Comparison of phase unwrapping algorithms for living cell's interference pattern

A multiphase microscopic interference system is designed to measure the height of cell which is important to the research of collective cell migration in physiology and medicine. This system can quantitatively measure cell height across a living monolayer without knowing the refractive index of cells. For the interference pattern, because the phases are all wrapped between-π to π, it is necessary to get the real phase through phase unwrapping, a method to restore the wrapped phase data of the object by using numerical calculations. Three representative algorithms are selected to unwrap the interference pattern of cells: branch-cut method, quality-guided method and network method. Although each of them can restore the phase, their performances are obviously different. We compare these methods and find that branch-cut method needs the smallest execution time and can obtain good unwrapped patterns when noises are not serious.