Fig. 1
From: Novel accuracy test for multispectral imaging systems based on ΔE measurements

Illustration of the problem. The task is to infer the Δ E distribution of a color chart (here with 345 different color patches) from a small sample (here with 18 values). Δ E values are obtained by comparing the reference color spectra of the color patches with the corresponding spectra obtained from multispectral measurements