Work

A control variates technique for the null-collision Monte Carlo algorithms in radiative transfer

Year: 2026

Type: article

Abstract: We propose a control variates technique to reduce the variance of null-collision Monte Carlo algorithms used for solving the Radiative Transfer Equation (RTE) in highly heterogeneous media.The method complements the classical spatially partitioned overestimate approach by additionally recording the minimum absorption coefficient within each voxel during the preprocessing of the overestimate field.During path tracing, the attenuation due to this minimum absorption is evaluated analytically, while the residual part is handled by path-samplings.This analytical treatment significantly improves convergence particularly in strongly absorbing media such as the planetary atmospheres in infrared absorbing band.The mathematical equivalence between the original and control-variates estimators is demonstrated, and numerical applications for Earth’s and Titan’s atmospheres confirm the expected variance reduction.

Source: Journal of Quantitative Spectroscopy and Radiative Transfer

DOI: 10.1016/j.jqsrt.2026.110000

Authors: Zili He, Anthony Arfaux, Yaniss Nyffenegger-Péré, Nada Mourtaday