Efficient Synthetic Aperture for Phaseless Fourier Ptychographic Microscopy with Hybrid Coherent and Incoherent Illumination

Fourier ptychographic microscopy (FPM) is a computational high-throughput technique for high-resolution and wide field-of-view (FOV) imaging applications such as cell biology, medicine screening, and digital pathology. By integrating angle-varied illumination, iteration phase retrieval, and synthetic aperture, it achieves a significantly enhanced imaging resolution beyond the diffraction limit of the objective lens while retaining its original large FOV without any mechanical movement. However, sufficient data redundancy is a prerequisite for the convergence of the iteration algorithm, which in turn requires dozens or even hundreds of raw images to get a decent resolution, leaving ample room for further improvement. In this paper, an efficient synthetic aperture scheme for FPM is proposed, termed ESA-FPM. It employs both coherent and incoherent illuminations to maximize the efficiency of data utilization and achieve high spatial-bandwidth product (SBP) reconstruction with few acquisitions. The data redundancy requirements are further analyzed, suggesting that ESA-FPM reaches imaging resolution of 3NAobj$3NA_{\rm obj}$ using only seven images. The experiment with USAF target demonstrates that ESA-FPM achieves theoretical resolution with only 1.6% of the data of conventional FPM. A customized miniaturized ESA-FPM system with a high-numerical-aperture, low-magnification objective lens, and a high-brightness LED array is built, demonstrating its potential for biomedical and pathological applications.

Automated summary

Fourier ptychographic microscopy (FPM) is a computational high-throughput technique that achieves high-resolution and wide field-of-view (FOV) imaging. This paper proposes an efficient synthetic aperture scheme for FPM, called ESA-FPM, which utilizes both coherent and incoherent illuminations to maximize data utilization and achieve high-resolution reconstruction with few acquisitions. The experiment demonstrates that ESA-FPM achieves theoretical resolution with only 1.6% of the data of conventional FPM.