US 12,336,765 B2
Ray-free dental x-ray periapical film virtual imaging method based on virtual reality
Xun Cao, Jiangsu (CN); Yidi Zhang, Jiangsu (CN); Hao Zhu, Jiangsu (CN); Zhuoyi Liao, Jiangsu (CN); and Weibin Sun, Jiangsu (CN)
Assigned to NANJING UNIVERSITY, Jiangsu (CN)
Appl. No. 17/628,694
Filed by NANJING UNIVERSITY, Jiangsu (CN)
PCT Filed Jul. 14, 2020, PCT No. PCT/CN2020/101916
§ 371(c)(1), (2) Date Jan. 20, 2022,
PCT Pub. No. WO2021/017819, PCT Pub. Date Feb. 4, 2021.
Claims priority of application No. 201910687262.2 (CN), filed on Jul. 29, 2019.
Prior Publication US 2022/0265356 A1, Aug. 25, 2022
Int. Cl. G09B 23/28 (2006.01); A61B 1/06 (2006.01); A61B 6/03 (2006.01); A61B 6/51 (2024.01); A61B 34/10 (2016.01); G06T 19/00 (2011.01); A61B 34/20 (2016.01)
CPC A61B 34/10 (2016.02) [A61B 1/0605 (2022.02); A61B 6/032 (2013.01); A61B 6/51 (2024.01); G06T 19/003 (2013.01); A61B 2034/104 (2016.02); A61B 2034/107 (2016.02); A61B 2034/2055 (2016.02)] 6 Claims
OG exemplary drawing
 
1. A ray-free dental X-ray periapical film virtual imaging method based on virtual reality (VR), comprising the following steps:
S1: using VR hardware to construct a spatial positioning system, wherein the positioning system comprises a base station and a tracker, a dental film machine is disposed within a visible range of the positioning system, and the tracker is fixed on a tube of the dental film machine and is able to implement a tracing function without a head mounted display; and acquiring an attitude matrix and position data of the tracker;
S2: scanning a plurality of teeth, and reconstructing a three-dimensional (3D) digital model of a dentition; and segmenting the 3D digital model to respectively acquire a tooth shell model and a pulp cavity model, then forming the two models into a preform, and setting corresponding translucent materials respectively for the two models according to actual tooth structural characteristics;
S3: constructing a virtual imaging environment for photographing a dental periapical film, adding a plurality of planes and cylinders around the teeth to simulate a background in a dental X-ray film, measuring the size of a bounding box of the 3D digital model of the dentition and the size of a bounding box of a dentition model in the real world, and calculating the ratio between the two; and adjusting the sizes of the tooth shell model and the pulp cavity model in the virtual imaging environment, and setting reasonable positions and orientations for light and a virtual camera;
S4: for the attitude matrix and the position data of the tracker acquired in step S1, converting the attitude matrix into an Euler angle, and then assigning, by means of a network communication module, same along with the position data, to the virtual camera in real time, and replacing the virtual camera with the tracker;
S5: placing the tube right in front of the teeth, aligning same with the teeth, measuring a physical distance between the tooth in the middle of the dentition and the tracker, and calibrating the position of the 3D digital model of the dentition in the virtual environment according to the position of the tracker at this time so as to align with the real world; and
S6: adjusting the position and orientation of the tube, and rendering a corresponding virtual dental X-ray periapical film.