Structured Illumination Imaging Research Articles

Toward robust super-resolution imaging: A low-rank approximation approach for pattern-illuminated Fourier ptychography

Pattern-illuminated Fourier ptychography (piFP) is an elegant combination of structured illumination imaging and a Fourier ptychographic algorithm with the ability to image beyond the diffraction limit of the employed optics. Artifact-free piFP super-resolution reconstruction requires a high level of stability in the illumination pattern. However, unpredictable pattern variation occurs in the presence of environment perturbation, intensity fluctuation, and pointing instability at the source, leading to declines in image reconstruction quality. To address this issue, we present an efficient and robust piFP algorithm based on low-rank approximation (LRA-piFP), which relaxes the requirement for the stability of illumination patterns. This LRA-piFP method can model frame-wise pattern variation during a full scan, thus improve the reconstruction quality significantly. We take numerical simulations and proof-of-principle experiments with both long-range imaging and microscopy for demonstrations. Results show that the LRA-piFP method can handle different kinds of pattern variation and outperforms other state-of-the-art techniques in terms of reconstruction quality and resolution improvement. Our method provides effective experimental robustness to piFP with a natural algorithmic extension, paving the way for its application in both macroscopic and microscopic imaging.

Analysis of influential factors of image reconstruction quality in structured illumination imaging and its application in laser microprocessing.

Due to the huge demand for higher resolution and stable imaging from fluorescent labeling biological systems and life systems, there has been much research and development of structured light illumination imaging (SIM). Despite this, further investigating the possible applications of SIM in other fields is still meaningful. In this paper, super-resolution observation of non-fluorescent samples by a SIM system under reflective illumination is analyzed. The simulation of SIM imaging and image reconstruction is carried out by using an open-source program, and the influences of the structural parameters of the illumination light (fringe direction, phase, and intensity uniformity of the cosine structured light), the optical parameters of the imaging system (selection of the optical transfer function) and the anti-vibration characteristics of the platform on the super-resolution imaging effect are studied. Finally, by optimizing the above influential factors according to simulation results, successful application of SIM in laser processing process monitoring is demonstrated in the experiment. We believe that our research results will provide some reference for the application of SIM in other similar scenarios.

Abstract P3-08-06: Monitoring Lymphovascular Invasion and Tumor Growth of Inflammatory Breast Cancer in a Murine Lymphatic Reporter Window Chamber Model

Abstract Background: Lymphovascular invasion (LVI) is a major route of metastatic dissemination and recent studies indicate its value as an independent prognostic indicator for advanced breast, colorectal, squamous cell, prostate, brain cancers. LVI is a clinicopathological hallmark of inflammatory breast cancer (IBC), an understudied and most lethal breast cancer. IBC is often misdiagnosed due to an absence of a solid mass and its unique presentation of diffuse tumor cell clusters/emboli in the dermal lymphatics. Widely used mammary tumor implantation models coupled with bioluminescence or fluorescence imaging to monitor tumor growth kinetics are ineffective for evaluating spatial and temporal changes in growth and migration patterns of individual tumor cells and clusters within their microenvironmental context. The goal of this study was to develop a murine model to simulate the unique clinicopathological features of IBC patients and to assess both qualitatively and quantitatively local tumor growth, motility, and LVI. Methods: To specifically facilitate visualization of lymphatic and endothelial vessels along with tumor-vessel interactions, we generated a transgenic nude mice model (ProxTom RFP Nu/Nu) wherein, the mice exhibit red, fluorescent lymphatics [tdTomato fluorophore under control of a Prox1 promoter, which encodes a transcription factor (prospero-related homeobox 1) necessary for the formation and maintenance of lymphatic vessels]. Next, we employed a surgical technique, wherein a window chamber is placed on the dorsal skinfold of mice, which allows for microscopic examination of implanted tumor cells and ability to track dynamic changes of the tumor in its local microenvironment from the time of implantation up to 10 days. Patient-derived IBC or PDX stably transfected to express green, red fluorescent and/or dual tagged with luciferase reporters were transplanted in mice bearing window chambers. Intravital fluorescence microscopy and IVIS imaging were used to serially quantify local tumor growth, motility, length density of lymph and blood vessels, and degree of tumor cell lymphatic invasion over 0-140h. Results: Multichannel optical imaging of the window chamber in the ProxTom RFP Nu/Nu mice demonstrated co-localization of IBC tumor cells and lymphatics. Diffuse tumor cells were observed along regions of lymphatic vessels both proximal and distal to the primary tumor site. However, measurement of blood and lymph vessel density showed no significant change over time. Next, these datasets were used for quantitative analysis by setting the tumor cell channel (GFP) at a threshold to count any clusters greater than 50 pixels2 (~0.0013mm2) and with greater than the mean + 2 standard deviations of the background signal while avoiding noise/artifacts from very small regions (<~0.001mm2). This allowed for computation of the total tumor area including average area of each cluster. In addition, the area moment, which describes the basic directional growth pattern of the tumor cells, was quantified by multiplying a cluster distance from the center of mass by its area. Conclusions: A key novel finding from structured illumination imaging data was the observation of LVI occurring early, similar with the clinical presentation in IBC patients. This model was able to effectively track tumor cluster migration. This approach of short-term longitudinal imaging time frame in studying transient or dynamic events of diffuse, collectively migrating tumor cells in the local environment and quantitative analysis of the tumor area, motility and vessel characteristics is an innovation that can be used to investigate other cancer cell types exhibiting LVI. Funding in part by DoD W81XWH-17-1-0297; W81XWH201053 (GRD); ACS Mission Boost grant MBG-20-141-01 (GRD) and NIH grant P30-CA014236 (Imaging Core/GMP) Citation Format: Gayathri R Devi, Dorababu Sannareddy, Alexandra Bennion, Ashlyn Rickard, Douglas C Rouse, Mark W Dewhirst, Gregory M Palmer. Monitoring Lymphovascular Invasion and Tumor Growth of Inflammatory Breast Cancer in a Murine Lymphatic Reporter Window Chamber Model [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-08-06.

