect data at a plurality of points in time, the data including the computed respective three-dimensional positions on the intraoral three-dimensional surface of the plurality of features; anduse the collected data to recalibrate the stored calibration data;wherein each light source is a structured light projector, and the structured light projectors are driven to project a light pattern on an intraoral surface, and the plurality of cameras are driven to capture an image of said projection such that the image captured by each camera includes a portion of the projected light pattern.

10. The intraoral scanning system of claim 9 wherein each camera includes a camera sensor that has an array of pixels, for each of which there exists a corresponding camera ray, the camera ray comprising a ray in 3-D space originating from the each pixel and whose direction is towards an object being imaged, and for each of the projected features of the light pattern from each projector there exists a corresponding projector ray, and the calibration data comprises values (a) for camera rays of a plurality of pixels on the camera sensor and (b) for projector rays corresponding to a plurality of projected features of the light pattern from each of the projectors.

11. The intraoral scanning system of claim 10 comprising performing an assessment of a current calibration wherein for a given projector ray the processor computes respective three-dimensional positions on the intraoral surface of a plurality of detected features from the given projector ray at different points in time to define an updated path of pixels and in the event that the updated path of pixels does not fall on a camera sensor path of pixels that corresponds to that projector ray in the stored calibration data, the processor varies stored calibration values so as to reduce a difference between the updated path of pixels and the camera sensor path of pixels that corresponds to that projector ray in the stored calibration data.

12. The intraoral scanning system of claim 11 wherein the assessment of current calibration is performed automatically on a periodic basis or in response to a criterion having been met.

13. The intraoral scanning system of claim 10 wherein recalibrating the stored calibration data comprises varying stored calibration values indicating the camera rays of at least some of the one or more cameras.2025202239   07 Sep 202614. The intraoral scanning system of claim 10 or 13 wherein recalibrating the stored calibration data comprises varying one or more parameters of a parametrized camera calibration function that defines the camera rays in order to reduce the difference between: (i) the computed respective three-dimensional positions on the intraoral three-dimensional surface of the plurality of features of the projected light pattern; and (ii) the stored calibration values indicating respective camera rays corresponding to each pixel on the camera sensor where a respective one of the plurality of features should have been detected.

15. A computer program product configured to program a programmable processor to perform a method comprising:driving each one of one or more light sources to project light on an intraoral threedimensional surface;driving each one of one or more cameras to capture a plurality of images of the intraoral three-dimensional surface; andbased on stored calibration data for the one or more light sources and for the one or more cameras, using a processor to perform the following, comprising:running a correspondence algorithm to compute respective three-dimensional positions on the intraoral three-dimensional surface of a plurality of features of the projected light;collecting data at a plurality of points in time, the data including the computed respective three-dimensional positions on the intraoral three-dimensional surface of the plurality of features; andusing the collected data to recalibrate the stored calibration data.

16. The computer program product of claim 15 wherein the one or more cameras comprises more than one camera, namely a plurality of cameras.

17. The computer program product of claim 16 wherein each light source is a structured light projector, and the structured light projectors are driven to project a light pattern on an intraoral surface, and the plurality of cameras are driven to capture an image of said projection such that the image captured by each camera includes a portion of the projected light pattern.2025202239   07 Sep 202618. The computer program product of claim 17 wherein each camera includes a camera sensor that has an array of pixels, for each of which there exists a corresponding camera ray, the camera ray comprising a ray in 3-D space originating from the each pixel and whose direction is towards an object being imaged, and for each of the projected features of the light pattern from each projector there exists a corresponding projector ray, and the calibration data comprises values (a) for camera rays of a plurality of pixels on the camera sensor and (b) for projector rays corresponding to a plurality of projected features of the light pattern from each of the projectors.

19. The computer program product of claim 18 comprising performing an assessment of a current calibration wherein for a given projector ray the processor computes respective three-dimensional positions on the intraoral surface of a plurality of detected features from the given projector ray at different points in time to define an updated path of pixels and in the event that the updated path of pixels does not fall on a camera sensor path of pixels that corresponds to that projector ray in the stored calibration data, the processor varies stored calibration values so as to reduce a difference between the updated path of pixels and the camera sensor path of pixels that corresponds to that projector ray in the stored calibration data.

20. The computer program product of claim 19 wherein the assessment of current calibration is performed automatically on a periodic basis or in response to a criterion having been met.

21. The computer program product of claim 18 wherein recalibrating the stored calibration data comprises varying stored calibration values indicating the camera rays of at least some of the one or more cameras.

22. The computer program product of claim 18 or 21 wherein recalibrating the stored calibration data comprises varying one or more parameters of a parametrized camera calibration function that defines the camera rays in order to reduce the difference between: (i) the computed respective three-dimensional positions on the intraoral three-dimensional surface of the plurality of features of the projected light pattern; and (ii) the stored calibration values indicating respective camera rays corresponding to each pixel on the camera sensor where a respective one of the plurality of features should have been detected.

23. A computing device programmed with the computer program product of any one of claims 15 to 22.

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