Research On 3D Dental Model Scanning Technology Based On Line Structure Light

The acquisition of 3D point cloud information based on line structure optical scanning tooth model for 3D reconstruction is a key research direction in the field of computer vision and medical dentistry,and is the most important link in the development of digital oral medicine in the future.Although the very mature dental impression printing technology has been developed in the 1960 s,this method has the problems of complicated printing process and long printing cycle compared with the three-dimensional reconstruction method of threedimensional scanning.This paper mainly studies the 3D tooth model scanning technology based on line structure light,and constructs a complete low-cost,mobile portable 3D dental model scanning system.This paper mainly completes the following work:(1)Completed the research and construction of hardware.For the overall demand analysis and hardware system analysis of 3D dental scanning technology and 3D point cloud acquisition technology,the research and analysis of stepper motor,camera and control board are mainly carried out,and a complete set of 3D dental model scanning hardware is designed.(2)Complete the research of camera calibration and system calibration.In order to achieve the mobility and operability of the system,according to the classic checkerboard calibration algorithm,an automatic calibration scheme is designed: the checkerboard is fixed vertically on the turntable,and the checkerboard rotation is used to automatically obtain the checkerboard at different angles.The image has achieved the purpose of automatic calibration,and the calibration process is simple,which improves the calibration efficiency of the dental model three-dimensional scanning system.The system calibration is to convert the picture coordinates into the camera coordinate system,convert the camera coordinates into the laser plane coordinate system,then convert the laser plane coordinates into the world inertial coordinate system by using the homogenous transformation matrix,and finally obtain the rotation principle according to the stepping motor.The rotation matrix converts the world's inertial coordinates to the world coordinate system.The calibration results show that the average error of the camera calibration parameters f x,f y,cx,cy for the Logitech C310 model is 1.38%,2.11%,0.51%,and 0.08%,respectively.(3)The research on laser strip extraction was completed.For the detection of light strips,the peak detection,centroid detection and segmentation Gaussian filter extraction effects are studied respectively.By improving the segmented Gaussian filter laser strip detection algorithm,an adaptive threshold segmented Gaussian filter is proposed.The laser extraction is performed,and the average threshold of the laser extraction of the segmented Gaussian filter with adaptive threshold is 20 ms.(4)Completed the implementation and testing of the 3D scanning systemAiming at the hardware construction of 3D dental scanning system and the realization and improvement of 3D point cloud technology,the scanning and scanning system was tested and precision tested.The final scanning error was 1.57%,which verified the availability of 3D dental scanning and point cloud acquisition system.