Visual fluid animation via lifting wavelet transform

Abstract

While small‐scale fluid details are crucial elements for the creation of visually pleasing fluid animations, their synthesis often requires heavy computation with traditional grid‐based fluid simulation methods. This paper proposes a novel method for enhancing the appearance of small‐scale details through frequency‐domain analysis. Different from previous work, our method detects and improves fluid details in the frequency‐domain via lifting wavelet decomposition. Based on a coarse‐to‐fine mechanism, the lifting wavelet composition first transforms the velocity in a fine grid into the frequency domain. Next, the velocity field is enhanced separately for different frequency bands. A novel velocity fusion method is developed for the enhancement of low‐frequency parts. On the other hand, high‐frequency parts are enhanced using a specially designed vorticity confinement method. Finally, the application of the inverse lifting wavelet transform determines the final velocity field with increased fine details. Our method can generate perceptually interesting fluid details, matching human visual perception theory. The results of various experiments validate the effectiveness and efficiency of our method. Copyright © 2014 John Wiley & Sons, Ltd.