Embedded pupil function recovery for Fourier ptychographic microscopy

Abstract

Abstract:We develop and test a pupil function determination algorithm, termed embedded pupil function recovery (EPRY), which can be incorporated into the Fourier ptychographic microscopy (FPM) algorithm and recover both the Fourier spectrum of sample and the pupil function of imaging system simultaneously. This EPRY-FPM algorithm eliminates the requirement of the previous FPM algorithm for a priori knowledge of the aberration in the imaging system to reconstruct a high quality image. We experimentally demonstrate the effectiveness of this algorithm by reconstructing high resolution, large field-of-view images of biological samples. We also illustrate that the pupil function we retrieve can be used to study the spatially varying aberration of a large field-of-view imaging system. We believe that this algorithm adds more flexibility to FPM and can be a powerful tool for the characterization of an imaging system's aberration.

3D intensity and phase imaging from light field measurements in an LED array microscope

“…Our initial guess of the 2D transmittance function at the corresponding sample slice is then o Δz x; y ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi I Δz x; y p . We then improve the estimate for the sample's intensity and phase at each slice, as well as an estimate of the pupil function aberrations [40,[44][45][46], by an iterative Fourier ptychography (c) Reconstructions using our multislice method are compared to light field refocusing and physically changing the microscope focus. Diffraction effects severely blur the light field results, whereas our multislice method is able to recover the full diffraction-limited resolution with improved image contrast, while also removing out-of-focus blur.…”

“…Our system is built on a commercial microscope in which the illumination unit has been replaced by a programmable LED array. This simple, inexpensive hardware modification enables not only 4D light field capture [35,38], but also dark field [38,39], phase contrast [35,39], Fourier ptychography [23,24], and digital aberration removal [40].…”

Aperture-scanning Fourier ptychography for 3D refocusing and super-resolution macroscopic imaging

“…Our on-going efforts include 1) incorporating the pupil function correction functionality into the reported scheme [1,18,21,33,43,63], and 2) implementing the aperture-scanning scheme in a transmission electron microscope (TEM). We note that, in most commercially available TEM platforms, aperture scanning is a routine functionality for darkfield imaging [64].…”

“…Another source may be incorrect modeling of the aperture shape (we use a circular pupil in our FP reconstruction, while it should be an irregular pentagon corresponding to the Nikon photographic lens iris diaphragm). To reconstruct an improved-quality FP image, we can simultaneously recover both the high-resolution image and the irregular pupil function's shape [43].…”

Overlapped Fourier coding for optical aberration removal

“…We then constrain ψ After Fourier transforming ψ j into Ψ j , we are then ready to update our unaberrated sample spectrum estimate,Ŝ j . To remove the effects of aberrations, we adopt a strategy common to prior algorithms like ePIE [7] and EPRY [38] and effectively divide out the aberration function estimate A j from Ψ j :Ŝ…”