VIRIM, A Real-Time Volume Rendering System for Medicine

VIRIM, a real-time direct volume rendering system is presented. The system is freely programmable and supports models like a-compositing, front-to-back (back-to-front) techniques, and the slab method. The hardware system is divided into two units, a geometry unit and a raycast unit. The geometry unit performs resampling and gradient estimation and is mapped directly into hardware. It supports different resampling filters in order to reduce resampling artifacts. The raycast unit consists of 16 digital signal processors that perform the programmable ray- casting. The software of VIRIM is layered and provides manipulation tools for the data during real-time visualization like arbitrary gray-value mapping and setting the region of interest. The system is under test and will be available as prototype in 1995