Implementations disclosed describe a method of obtaining a first image of a sample using a first light, wherein the sample has been subjected to a processing operation associated with a change of a thickness of the sample. The method further includes weighing the sample to obtain a first mass of the sample. The method further includes determining, based at least in part on the first image of the sample and the first mass of the sample, one or more properties of the sample, such as the change of a thickness of the sample, a change of an refractive index of the sample, and/or a change of an optical density of the sample a distribution of the change of the thickness of the sample.