Three-dimensional Reconstruction Of CT Image Based On Ray Casting Algorithm And Partition Clipping

We are easy to get the two-dimensional slice images of the lesion sites through computed tomography (CT), magnetic resonance (MR) equipment. But two-dimensional slice images can not show organs in three dimensions, and is not favorable for doctor to treat the condition of the patients overall. Therefore, the studying and completing of segmentation and clipping in basic research and clinical application have a certain value.This article used the Visualization Toolkit VTK (Visualization Toolkit) visualization systems to complete the physical features of volume rendering, segmentation and clipping. VTK is a toolbox which designed based on the object-oriented approach, with powerful visual and graphic image processing, is an important tool for the field of three-dimensional reconstruction. This article researched and analyzed the VTK visualization tools, summarized characteristics, composition and class library's structure of visualization tools VTK.Article analyze and achieve the algorithm of ray casting, and give the basic processes of ray casting algorithm, through data acquisition, data processing, coordinate transformation, rendering of voxel and compositing images to complete the volume rendering of three-dimensional reconstruction. Through adding cubic bounding box and change the distance sampling method, ray-casting algorithm was improved to speed up the rate of three-dimensional reconstruction.In order to observe the internal detail information of volume data more clearly and diagnose, we cut the image data through the volume data to get the parts of body which we interested in, and we slice the details of volume data in clipping plane from the volume data which was reconstructed, and mainly studied and implemented how to clip the slices of the partly image of the head, through the technique of cutting the image we can directly get the interested parts of the complete reconstruction; we clip the slice in coronal and sagittal, through the technique of slice clipping, to display the internal details of the full body data, and make the observation of the medical facilitates.This article used VC++ 6.0 and VTK to complete the algorithm, and developed the reconstruction system of CT images.