Research On Machine Vision Assisted Ultrasound Surgery Navigation System

Ultrasound-guided intervention has important applications in the treatment of varieties of diseases.As a branch of minimally invasive surgery,it has the advantages of high precision,short operation time,less damage,less complications and so on.But actually in the operation process,there are many problems.The technology does not apply to the surgical tool which can't be imaged clearly by the ultrasonic instrument.The guidance is not continuous and real-time enough,and the operation is not flexible enough.Moreover some of the existing surgery navigation equipment for ultrasound surgery also have the disadvantages of too large size,moving inconveniently,influencing the operation of doctors and so on.Therefore,in view of the problems existing,this thesis studies on machine vision assisted ultrasound surgery navigation system.This binocular stereo vision based navigation system can accurately track the surgical tool in real time,and display the fused location information of the surgical tool with the ultrasound image of lesions.The research contents are as follows:Firstly,this thesis presents an innovative hand-eye system at close quarters.Then,the hardware system and software system are completed.The hardware system includes binocular vision positioning device,the surgical tool with markers,image workstation,ultrasonic calibration device,and ultrasonic instrument.Additionally,a barcode marker was designed to assist in tracking the surgical tool,and an effective algorithm for marker detection and recognition is proposed,which can quickly and accurately extract the feature points of the markers.Furthermore,on the basis of N-line calibration model,an ultrasonic calibration device was designed.In order to solve the problem of coordinate transformation between the positioning device coordinate system and the ultrasound coordinates system,we used the method of spatial transformation technology and obtained the transfer matrix based on the Rodrigues formula.Finally,the prototype of the surgery navigation system was built,and some performance indicators of the prototype were tested.The results of experiments show that the surgery navigation system has location errors within 1mm,and the position information update frequency is 12~13Hz.All in all,the surgery navigation system has good performance on accuracy,stability and real time,it satisfies the requirements of medical surgery navigation.