Real-time decompression and visualization of animated volume data

Interactive exploration of animated volume data is required by many application, but the huge amount of computational time and storage space needed for rendering does not yet allow the visualization of animated volumes. In this paper, we introduce an algorithm running at interactive frame rates using 3D wavelet transforms that allows for any wavelet, motion compensation techniques and various encoding schemes of the resulting wavelet coefficients to be used. We analyze different families and orders of wavelets for compression ratio and the introduced error. We use a quantization that has been optimized for the visual impression of the reconstructed volume, independent of the viewing algorithm. This enables us to achieve very high compression ratios while still being able to reconstruct the volume with as few visual artifacts as possible. A further improvement of the compression ratio has been achieved by applying a motion compensation scheme to exploit temporal coherency. Using these schemes, we are able to decompress each volume of our animation at interactive frame rates, while visualizing these decompressed volumes on a single PC. We also present a number of improved visualization algorithms for high-quality display using OpenGL hardware running at interactive frame rates on a standard PC.