Real-Time Denoising of Volumetric Path Tracing for Direct Volume Rendering

Direct Volume Rendering (DVR) using Volumetric Path Tracing (VPT) is a scientific visualization technique that simulates light transport with objects' matter using physically-based lighting models. Monte Carlo (MC) path tracing is often used with surface models, yet its application for volumetric models is difficult due to the complexity of integrating MC light-paths in volumetric media with none or smooth material boundaries. Moreover, auxiliary geometry-buffers (G-buffers) produced for volumes are typically very noisy, failing to guide image denoisers relying on that information to preserve image details. This makes existing real-time denoisers, which take noise-free G-buffers as their input, less effective when denoising VPT images. We propose the necessary modifications to an image-based denoiser previously used when rendering surface models, and demonstrate effective denoising of VPT images. In particular, our denoising exploits temporal coherence between frames, without relying on noise-free G-buffers, which has been a common assumption of existing denoisers for surface-models. Our technique preserves high-frequency details through a weighted recursive least squares that handles heterogeneous noise for volumetric models. We show for various real data sets that our method improves the visual fidelity and temporal stability of VPT during classic DVR operations such as camera movements, modifications of the light sources, and editions to the volume transfer function.Comment: 13 pages, 19 figures, project page available at http://www.j4lley.com/content/publications/2020-ieee-tvcg-mcdvr-denoising/index.html IEEE Transactions on Visualization and Computer Graphics (2020

BME VIK Annual Research Report on Electrical Engineering and Computer Science 2016

PrefaceSince being established in 1949, the Faculty of Electrical Engineering and Informatics (VIK) BME has played a flagship role in the development of electronics, IT and computer science in Hungary. We are proud of combining engineering applications with sound scientific results, which is the assurance of high-level industrial collaboration leading to novel results and innovation. The various collaborations with our industrial partners has made it clear that the industry expects methods and results which make their industrial processes more effective and increase productivity and quality. Thus, participation in these collaborations give a competitive edge and ensure the continuous development of VIK. These factors have positioned our Faculty as a significant source of knowledge transfer and a treasured partner in various cooperation activities.The current paper gives a brief account of the results achieved at the Faculty of Electrical Engineering and Informatics in the year 2016 and, at the same time, tries to encompass the research activities conducted at different departments of the Faculty. We believe that this survey proves to be an informative summary about our scientific and technological contributions made in the year 2016.László Jakab (dean, BME VIK)János Levendovszky (vice-dean in charge of scientific affairs, BME VIK