Speckle Reduction for Long Distance Fourier Ptychography Using Truncated Amplitude Flow and Filtering

Abstract

Fourier Ptychography (FP) is a new method for long-distance, sub-diffraction imaging. However, due to the coherence of laser-illumination and the scattering of the objects' surface, there will be obvious laser speckle noise in measured images. In this work, we reconstruct the high-resolution image following two steps: the first step is to recover the Fourier spectrum using truncated amplitude flow algorithm, and the second step is to enhance the noisy recovered images using denoisers during reconstruction. It's demonstrated that this method can effectively suppress speckle noise, improve PSNR about 7dB and improve SSIM about 0.2 compared with other algorithms.