Surface Reconstruction Of Spine Using 2D Contour Lines Based On Freehand 3D Ultrasound

With the development of medical imaging technology, medical images play an increasingly important role in medical diagnosis,2D ultrasound images have a mature and widely used in medical diagnosis because of its non-radiation, flexibility and low cost. But 2D ultrasound images only show the section information of the organs, doctors need to use many images to estimate the 3D structure of the organ by experience, so, the diagnosis is not accurate enough. If the human organs are displayed directly in the form of 3D images, it must help doctors to conduct a comprehensive and accurate analysis. In the research of 3D ultrasound imaging technology,3D freehand ultrasound only needs to fix the position sensor on the probe of traditional ultrasound,3D reconstruction can be realized. It is convenient and flexible, so 3D freehand ultrasound has become the main research direction.Calibration of ultrasound probe was a crucial step in 3D freehand ultrasound, the calibration results directly affected the accuracy of 3D reconstruction. This paper used the method of single-wall phantom to calibrate the probe, accurate match of 2D images and position information was the key step to affect the calibration. In order to improve the calibration accuracy and reduce the time, a simple and fast time match method, continuous frame control method, was presented in this paper, the time error was determined by multi group experiments. This method effectively reduced the complexity of the time, and had a significant effect on improving the real-time performance of the whole system.The methods of 3D reconstruction mainly include surface reconstruction and volume reconstruction, the result of the volume reconstruction for spine is not satisfactory because of the characteristics of the ultrasound image in 3D ultrasound reconstruction of spine. Therefore, this paper proposed a method of surface reconstruction based on 2D contour lines in 3D reconstruction of spine, the spine model and the human spine images were collected by ultrasound, and then manually depicting the contour of the spine, and finally contours were used to reconstruct the surface profile of the spine. A vertebra model was used to reconstruct, the result reflect the actual surface of vertebra well, and then, spinal model and three groups of real human spine were used to do the reconstruction experiment. Experimental results show that the reconstruction of the spine model is better than the real human spine's, but all in all, the result of spinal reconstruction based on 2D contours could respond to the surface profile of the spine well, and it can give doctors a better help in the diagnosis of the spine.