Based On Ct Virtual Endoscopy System

Virtual Endoscopy is a very hot object in recent research. It is an application of virtual reality in modern medicine. As a multidisciplinary research field ,it incorporates the knowledge about Computer Graphics, Image Processing, Scientific Computing Visualization , Virtual Reality, and something in medicine . It is a non-touched medical diagnoses method since it avoids the risk of invading body when the actual optical endoscopy is used. The aim of Virtual Endoscopy system research is to provide trusty means for medical diagnoses, and to spread the application to precision orientation of surgery , personnel planning and training ,etc.The structure and modules arc surveyed in this thesis . Some key techniques existing in virtual endoscopy system are also studied . The research about VE consists of Image pretreatment (eg. interpolation and filter) , segment and abstraction of tissues , 3D construction , path planning , and real-time rendering.Marching Cubes is a classical algorithm about isosurface abstraction from regulated volume data. The process of MC is discussed in detail . A more efficient algorithm based on MC and region growing is proposed. And the new method of calculate the normal is also given.In path planning , a faster and a more efficient algorithm based on distance transform is designed . The center point of the hollow tissue is decided by the start point and end point . The distance from inner voxels to boundary surface was computed in section plane. The voxel point with local maximum distance value ( the distance value of a point in section plane is larger than its neighbor voxels' distance value) was taken as the center point. The computation is reduced since it is not executed in 3D space.In VE fly through , the model of virtual camera is defined and its geometric loccation and behavior is described.Future researches are pointed out considering the shortcomings and experiences of our system and the development trend.