The Design And Implementation Of Mandibular Movement Trajectory Tracking System

The mandible is an important part of the human oral cavity.Mandibular movement is very important for us to exercise functions such as chewing,swallowing and language.Today,in the medical field,especially in the field of biomedical engineering,the research on the mandibular movement trajectory is a hot spot for scholars from all over the world and has broad application prospects.People have been studying the tracking of mandibular movement trajectory for a long time.With the continuous advancement of technology in all fields of society,various mandibular movement trajectory tracking schemes have been continuously proposed,from the earliest magnetic steel type and photoelectric type,to the latest ultrasonic type.They have their limitations while meeting the requirements of the times.In this paper,through reading a large number of domestic and foreign literatures,the advantages and disadvantages of mandibular movement trajectory tracking schemes at home and abroad are analyzed and compared.Based on the existing algorithms,a new mandibular movement trajectory tracking algorithm is proposed.The mandibular movement trajectory is indirectly tracked by tracking the characteristic chessboard fixed to the mandible.Subsequently,through a reasonable planning of hardware architecture to accelerate algorithm,we get a system which has obvious advantages in portability,real-time and accuracy compared with other schemes.The main research contents of this paper include: the algorithm design of mandibular movement trajectory tracking system and the planning and implementation of the system.(1)Algorithm designThe algorithm is implemented in the order of corner extraction,corner selection,sub-pixel refinement and 3D coordinate transformation.The corner extraction is based on the Harris algorithm.The "Sobel + Connected Domain Marking" is used to extract the checkerboard contour,which reduces the amount of data detected by Harris and improves the detection accuracy.Corner selection is based on corner distance feature,sub-pixel refinement is based on image gray gradient,and 3D coordinate transformation is based on imaging geometry principle.(2)The planning and implementation of the system hardwareThe system is planned to be "FPGA+ARM+PC".The FPGA completes the hardware acceleration of the diagonal point extraction,the ARM completes the sub-pixel refinement,and the PC completes the 3D coordinate transformation.The pipeline architecture of the system is realized by combining the "ping-pong operation" with the FPGA,which improves the system data throughput.Through the cooperation of hardware and software,the system functions are well realized.The system test results show that the system can achieve 73 fps frame rate at 1280 *1024 resolution,and the system accuracy can reach 53(+20)um after rough measurement.Compared with other mandibular movement trajectory tracking systems,the system has better effects in real-time and accuracy.