Using an acousto-optic modulator as a fast spatial light modulator.

High-speed spatial light modulators (SLM) are crucial components for free-space communication and structured illumination imaging. Current approaches for dynamical spatial mode generation, such as liquid crystal SLMs or digital micromirror devices, are limited to a maximum pattern refresh rate of 10 kHz and have a low damage threshold. We demonstrate that arbitrary spatial profiles in a laser pulse can be generated by mapping the temporal radio-frequency (RF) waveform sent to an acousto-optic modulator (AOM) onto the optical field. We find that the fidelity of the SLM performance can be improved through numerical optimization of the RF waveform to overcome the nonlinear effect of AOM. An AOM can thus be used as a 1-dimensional SLM, a technique we call acousto-optic spatial light modulator (AO-SLM), which has 50 µm pixel pitch, over 1 MHz update rate, and high damage threshold. We simulate the application of AO-SLM to single-pixel imaging, which can reconstruct a 32×32 pixel complex object at a rate of 11.6 kHz with 98% fidelity.

Increased Expression of LASI lncRNA Regulates the Cigarette Smoke and COPD Associated Airway Inflammation and Mucous Cell Hyperplasia.

Research ImpactCigarette smoke (CS) exposure is strongly associated with chronic obstructive pulmonary disease (COPD). In respiratory airways, CS exposure disrupts airway barrier functions, mucous/phlegm production, and basic immune responses of airway epithelial cells. Based on our recent identification of a specific immunomodulatory long noncoding RNA (lncRNA), we investigated its role in CS-induced responses in bronchial airways of cynomolgus macaque model of CS-induced COPD and in former smokers with and without COPD. The lncRNA was significantly upregulated in CS-induced macaque airways and in COPD airways that exhibited higher mucus expression and goblet cell hyperplasia. Experimental models of cells derived from COPD subjects recapitulated the augmented inflammation and mucus expression following the smoke challenge. Blocking of lncRNA expression in cell culture setting suppressed the smoke-induced and COPD-associated dysregulated mucoinflammatory response suggesting that this airway specific immunomodulatory lncRNA may represent a novel target to mitigate the smoke-mediated inflammation and mucus hyperexpression.RationaleIn conducting airways, CS disrupts airway epithelial functions, mucociliary clearances, and innate immune responses that are primarily orchestrated by human bronchial epithelial cells (HBECs). Mucus hypersecretion and dysregulated immune response are the hallmarks of chronic bronchitis (CB) that is often exacerbated by CS. Notably, we recently identified a long noncoding RNA (lncRNA) antisense to ICAM-1 (LASI) that mediates airway epithelial responses.ObjectiveTo investigate the role of LASI lncRNA in CS-induced airway inflammation and mucin hyperexpression in an animal model of COPD, and in HBECs and lung tissues from former smokers with and without COPD. To interrogate LASI lncRNA role in CS-mediated airway mucoinflammatory responses by targeted gene editing.MethodsSmall airway tissue sections from cynomolgus macaques exposed to long-term mainstream CS, and those from former smokers with and without COPD were analyzed. The structured-illumination imaging, RNA fluorescence in-situ hybridization (FISH), and qRT-PCR were used to characterize lncRNA expression and the expression of inflammatory factors and airway mucins in a cell culture model of CS extract (CSE) exposure using HBECs from COPD (CHBEs) in comparison with cells from normal control (NHBEs) subjects. The protein levels of mucin MUC5AC, and inflammatory factors ICAM-1, and IL-6 were determined using specific ELISAs. RNA silencing was used to block LASI lncRNA