Accelerated Wirtinger Flow: A fast algorithm for ptychography
This work provides a faster, parameter-free algorithm for ptychographic image reconstruction, benefiting computational imaging applications.
Accelerated Wirtinger Flow (AWF) combines Nesterov acceleration with Wirtinger gradient descent for ptychographic reconstruction, achieving faster convergence and higher image quality with less computation than classical methods, while being robust to noise and probe misalignment.
This paper presents a new algorithm, Accelerated Wirtinger Flow (AWF), for ptychographic image reconstruction from phaseless diffraction pattern measurements. AWF is based on combining Nesterov's acceleration approach with Wirtinger gradient descent. Theoretical results enable prespecification of all AWF algorithm parameters, with no need for computationally-expensive line searches and no need for manual parameter tuning. AWF is evaluated in the context of simulated X-ray ptychography, where we demonstrate fast convergence and low per-iteration computational complexity. We also show examples where AWF reaches higher image quality with less computation than classical algorithms. AWF is also shown to have robustness to noise and probe misalignment.