Extended Data Fig. 6: HADAR estimation theory for multi-material library.
a, Sample incident spectra of five materials generated by Monte Carlo simulations. T = 60 °C, T0 = 20 °C and V0 = 0.5. b, Minimum statistical distance of each material. Spectra of silica and paint have non-trivial features that are distinct from other materials in the library. Statistical distance larger than 1 (dashed line) consistently indicates that silica and paint are identifiable. Note that aluminium is similar to human skin under TeX degeneracy and non-identifiable, as discussed in Fig. 3, even though with the same temperature its spectrum is much weaker than human skin. Emissivity of human skin was approximated as a constant 0.95. Other emissivity profiles were drawn from the NASA JPL ECOSTRESS spectral library. This figure intuitively shows that HADAR identifiability based on semantic/statistical distance is an effective figure of merit to describe identifiability. For more details on generalizing HADAR estimation theory to several materials, see section SII.B of the Supplementary Information.
