Quantifying shapes of nanoparticles using modified circularity and ellipticity measures

We propose using a new circularity measure and a new ellipticity measure. Observing an example of hematite (α-Fe₂O₃) nanoparticles, we compared and discussed the new circularity measure with the standard one. It has been shown that the new measure gives better results when working with low-quality or low-resolution images. Using the same images, a modified ellipticity measure has also been discussed. We analysed the problems arising from computing elongation of a shape and we have shown that the standard approach to compute elongation is not appropriate for some particles. We presented the application of the modified approach to solve this problem.