Publications related to Path tracing

Aggregating Spatial and Photometric Context for Photometric Stereo

Photometric stereo, a computer vision technique for estimating the 3D shape of objects through images captured under varying illumination conditions, has been a topic of research for nearly four decades. In its general formulation, photometric stereo is an ...

EPFL2024

BigNeuron: a resource to benchmark and predict performance of algorithms for automated tracing of neurons in light microscopy datasets

Pascal Fua, Sean Lewis Hill, Jiancheng Yang, Xiang Li, Amos Sironi, Jian Zhou, Jie Zhou, Siqi Liu

BigNeuron is an open community bench-testing platform with the goal of setting open standards for accurate and fast automatic neuron tracing. We gathered a diverse set of image volumes across several species that is representative of the data obtained in m ...

2023

Void Lensing in Cubic Galileon Gravity

Jiaxi Yu, Cheng Zhao, Huanyuan Shan, Qiao Wang, Jun Zhang

Weak-lensing studies via cosmic voids are a promising probe of modified gravity (MG). The excess surface mass density (ESD) is widely used as a lensing statistic in weak-lensing research. In this paper, we use the ray-tracing method to study the ESD around ...

IOP Publishing Ltd2023

Investigation of the interplay between Electron-Cyclotron waves, suprathermal electrons and turbulence in tokamak plasmas

Jean Arthur Cazabonne

Electron-Cyclotron waves are routinely used in tokamaks to heat the plasma and to drive current through the electron channel. Their unique ability to drive very localized current renders them the main foreseen tool for neoclassical tearing mode mitigation ...

EPFL2023

Differentiable Physically Based Rendering: Algorithms, Systems and Applications

Merlin Eléazar Nimier-David

Physically based rendering methods can create photorealistic images by simulating the propagation and interaction of light in a virtual scene. Given a scene description including the shape of objects, participating media, material properties, etc., the sim ...

EPFL2022

Efficient and Accurate Physically-Based Differentiable Rendering

Delio Aleardo Vicini

Physically-based rendering algorithms generate photorealistic images of virtual scenes. By simulating light paths in a scene, complex physical effects such as shadows, reflections and volumetric scattering can be reproduced. Over the last decade, physicall ...

EPFL2022

Importance of 3D radiative transfer effects on high-resolution NO2 remote sensing in cities

Marc Damien Schwärzel

Urban air quality is a major concern in the context of human health since cities are at the same time emission hot spots and home to a large fraction of the world's population. Airborne imaging spectrometers may be a valuable addition to traditional air po ...

EPFL2022

Path Replay Backpropagation: Differentiating Light Paths using Constant Memory and Linear Time

Wenzel Alban Jakob, Delio Aleardo Vicini, Sébastien Nicolas Speierer

Differentiable physically-based rendering has become an indispensable tool for solving inverse problems involving light. Most applications in this area jointly optimize a large set of scene parameters to minimize an objective function, in which case revers ...

ASSOC COMPUTING MACHINERY2021

Content-Preserving Unpaired Translation from Simulated to Realistic Ultrasound Images

Devavrat Tomar, Lin Zhang

Interactive simulation of ultrasound imaging greatly facilitates sonography training. Although ray-tracing based methods have shown promising results, obtaining realistic images requires substantial modeling effort and manual parameter tuning. In addition, ...

Springer2021

A method to numerically determine the secondary electron yield considering effects of the surface morphology

Guang-Yu Sun, Ning Yang

Secondary electron emission (SEE) of solid materials due to electron bombardment is influenced by numerous properties of materials, where the surface condition plays a critical role in the value of secondary electron yield (SEY). Here, a 3D random microstr ...

2021

Modeling specular transmission of complex fenestration systems with data-driven BSDFs

Jan Wienold

A Bidirectional Scattering Distribution Function (BSDF) describes how light from each incident direction is scattered (reflected and transmitted) by a simple or composite surface, such as a window shade. Compact, tabular BSDFs may be derived via interpolat ...

2021

A Non-Exponential Transmittance Model for Volumetric Scene Representations

Wenzel Alban Jakob, Delio Aleardo Vicini

We introduce a novel transmittance model to improve the volumetric representation of 3D scenes. The model can represent opaque surfaces in the volumetric light transport framework. Volumetric representations are useful for complex scenes, and become increa ...

ASSOC COMPUTING MACHINERY2021

A Correlation-Based Electromagnetic Time Reversal Technique to Locate Indoor Transient Radiation Sources

Farhad Rachidi-Haeri, Marcos Rubinstein, Zhaoyang Wang, Qi Li

To overcome the multipath interference in locating transient electromagnetic (EM) radiation sources in an indoor environment, we propose a criterion that calculates the correlation between back-propagated signals from observation points, to be used in EM t ...

Institute of Electrical and Electronics Engineers2021

Light Path Gradients for Forward and Inverse Rendering

Tizian Lucien Zeltner

Physically based rendering is a process for photorealistic digital image synthesis and one of the core problems in computer graphics. It involves simulating the light transport, i.e. the emission, propagation, and scattering of light through a virtual scen ...

EPFL2021

Digital proximity tracing on empirical contact networks for pandemic control

Marcel Salathé

Digital contact tracing is a relevant tool to control infectious disease outbreaks, including the COVID-19 epidemic. Early work evaluating digital contact tracing omitted important features and heterogeneities of real-world contact patterns influencing con ...

Nature Research2021

Specular Manifold Sampling for Rendering High-Frequency Caustics and Glints

Wenzel Alban Jakob, Tizian Lucien Zeltner

Scattering from specular surfaces produces complex optical effects that are frequently encountered in realistic scenes: intricate caustics due to focused reflection, multiple refraction, and high-frequency glints from specular microstructure. Yet, despite ...

ASSOC COMPUTING MACHINERY2020

Slope-Space Integrals for Specular Next Event Estimation

Wenzel Alban Jakob, Tizian Lucien Zeltner, Guillaume Rémi Bruno Loubet

Monte Carlo light transport simulations often lack robustness in scenes containing specular or near-specular materials. Widely used uni- and bidirectional sampling strategies tend to find light paths involving such materials with insufficient probability, ...

ASSOC COMPUTING MACHINERY2020

Practical Product Path Guiding Using Linearly Transformed Cosines

Wenzel Alban Jakob

Path tracing is now the standard method used to generate realistic imagery in many domains, e.g., film, special effects, architecture etc. Path guiding has recently emerged as a powerful strategy to counter the notoriously long computation times required t ...

WILEY2020

Three-dimensional radiative transfer effects on airborne and ground-based trace gas remote sensing

Alexis Berne, Dominik Brunner, Thomas Wagner

Air mass factors (AMFs) are used in passive trace gas remote sensing for converting slant column densities (SCDs) to vertical column densities (VCDs). AMFs are traditionally computed with 1D radiative transfer models assuming horizontally homogeneous condi ...

2020

Image-Based Acquisition and Modeling of Polarimetric Reflectance

Wenzel Alban Jakob, Tizian Lucien Zeltner, Xin Tong

Realistic modeling of the bidirectional reflectance distribution function (BRDF) of scene objects is a vital prerequisite for any type of physically based rendering. In the last decades, the availability of databases containing real-world material measurem ...

ASSOC COMPUTING MACHINERY2020