Plane-wave-illuminated macroscopic Fourier ptychography with a constant field of view

Macroscopic Fourier ptychography (MFP) is a computational imaging technique that integrates synthetic aperture with phase retrieval algorithms to achieve high-resolution (HR) imaging at long standoff distances. To acquire the required sub-aperture spectral information, MFP typically employs convergent spherical-wave illumination to form the object spectrum at the camera aperture plane. However, the inherent property of a convergent wave causes the imaging field of view (FOV) to shrink as the imaging distance increases, which greatly limits its applicability in long-distance scenarios. Here, we propose a plane-wave-illuminated macroscopic Fourier ptychography (PI-MFP) method to achieve FOV-constant HR imaging for diffuse reflective objects at different imaging distances. By incorporating the phase term of plane-wave illumination and the imaging-distance-related quadratic phase factor into the phase of the diffuse reflective object, we establish a dummy-object forward imaging model for plane-wave-illuminated MFP to enable HR amplitude reconstruction without forming the object spectrum at the aperture plane. The effectiveness of the dummy-object model was quantitatively verified at different imaging distances and object-field extents. Imaging results on resolution targets from both simulations and experiments demonstrate a 2.8-fold resolution enhancement, approaching the theoretical threefold value. Furthermore, experiments on a Quick Response code demonstrate that PI-MFP maintains a constant FOV across an approximately threefold range of imaging distances, while experiments on a 1-yuan banknote confirm its HR imaging capability for everyday objects. These results establish PI-MFP as a practical method for long-distance HR imaging with potential applications in remote sensing and security surveillance.