expression and lentivirus encoding LASI lncRNA was used to achieve LASI overexpression (LASI-OE).ResultsCompared to controls, LASI lncRNA was upregulated in CS-exposed macaques and in COPD smoker airways, correlating with mucus hyperexpression and mucus cell hyperplasia in severe COPD airways. At baseline, the unstimulated CHBEs showed increased LASI lncRNA expression with higher expression of secretory mucin MUC5AC, and inflammatory factors, ICAM-1, and IL-6 compared to NHBEs. CSE exposure of CHBEs resulted in augmented inflammation and mucus expression compared to controls. While RNA silencing-mediated LASI knockdown suppressed the mucoinflammatory response, cells overexpressing LASI lncRNA showed elevated mRNA levels of inflammatory factors.ConclusionsAltogether, LASI lncRNA may represent a novel target to control the smoke-mediated dysregulation in airway responses and COPD exacerbations.

Optical Microscopy Systems for the Detection of Unlabeled Nanoparticles.

Label-free detection of nanoparticles is essential for a thorough evaluation of their cellular effects. In particular, nanoparticles intended for medical applications must be carefully analyzed in terms of their interactions with cells, tissues, and organs. Since the labeling causes a strong change in the physicochemical properties and thus also alters the interactions of the particles with the surrounding tissue, the use of fluorescently labeled particles is inadequate to characterize the effects of unlabeled particles. Further, labeling may affect cellular uptake and biocompatibility of nanoparticles. Thus, label-free techniques have been recently developed and implemented to ensure a reliable characterization of nanoparticles.This review provides an overview of frequently used label-free visualization techniques and highlights recent studies on the development and usage of microscopy systems based on reflectance, darkfield, differential interference contrast, optical coherence, photothermal, holographic, photoacoustic, total internal reflection, surface plasmon resonance, Rayleigh light scattering, hyperspectral and reflectance structured illumination imaging. Using these imaging modalities, there is a strong enhancement in the reliability of experiments concerning cellular uptake and biocompatibility of nanoparticles, which is crucial for preclinical evaluations and future medical applications.

Deep learning-based single-shot structured illumination microscopy

We report a deep learning-based structured illumination microscopy (SIM) method, which can reconstruct a super-resolution (SR) image using only one frame structured illumination image. Generative adversative networks (GANs) and deformation of U-Net (DU-Net) are employed to perform the task. GANs are trained to generate other structured illumination images by feeding a single structured illumination image, and DU-Net is trained to reconstruct the super-resolution image. The results of experiments and simulations demonstrate that the SR image could be reconstructed from one frame structured illumination image. Importantly, it can greatly reduce phototoxicity and photobleaching.

Understanding and correcting wavenumber error in interference pattern structured illumination imaging.

The impacts of uncertainty in mirror movements in mechanically scanned interference pattern structured illumination imaging (IPSII) are discussed. It is shown that uncertainty in IPSII mirror movements causes errors in both the phase and amplitude of the Fourier transform of the resulting imaging. Finally, we demonstrate that iterative phase retrieval algorithms can improve the quality of IPSII images by correcting the phase errors caused by mirror movement uncertainties.

Fourier-basis structured illumination imaging with an array of integrated optical phased arrays.

