Fourier ptychography

Fourier ptychography is a computational imaging technique based on optical microscopy that consists in the synthesis of a wider numerical aperture from a set of full-field images acquired at various coherent illumination angles,[1] resulting in increased resolution compared to a conventional microscope.

[3] Like real space ptychography, the solution of the phase problem relies on the same mathematical shift invariance constraint, except in Fourier ptychography it is the diffraction pattern in the back focal plane that is moving with respect to the back-focal plane aperture.

[7] Variants of these algorithms allow for simultaneous reconstruction of the pupil function of an optical system,[8] allowing for the correction of the aberrations of the microscope objective, and diffraction tomography[9] which permits the 3D reconstruction of thin sample objects without requiring the angular sample scanning needed for CT scans.

A major advantage of Fourier ptychography is the ability to use a microscope objective with a lower numerical aperture without sacrificing the resolution.

However, the two techniques are both based on the determination of the angular spectrum of the object through a phase retrieval procedure,[11] and inherently reconstruct the same information.