UnMix -NeRF: Spectral Unmixing Meets Neural Radiance Fields

Fabian Perez1, Sara Rojas2, Carlos Hinojosa2, Hoover Rueda-Chacón1, Bernard Ghanem2,
1Universidad Industrial de Santander; 2King Abdullah University of Science and Technology (KAUST)
Paper Supplementary Code Data
Introduction Image

TL;DR: We propose UnMix-NeRF, the first method integrating spectral unmixing into NeRF, enabling hyperspectral view synthesis, accurate unsupervised material segmentation, and intuitive material-based scene editing, significantly outperforming existing methods.


Abstract

Neural Radiance Field (NeRF)-based segmentation methods focus on object semantics and rely solely on RGB data, lacking intrinsic material properties. This limitation restricts accurate material perception, which is crucial for robotics, augmented reality, simulation, and other applications. We introduce UnMix-NeRF, a framework that integrates spectral unmixing into NeRF, enabling joint hyperspectral novel view synthesis and unsupervised material segmentation. Our method models spectral reflectance via diffuse and specular components, where a learned dictionary of global endmembers represents pure material signatures, and per-point abundances capture their distribution. For material segmentation, we use spectral signature predictions along learned endmembers, allowing unsupervised material clustering. Additionally, UnMix-NeRF enables scene editing by modifying learned endmember dictionaries for flexible material-based appearance manipulation. Extensive experiments validate our approach, demonstrating superior spectral reconstruction and material segmentation to existing methods. The associated data and code for reproduction will be made publicly available.


Hotdog Scene

RGB

Unsupervised Material Segmentation

Scene Editing


Spectral Reflectances

450 nm

500 nm

550 nm

600 nm

650 nm


Visualization of Learned Material Abundances

Specular Reflectances

Endmembers Learning During Training
Endmember Learning