Active imaging and structured illumination originated in "bulk" optical systems: free-space beams controlled with lenses, spatial light modulators, gratings, and mirrors to structure the optical diffraction and direct the beams onto the target. Recently, optical phased arrays have been developed with the goal of replacing traditional bulk active imaging systems with integrated optical systems. In this paper, we demonstrate the first array of optical phased arrays forming a composite aperture. This composite aperture is used to implement a Fourier-based structured-illumination imaging system, where moving fringe patterns are projected on a target and a single integrating detector is used to reconstruct the spatial structure of the target from the time variation of the back-scattered light. We experimentally demonstrate proof-of-concept Fourier-basis imaging in 1D using a six-element array of optical phased arrays, which interfere pairwise to sample up to 11 different spatial Fourier components, and reconstruct a 1D delta-function target. This concept addresses a key complexity constraint in scaling up integrated photonic apertures by requiring only N elements in a sparse array to produce an image with N2 resolvable spots.

Tilt illumination for structured illumination imaging

To achieve super-resolution imaging, the information in higher frequency of the observed sample is collected by illuminating with a structure beam for a limited optical transfer function. In this paper, tilt illumination mode is introduced to structured illumination microscopy (SIM) for enhancing lateral resolution. More sample spectrum more than traditional SIM, can be obtained by detector. Thus, SIM with tilt illumination can be improved at the aspect of lateral imaging resolution.

Computational imaging with an extended field of view

The recorded field of view of any digital imaging system is limited by the physical size of the sensor array. While it is a common knowledge that the image field exists beyond the boundaries of the sensor array, there is generally no way to measure it unless the imaging system (or the object) is translated laterally. We propose a single-shot computational imaging system with a multiple-point impulse response that is able to effectively increase the physical size of the sensor array. The image recorded on the array sensor is not visually meaningful but can be used to recover the image field beyond the native sensor boundary via a sparsity based iterative algorithm, as we demonstrate in this work. The system concept can be considered analogous to structured illumination imaging; however, the structuring is performed here in the Fourier space in order to recover an extended image field. The effective increase in the sensor size depends on the extent of the impulses in the engineered multiple point impulse response. The achievable sensor size extension is therefore limited by the resolution of the phase mask that is introduced in the Fourier plane of the imaging system. We present a simulation study where the individual impulses in the designed impulse response extend over the original array sensor size, thereby doubling the effective sensor dimensions (a four times increase in the number of pixels) without affecting the image resolution. Both binary and gray-scale objects have been considered in our study in order to illustrate that the quality of the extended field of view image depends on the sparsity of the object under consideration. The concept of extended field of view computational imaging as presented here may find a number of practical applications.

Deep learning based one-shot optically-sectioned structured illumination microscopy for surface measurement.

Optically-sectioned structured illumination microscopy (OS-SIM) is broadly used for biological imaging and engineering surface measurement owing to its simple, low-cost, scanning-free experimental setup and excellent optical sectioning capability. However, the efficiency of current optically-sectioned methods in OS-SIM is yet limited for surface measurement because a set of wide-field images under uniform or structured illumination are needed to derive an optical section at each scanning height. In this paper, a deep-learning-based one-shot optically-sectioned method, called Deep-OS-SIM, is proposed to improve the efficiency of OS-SIM for surface measurement. Specifically, we develop a convolutional neural network (CNN) to learn the statistical invariance of optical sectioning across structured illumination images. By taking full advantage of the high entropy properties of structured illumination images to train the CNN, fast convergence and low training error are achieved in our method even for low-textured surfaces. The well-trained CNN is then applied to a plane mirror for testing, demonstrating the ability of the method to reconstruct high-quality optical sectioning from only one instead of two or three raw structured illumination frames. Further measurement experiments on a standard step and milled surface show that the proposed method has similar accuracy to OS-SIM techniques but with higher imaging speed.

Single-shot structured-light-field three-dimensional imaging.

This Letter reports an approach to single-shot three-dimensional (3D) imaging that is combining structured illumination and light-field imaging. The sinusoidal distribution of the radiance in the structured-light field can be processed and transformed to compute the angular variance of the local radiance difference. The angular variance across the depth range exhibits a single-peak distribution trend that can be used to obtain the unambiguous depth. The phase computation that generally requires the acquisition of multi-frame phase-shifting images is no longer mandatory, thus enabling single-shot structured-light-field 3D imaging. The proposed approach was experimentally demonstrated through a dynamic scene.

