Fig. 17
From: Tensor decomposition for painting analysis. Part 1: pigment characterization

Matches of the endmembers with the pigments in the ENST dataset, visualized as a bubble chart. The x-coordinate represents the spectral angle in radians computed on reflectance spectra between endmembers and reference dataset, while the y-coordinate is the spectral angle in radians computed on the first derivative. The diameter of the bubble is proportional with the spectral correlation between the reflectance spectra. Bigger bubbles in the bottom left indicate a higher confidence of the match