Patent ID: 11896461
Assignee: ALIGN TECHNOLOGY, INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC A  G  H | IPC A  G  H

Claim 7:
8. A method of generating a digital three-dimensional model of an intraoral surface, comprising:
driving a plurality of structured light projectors disposed in a probe at a distal end of an elongate handheld wand of an intraoral scanner to project a pattern of light on an intraoral surface, each structured light projector comprising at least one light source and a pattern generating optical element, wherein each structured light projector is configured to project a pattern of light defined by a plurality of projector rays by transmitting light from the at least one light source through the pattern generating optical element that uses at least one of diffraction or refraction to generate the pattern of light, wherein each of the plurality of structured light projectors projects respective distributions of discrete unconnected spots of light on the intraoral surface simultaneously or at different times, wherein each of the plurality of projector rays corresponds to a spot of the discrete unconnected spots of light, wherein the pattern of light comprises a non-coded structured light pattern, and wherein the discrete unconnected spots of light comprise an approximately uniform distribution of discrete unconnected spots of light;
driving two or more cameras disposed in the probe at the distal end of the elongate handheld wand to capture a plurality of images that depict at least a portion of the projected pattern of light on the intraoral surface;
driving at least one uniform light projector to project white light onto the intraoral surface, wherein at least one of the two or more cameras is to capture two-dimensional color images of the intraoral surface using illumination from the uniform light projector;
receiving the plurality of images that depict at least the portion of the projected pattern of light on the intraoral surface;
determining a correspondence between points in the pattern of light and points in the plurality of images that depict at least the portion of the projected pattern of light on the intraoral surface by:
accessing calibration data that associates camera rays corresponding to pixels on a camera sensor of each of the two or more cameras to projector rays of the plurality of projector rays; and
determining intersections of projector rays and camera rays corresponding to at least the portion of the projected pattern of light using the calibration data, wherein intersections of the projector rays and the camera rays are associated with three-dimensional points in space;
identifying three-dimensional locations of the projected pattern of light based on agreements of the two or more cameras on there being the projected pattern of light by projector rays at certain intersections; and

using the identified three-dimensional locations to generate the digital three-dimensional model of the intraoral surface.