X-Ray Volume Rendering by Hierarchical Wavelet Splatting

This paper is concerned with X-ray volume visualization by means of wavelet splatting, a wavelet-based extension to splatting. Wavelet splatting allows multiresolution visualization of volume data. While a user is interacting with the data, only low resolution images are computed. When interaction ceases, the image is refined incrementally. We discuss a particular implementation of wavelet splatting which was proposed previously, and show that certain rendering artefacts appear in the low resolution images, due to the particular ordering of the wavelet coefficients. We propose a new variant that uses a different ordering, and computes low resolution images based on the wavelet approximation coefficients only. This variant does not suffer from artefacts, and is faster by a factor of two to three.