Figure 2
From: Multi-level contrast filtering in image difference metrics
BFD ellipses on the coordinates JG of the OSA-UCS space. The ellipses show a general regularity that suggests the hue-independence hypothesis and consequently a simple ellipsoidal color difference formula [5, 21], which is based on all the existing data (COM dataset [14]). The next step towards the Euclidean formula [21] is the logarithmic compression of the chroma (Figure 3).