Indexed spectral images and confusion matrices of image 120514 . (A): Random-forest classified reference image. (B-D): Segmentations and confusion matrices obtained by different annotation approaches. In the confusion matrices, the numbers beside the tissue names indicate class sizes, and the tissues are sorted by size in descending order. Ward’s clustering in combination with the power metric achieves an Rand index of 0.83 and accuracy of 53.35% (data not shown).