Fourier ptychography for high space-bandwidth product microscopy

Fourier ptychography is a novel imaging technique with high space-bandwidth product (SBP) on the scale of gigapixel, and has been successfully applied for high-resolution and large field-of-view (FOV) microscopy, termed Fourier ptychographic microscopy (FPM). FPM utilizes a low-numerical-aperture objective lens to capture multiple large FOV but low-resolution images under angularly varying illumination, and uses phase-retrieval algorithms to reconstruct the sample's high-resolution amplitude and phase information. FPM is advantageous over conventional high SBP microscopy techniques in many aspects, including no mechanical scanning, computational acquisition of both amplitude and phase, extended depth of focus, long working distance, and high compatibility with current microscopes. In this paper, we review FPM with its principles, multiple techniques to improve its performance, and its various applications and extensions.