Template-based approach for virtual-endoscopic navigation

Three-dimensional (3D) digital images arise in many scientific applications. In an application such as virtual endoscopy, interactive navigation through the 3D image data - i.e., the interactive creation of an animated sequence of views - can reveal more information than single static two-dimensional (2D) views. For this case, the 3D image acts as a "virtual environment" representing the imaged structures, and a computer-based system can serve as a tool for navigating through the environment. But such navigation must occur at interactive speeds if it is to be practical. This demands fast volume visualization from arbitrary viewpoints. We present an inexpensive, fast, volume-rendering method that can generate a sequence of views at interactive speeds. The method is based on the approximate discrete Radon transform and the temporal coherence concept. The method forms part of a system that permits dynamic navigation through 3D digital images. We provide pictorial and numerical results illustrating the performance of our method.