An array based design for Real-Time Volume Rendering

Abstract

This paper describes a new algorithm and hardware design for the generation of two dimensional images from volume data using the ray casting technique. The algorithm is part of an image generation system that is broken down into three subsystems. The first subsystem stores the input data in a buffered memory using a rearrangement of the original ad­ dress value. The second subsystem reads data points from the buffered memory and shifts the data to computational el­ ements in order to complete the viewing calculations for the image synthesis process. The final stage takes the results of the viewing calculations combined with the original input data to complete the surface rendering and pixel compositing to create the final image.This paper focusses on the second subsystem which con­ sists of two, two dimensional arrays of processing elements. The first array performs a limited angle, single dimension ro­ tation by shifting the data. The second array performs a two dimensional ray casting operation where viewing rays are as­ signed to each processing element. The first stage is outlined in this paper and the final rendering stages are the subject of previous work. The hardware design associated with these algorithms is described and tested. It is estimated that this ar­ chitecture is capable of producing 384 x 384 pixel images at speeds of 15 frames per second for 256 data sets. Real time generation of images of volume data is important in scientific applications of volume visualization and computer graphics applications which use volume graphics.