Research On Volume Rendering Algorithms Of Medical Image Three-Dimensional Visualization

Visualization in Scientific Computing (VISC) is a rapidly developing image processing method, which use computer graphics or graphics principle in the process of large scale data computation. Because of its rendering image can clear display every details and internal structure of organs, assist doctors to make an operation scheme and preoperative simulation accurately and reliably, so it has important not only for clinical medicine, the practical value of medical research also has important academic value, also gradually become a hot research topic in the field of computer graphic image.Visualization in Scientific Computing is divided into surface reconstruction based on surface rendering and volume reconstruction based on volume rendering. This paper,mostly studies the technique of medical image three dimensional reconstruction. Analyze their domestic and overseas development prospect, meanwhile introduce the concepts of volume rendering,which include medical image volume data,several ways of image preprocessing,and typical algorithms of it.For the feature of direct volume rendering,we study speed technology from software and hardware.Directed towards the feature of medical image,we study the method of region. On the base of consulting many documents,the ray casting algorithm were analyzed and researched.A ray casting algorithm based on dynamic bounding sphere(DBS) is presented.Introduce DBS to reduce the amount and step of the light.By DBS to jumped empty triangle sections further,and the alogorithm filters the date of the original medical image.Therefore,the image quality is improved,and the speed of rebuild is quickened.what's more ,Taking use of the unchange and even change characteristics of geometry converted from a coordinate system to another coordinate system, we change the solution sequence of sample point coordinates ,which optimizes the process of re sampling and accelerates raycasing speed further.Finally, we implement our experiment on 3DMed open platform which provides open source code and comprehensive data interface solutions to enable researchers to test their algorithm by loading plugins dynamically.We use VC++6.0 to develop our plugins.The three—dimensional reconstruction result on 256 pieces real chest CT images hows that our method acquired better rendering effect and enhanced rendering speed through comparison of traditional ray casting algorithm in intersection testing and accelerate raytracing time.The experiment verifies the effectiveness of our method.