Fourier ptychography: current applications and future promises

Abstract

Traditional imaging systems exhibit a well-known trade-off between the resolution and the field of view of their captured images. Typical cameras and microscopes can either "zoom in" and image at high-resolution, or they can "zoom out" to see a larger area at lower resolution, but can rarely achieve both effects simultaneously. In this review, we present details about a relatively new procedure termed Fourier ptychography (FP), which addresses the above trade-off to produce gigapixel-scale images without requiring any moving parts. To accomplish this, FP captures multiple low-resolution, large field-of-view images and computationally combines them in the Fourier domain into a high-resolution, large field-of-view result. Here, we present details about the various implementations of FP and highlight its demonstrated advantages to date, such as aberration recovery, phase imaging, and 3D tomographic reconstruction, to name a few. After providing some basics about FP, we list important details for successful experimental implementation, discuss its relationship with other computational imaging techniques, and point to the latest advances in the field while highlighting persisting challenges.

Far‐Field Superresolution Imaging via Spatial Frequency Modulation

“…[ 47,49,168 ] But, to achieve superresolution microscopy, the introduction of evanescent waves becomes the key. [ 169,170 ] Evanescent fields occupy the near‐field region of dielectric waveguides due to the imaginary transverse wavevector. [ 171 ] The magnitude of the in‐plane wavevector can be tuned by the waveguide geometry and can thus provide the spatial frequency required to break the diffraction limit for SFS‐based new microscopy techniques.…”

Recent technical advances in whole slide imaging instrumentation

“…These include the structured illumination microscopy (SIM) and the Fourier ptychography microscopy (FTM). Detailed discussions on these methods themselves can be found in literature 47–52 . Wide FoV microscopy refers to a set of methods that enable millimeter sized FoV – far larger than conventional optical microscopy.…”

“…Detailed discussions on these methods themselves can be found in literature. [47][48][49][50][51][52] Wide FoV microscopy refers to a set of methods that enable millimeter sized FoV -far larger than conventional optical microscopy. Two methods reported for slide imaging are Talbot microscopy and holography (though holography requires unstained tissue).…”

Toward simple, generalizable neural networks with universal training for low-SWaP hybrid vision

“…By contrast, we focus on hybrid imaging in which optical processing conditions sensor measurements and an electronic neural network performs reconstruction [39][40][41]. Our work is also inspired by pytchography approaches in [10][11][12]. Two phase masks are used to capture the intensity measurements of the object on the sensor, which are then fed to a no-hidden-layer neural network.…”

“…These reconstructions generally involve solving an inverse problem and retrieving the phase from phase-less intensity measurements. The field has been an active area of research for several decades [5][6][7] and inverse solvers achieve impressive results with additional coded optics or optical scanning [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. More recently, deep neural networks, and specifically convolutional neural networks, enable single feed-forward, non-iterative reconstruction [22] and are capable of learning from the statistical information contained in a variety of systems, from speckle [23,24] to coded diffraction [25] patterns.…”