The document presents a new method for analyzing impact damage in composite materials using X-ray computed tomography. The method uses distance transforms and correlation maps to segment damage by ply and provide qualitative and quantitative damage metrics for each ply. It was shown to better represent the complex 3D morphology of impact damage compared to previous methods. The ply-by-ply damage separation allows understanding how damage evolves with increasing impact energy and improves understanding of damage failure modes. The new method can be applied to analyze impact damage in other laminated materials beyond polymer composites.