Shape from Thermal Radiation:
Passive Ranging Using Multi-spectral LWIR Measurements

CVPR 2022

Nara Institute of Science and Technology (NAIST), Japan1 Ritsumeikan University, Japan2

*Equal contribution


Some result of our depth sensing method: Shape from Thermal Radiation.



In this paper, we propose a new cue of depth sensing using thermal radiation. Our method realizes passive, texture independent, far range, and dark scene applicability, which can broaden the depth sensing subjects. A key observation is that thermal radiation is attenuated by the air and is wavelength dependent. By modeling the wavelength-dependent attenuation by the air and building a multi-spectral LWIR measurement system, we can jointly estimate the depth, temperature, and emissivity of the target. We analytically show the capability of the thermal radiation cue and show the effectiveness of the method in real-world scenes using an imaging system with a few bandpass filters.



Overview of the shape from thermal radiation. Our method jointly estimates the depth, temperature, and emissivity images from multi-spectral LWIR images. A key observation is that thermal radiation from the target object is attenuated through the air and is wavelength dependent. When the attenuation spectrum (i.e. extinction coefficient) of the air is known, we can estimate the depth, temperature and emissivity.



LWIR measurement observation is performed fully passively(i.e. no light source needed). Additionaly, proposal method is texture-less and far range capable because the depth is estimated based on LWIR light attenuation. So, our method overcomes many weakness of conventional methods.