Speckle Reduction for Fourier Ptychographic Reconstruction Using Gamma-Correction and Reshaped Wirtinger Flow Optimization

Fourier ptychography is a newly reported computational imaging technique, which is used for long-distance, sub-diffraction imaging recently. Compared to conventional Fourier ptychographic microscopy, there is pronounced laser speckle noise in captured images. In this work, a new framework is proposed to suppress speckle noise and reconstruct the high-resolution image for diffuse object. We introduce a random phase to simulate the effects of rough surface during imaging process, and then recover the high-resolution spectrum following two steps: the first is to promote the noisy captured images using Gamma-correction, and the second step is to recover the Fourier spectrum using reshaped Wirtinger flow optimization. Experiments on both simulation and real data demonstrate that the proposed method incorporates speckle noise reduction into reconstruction process, which can achieve better results on both visual and quantitative metrics compared to previous work.