Foveated Real-Time Path Tracing in Visual-Polar Space

Matias Koskela, Atro Lotvonen, Markku Mäkitalo, Petrus Kivi, Timo Viitanen, Pekka Jääskeläinen

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

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Computing power is still the limiting factor in photorealistic real-time rendering. Foveated rendering improves perceived quality by focusing the rendering effort on where the user is looking at. Applying foveated rendering to real-time path tracing where we must work on a very small number of samples per pixel introduces additional challenges; the rendering result is thoroughly noisy and sparse in the periphery. In this paper we demonstrate foveated real-time path tracing system and propose a novel Visual-Polar space in which both real-time path tracing and denoising is done before mapping to screen space. When path tracing a regular grid of samples in Visual-Polar space, the screen space sample distribution follows the human visual acuity model, making both the rendering and denoising 2:5x faster with similar perceived quality. In addition, when using Visual- Polar space, primary rays stay more coherent, leading to improved utilization of the GPU resources and, therefore, making ray traversal 1.3 - 1.5x faster. Moreover, Visual-Polar space improves 1 sample per pixel denoising quality in the fovea. We show that Visual-Polar based path tracing enables real-time rendering for contemporary virtual reality devices even without dedicated ray tracing hardware acceleration.
Original languageEnglish
Title of host publicationProceedings of 30th Eurographics Symposium on Rendering
PublisherThe Eurographics Association
ISBN (Electronic)978-3-03868-095-6
Publication statusPublished - Jul 2019
Publication typeA4 Article in conference proceedings
EventEurographics Symposium on Rendering - Strasbourg, France
Duration: 10 Jul 201912 Jul 2019


ConferenceEurographics Symposium on Rendering

Publication forum classification

  • Publication forum level 1


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