Far-Field Synthetic Aperture Imaging via Fourier Ptychography with Quasi-Plane Wave Illumination

Fourier ptychography (FP) technique is a promising super-resolution tool in noninterferometric synthetic aperture research thanks to its unique capabilities for circumventing the physical limitation of space bandwidth product. However, FP imaging in the long-range scenario suffers from field-of-view (FOV) attenuation due to spherical-wave imaging characteristics, and the speckle noise of most targets further restricts the FP's application in far-field detection. Herein, a remote FP (R-FP) technique is proposed to address the issues by combining the idea of quasi-plane wave illumination and the total variation-guided filtering (TVGF) method. Compared with conventional macroscopic Fourier ptychographic imaging, R-FP overcomes the contradiction between FOV and detection range and mitigates the effect of speckle noise by utilizing the TVGF method, as demonstrated by high-resolution imaging of various targets (including United States Air Force (USAF) resolution chart, spade poker, and fingerprint). In particular, the long-range FP capability of the proposed approach is demonstrated by the synthetic aperture imaging of a King poker card at 12 m away. To the best of the authors' knowledge, R-FP achieves the farthest detection range of macroscopic Fourier ptychographic imaging up to date, demonstrating its potential for application in far-field detection.

Automated summary

The remote Fourier ptychography (R-FP) technique is a promising super-resolution tool in non-interferometric synthetic aperture research. It overcomes the limitations of field-of-view attenuation and speckle noise in long-range FP imaging by utilizing quasi-plane wave illumination and the TVGF method. R-FP achieves the farthest detection range of macroscopic Fourier ptychographic imaging to date, showing potential for application in far-field detection.