Research On Virtual Eversion Arithmetic And Virtual Rotation Arithmetic Of Colon

With the development of computer technology, virtual reality technology has been increasingly applied to the medical education and clinical diagnosis. As for human hollow structures such as colon , the commonly used method for virtual reality is the technique of virtual endoscopy , virtual unfolding and flattening and virtual eversion. However these methods have their own disadvantages. The visual angle of virtual endoscopy is small. Virtual unfolding and flattening distort original shapes and relative configurations. The existing virtual eversion method is time consuming and we can not observe the internal angle part of hollow structureIn this paper, a new method for virtual process of human hollow structures is presented, which is called"virtual rotation". The main idea of virtual rotation is to rotate the hollow structures with the centerline as the axis to rotate the internal angle part to the external angle. A rotation algorithm is proposed in this paper. Firstly we straighten the hollow structures by virtual technology. Then the virtual eversion and rotation algorithm is used. Finally the processed image is mapped back to the original image. The advantages of this method include the direct visualization of the internal angle part and the close correlation to the important features of the global anatomy. What is more, a new fast algorithm is introduced to overcome the disadvantage of time consuming of the existing electrical field algorithm. In this algorithm the distance map is well used during the processing.At last gradient method is put forward. By using gradient method, the precision of centerline can be improved and processing speed of virtual eversion can be increased.