Study On Key Techniques Of Denture 3D Measurement Based On Linear-Structure Light

In recent years, people's requirements for oral health and oral cavity repair are increasing with the society modernization. The traditional manual method of denture manufacturing, which is time-consuming, lower precision and inefficient, has been no longer able to satisfy the clinical requirements. Therefore, the research based on optical measurement methods to gain 3D-geometric data of denture becomes the most hot subject in related areas.This paper studies and tests the key techniques of 3D profile measurement of denture according to the line structured light three-dimension vision system. The main contents of the thesis include demarcation technology of denture 3D measuring system and image registration techniques. Firstly, Based on structured-light 3D profile measurement system, an improved calibration method was proposed, which use a special slope of the cube as the calibration block. From the calibration block's translation, we will able to get every point height under space physical location in the camera image plane of the pixel value quickly and accurately. At the same time, combined with the every pixel value in each height of laser line, each point within the defined range can be demarcated. Secondly, the course of rough and accurate registration of point cloud data acquired'om left and the right camera is completed, which selected an algorithms based on Euclidean distance threshold as well as direction vector threshold of point cloud data to for obtaining registration of high precision. Thirdly, after calibration and image registration, use a module which has a height difference to test the accuracy of measurement system. Finally, use this method of calibration and image registration, the line structured light sensor and the image registration of two-eyes-visual system has been accomplished. The experiment platform of this paper is based on the denture preparation assessment system, which design with Northwest Medical limited company. And Through the test, the results prove that the measurement accuracy of measurement system is 0.04mm, the registration accuracy is 0.0041mm.