Fast Volume Rendering Using a Wavelet Transformation

In volume data exploration, it is necessary to visualize the volume data in conjunction with a pseudocolor display, and to change a transfer function based on the purpose of the observation. This paper proposes a fast volume rendering method when a transfer function undergo change. The proposed method calculates a histogram of volume data along a cast ray, and the histogram is wavelet-transformed in a pre-process. The rendered image for an arbitrary transfer function is generated by multiplying a series of coefficients of basis functions, after the specified transfer function is also wavelet-transformed. We also propose a method for displaying iso-surfaces by making use of a wavelet transformation. Several examples of the volume data visualization demonstrate the usefulness of the proposed method for observing unknown volume data.