Optimal Viewpoint Selection For Volume Rendering

In recent years, research and application of viewpoints selection in visualization of 3D datasets has become an important task in volume rendering. Due to the slow frame-rates, locating an optimal viewpoint or a series of optimizational viewpoints is absolutely necessary to improve both the speed and efficiency of data understanding.Based on the related research at home and abroad, this article discussed several key problems in optimal viewpoint selection for volume rendering. The main research work includes:(1) Discuss the volume rendering method with translucence and Phong shading effect based on 3D texture mapping and blending on PC platform. Volume rendering with 3D texture hardware-assistant, OpenGL and OpenGL extension, texture mapping and blending is achieved. The experiment result with medical DICOM format images and RAW format images indicates that the method presented may produce high-quality 3D images on general PC.(2) Provides an overview of viewpoint evaluation methods for volume rendering based on information entropy at home and abroad. Based on related research, an improved evaluation method of viewpoint entropy based on projected views is presented. This method utilizing the opacity, luminance and structure features of the projected views of three-dimensional volume datasets, constructed a viewpoint evaluation function to identify the importance of voxels and the structural information within the volume data. In addition, this paper also discussed the viewpoint quality assessment outside the normal information entropy technology, present a simple method of viewpoint evaluation based on edge detection.(3) During the process of locating optimal viewpoint, artificial intelligent algorithms including PSO, NM-PSO and SFLA are introduced. Combined with constructed viewpoint evaluation function, intelligence algorithms are used to direct and optimize the search process of optimal viewpoint, so as to acquire a global optimal viewpoint or a series of optimizational viewpoints, focus the important structural information and region of interest more effectively.