Research On Key Technology Of C-arm Based Surgical Navigation And Development Of Application System

Image-guided surgical (IGS)technology is a major research field of the computer assisted surgery navigation. C-arm based surgical navigation technology is a typical branch of IGS technology. A C-arm based surgical navigation system use C-arm acquired fluoroscopic images for surgical process guiding. In order to fulfill the surgical navigation functions, the fluoroscopic images must be processed to identify certain objects and extract relevant data; the distortions of the fluoroscopic images must be corrected; the C-arm system must be calibrated to get relevant imaging parameters. Nevertheless, at present, there are still many disadvantages on the research of these key techniques. The disadvantages mainly focus on the follows aspects: the object identification and relevant data extraction algorithms are not robust and accurate enough; the image distortion correction accuracy is too low, the distortion correction algorithms are too sensitive to certain element distortions, the existing algorithms don`t count for correction of local image distortions; the existing C-arm calibration algorithms are too complicated, there are too much transition links in the existing algorithms, the ultimate calibration accuracy is low. In addition, current research of C-arm based surgical navigation techniques mainly focus on software, few attention was paid on the design of C-arm calibration target and surgical tools. In fact, optimization design of these mechanical parts are of great importance for the enhancement of overall surgical navigation performance. In this paper, we focus on the research of the above mentioned key techniques. The main contents are as follows.1. A CHT(Circle Hough Transform) and CC(Connected Components) processing combined method was brought forward for object identification and data extraction. Take the CHT output accumulative space as a special image and process it to get a binary image, in the following, the binary image is processed with a special CC analysis method to get the ultimate data. Compared with the existing methods, the new one is more robust and accurate.2. An MLS(Moving Least Squares) and MBA(Multilevel B-spline Approximation) integrated method was brought forward for fluoroscopic images distortion correction. The method possesses advantages of the existing global correction methods and local correction methods simultaneously. In addition, the new method possesses excellent local image distortion correction performance.3. Evaluated the existing camera calibration method. On this basis, decided on Faugeras`s calibration method for C-arm imaging system calibration. The calibration method was further simplified. The simplified method is more easy for execution and possesses higher efficiency. Combined with improved C-arm calibration target, the C-arm calibration quality can be enhanced by using Faugeras`s calibration method.4. Evaluated the existing C-arm calibration targets, analyzed their shortcomings. On this basis, proposed design of an improved C-arm calibration target. Different fabricating techniques are to be used for the improved calibration target. The improved calibration target is to be more accurate and cheap, it is also favorable to enhance the overall surgical navigation performance.In this paper we put emphasis on researching key technology of C-arm surgical navigation system. We designed relevant computerized algorithms. On this basis, we developed a tentative navigation system, SpiNav-I(Spine Navigation-I), to assist inserting screws in the pedicles of vertebral arches. Since computer assisted surgical navigation technologies are attracting more and more attention. I think my research work will benefit Intellectual property rights autonomy of our country in the field of computer assisted surgical navigation.