Adjustment of emissivities in radiation-based temperature measurement.
This is useful in cases where the emissivity is unknown during measurement: temperatures recorded at a certain emissivity (e.g. set to 1) can be converted to a new emissivity.
The project is developed and maintained by the Model experiments group at the Leibniz Institute for Crystal Growth (IKZ).
If you use this code in your research, please cite this repository:
A. Wintzer, K. Dadzis: github.com/nemocrys/emissivity-adjustment, https://doi.org/10.5281/zenodo.8202759.
This repository provides two ways for emissivity adjustment. In the top of the scripts the following values have to be set:
t1: the temperature that was measured (with wrong emissivity), in Kelvineps1: the emissivity that was set during measurement, a value between 0 and 1eps2: the new emissivity (for which the temperature shall be computed), a value between 0 and 1- the wavelength range of the measurement device:
l1: minimum wavelength, in meterl2: maximum wavelength, in meter
It is recommended to use the script spectral_radiance.py, because the computation is more accurate (even though it takes a little longer).
To change emissivity of complete images use convert_ir_image.py.
In the script spectral_radiance.py the integral of the spectral radiance function
is used to convert the measured temperature. The computation is performed as a fixed point iteration, it is most accurate.
The Wien approximation for the blackbody radiation spectrum
is accurate for short wavelength radiation and, thus, provides a simple way for adjustment of emissivities at high frequencies. It is faster but, in general, less accurate than the integration of the spectral radiance. It is implemented in wien_approximation.py.
This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 851768).
