Research On Real-time Computation Of Three-dimensional Digital Image Correlation And Its Biomedical Applications

Three-dimensional digital image correlation(3D-DIC)is a non-interferometric,non-contacting optical metrology for full-field shape and deformation measurements.After more than 20 years of development,its application areas have gradually expanded from the traditional experimental mechanics to biology,medical science,industrial measurement and other fields.At the same time,these applications also put forward higher requirements,such as real-time computing requirements.Based on these practical application requirements,this paper focuses on real-time research on 3D-DIC method and solving the practical problems of the applications of 3D-DIC in biomedical and medical field.Although scholars have done a lot of research on the computational efficiency of 3D-DIC,it cannot meet the requirements of real-time calculation for full-filed large-scale area with intensive sampling points yet,and can only realize real-time calculation under small scale and small deformation assumption.But specific applications,such as robot navigation,human virtual animation only need to assess the movement and deformation of key points.Therefore,Less-than-ideal alternative is to track the discrete points in real time based on 3D-DIC method.In chapter 2,we propose an integral pixel search method.Experiments show that compared with the traditional method,this method can improve the computational efficiency of 4-10 times.This chapter also compare feature-based method in computer vision field with 3D-DIC method,and compare circular mark with speckle mark.In the third chapter,based on the optimized 3D-DIC speckle mark tracking method,a navigation system for craniomaxillofacial surgery is designed.The principle prototype is made to verify accuracy and feasibility of the system.Compared with the traditional infrared operating system,the speckle mark points have the advantages of convenient layout and less space,and can meet the real-time tracking requirements for various small objects.In the system frame design,the problems of system registration,posture tracking under Lagrange coordinates,and tracking after interruption is solved.In the fourth chapter,the pulse signal acquisition system based on 3D-DIC measurement is built by simulating the process that getting the pulse signal feedback by using three fingers to press the acupoints with different strength.In this chapter,the pulse signals of different acupoints under different pressure are analyzed combined with traditional Chinese medicine theory and practical experience.The results verify the viewpoint "????" in traditional Chinese medicine.The pulse wave velocity is also calculated and discussed in the paper.At lower pressure,the pulse wave velocity is more accurate.The fifth chapter mainly studies the facial expression reconstruction and animation production based on natural texture.Calculation parameters are optimized to solve the problems of poor correlation of natural texture and large deformation.Incorrect matching points is also removed and the hole in reconstruction is repaired.The sixth chapter introduce applications of 3D-DIC method in the measurement of the back skin of the hand,the closure of Venus flytrap and the three-dimensional morphology of the printed circuit board,which solves a series of engineering problems such as lighting and speckle preparation.Compared with other methods,3D-DIC method can carry out accurate full-field measurement,which has great advantage in post-processing and analysis.