Phase retrieval is a mathematical process used to recover the phase information of a signal or image from its intensity measurements. In many applications, such as optics and computer vision, only the intensity of a wave can be directly measured, while the phase remains unknown. This phase information is crucial for accurately reconstructing the original signal. The challenge of phase retrieval arises because the relationship between intensity and phase is inherently nonlinear. Various algorithms, such as Gerchberg-Saxton and Fienup methods, have been developed to iteratively estimate the phase and improve the reconstruction. These techniques are essential in fields like X-ray imaging and electron microscopy.