A fine example is the development of a camera system that quantitatively determines the age of bruises. The motivation for this development is to create an extra tool to identify child abuse. The system uses a hyperspectral snapshot camera to measure the fraction of bilirubin and hemoglobin. A bruise turns blue because of the hemoglobin in the bruise. Gradually, over a period of days, that hemoglobin breaks down. The resulting waste bilirubin turns the bruise yellow. The ratio in measured quantity between those two substances determine the age of a bruise.