Phase retrieval algorithms typically involve iterative processes that aim to solve the phase problem by minimizing the difference between the measured intensity data and the intensity calculated from a guessed phase. Popular methods include the Gerchberg-Saxton algorithm, the Hybrid Input-Output (HIO) algorithm, and the Error Reduction (ER) algorithm. These methods use a combination of Fourier transforms and constraints in real and reciprocal spaces to iteratively refine the phase estimate.