Specific Labeling of Mitochondrial Nucleoids for Time-lapse Structured Illumination Microscopy.

Mitochondrial nucleoids are compact particles formed by mitochondrial DNA molecules coated with proteins. Mitochondrial DNA encodes tRNAs, rRNAs, and several essential mitochondrial polypeptides. Mitochondrial nucleoids divide and distribute within the dynamic mitochondrial network that undergoes fission/fusion and other morphological changes. High resolution live fluorescence microscopy is a straightforward technique to characterize a nucleoid's position and motion. For this technique, nucleoids are commonly labeled through fluorescent tags of their protein components, namely transcription factor a (TFAM). However, this strategy needs overexpression of a fluorescent protein-tagged construct, which may cause artifacts (reported for TFAM), and is not feasible in many cases. Organic DNA-binding dyes do not have these disadvantages. However, they always show staining of both nuclear and mitochondrial DNAs, thus lacking specificity to mitochondrial nucleoids. By taking into account the physico-chemical properties of such dyes, we selected a nucleic acid gel stain (SYBR Gold) and achieved preferential labeling of mitochondrial nucleoids in live cells. Properties of the dye, particularly its high brightness upon binding to DNA, permit subsequent quantification of mitochondrial nucleoid motion using time series of super-resolution structured illumination images.

Quadrature Multiplexed Structured Illumination Imaging

Higher dimensional optical imaging has seen remarkable growth in the past decade. As a representative method, multiplexed structured illumination (MSI) has been widely introduced for its ultra-high resolution of high-dimensional information. In this letter, an imaging framework for recovering higher dimensional image data, which terms quadrature multiplexed structured illumination (QMSI), is proposed and demonstrated. QMSI incorporates the illumination pattern spatial phase information as a new parameter into the encoding process. This strategy can double the frequency spectrum utilization without any overhead compared to MSI, which means it can double the image sequence depth or image spatial resolution. As a proof of concept, we demonstrate the performance of QMSI by experiments on multispectral imaging.

Structured illumination imaging with quasi-periodic patterns.

Structured illumination microscopy (SIM) is a well-established method for optical sectioning and super-resolution. The core of structured illumination is using a periodic pattern to excite image signals. This work reports a method for estimating minor pattern distortions from the raw image data and correcting these distortions during SIM image processing. The method was tested with both simulated and experimental image data from two-photon Bessel light-sheet SIM. The results proves the method is effective in challenging situations, where strong scattering background exists, signal-to-noise ratio (SNR) is low and the sample structure is sparse. Experimental results demonstrate restoring synaptic structures in deep brain tissue, despite the presence of strong light scattering and tissue-induced SIM pattern distortion.

Reflectance structured illumination imaging of internalized cerium oxide nanoparticles modulating dose-dependent reactive oxygen species in breast cancer cells

Cerium oxide nanoparticles have been shown to sensitize cancer cells to radiation damage. Their unique redox properties confer excellent therapeutic potential by augmenting radiation dose with reactive oxygen species mediating bystander effects. Owing to its metallic properties, cerium oxide nanoparticles can be visualized inside cells using reflected light and optical sectioning. This can be advantageous in settings requiring none or minimal sample preparation and modification. We investigated the use of reflectance imaging for the detection of unmodified nanoceria in MDA MB231 breast cancer cells along with differential interference contrast imaging and fluorescent nuclear labeling. We also performed studies to evaluate the uptake capability, cellular toxicity and redox properties of nanocaria in these cells. Our results demonstrate that reflectance structured illumination imaging can effectively localize cerium oxide nanoparticles in breast cancer cells, and when combining with differential interference contrast and fluorescent cell label imaging, effective compartmental localization of the nanoparticles can be achieved. The total number of cells taking up the nanoparticles and the amount of nanoparticle uptake increased significantly in proportion to the dose, with no adverse effects on cell survival. Moreover, significant reduction in reactive oxygen species was also observed in proportion to increasing nanoceria concentrations attesting to its ability to modulate oxidative stress. In conclusion, this work serves as a pre-clinical scientific evaluation of the effective use of reflectance structured illumination imaging of cerium oxide nanoparticles in breast cancer cells and the safe use of these nanoparticles in MDA MB231 cells for further therapeutic applications.

PS1168 CHROMATIN TOPOLOGY AND THREE‐DIMENSIONAL ORGANIZATION OF CHROMOSOME TERRITORIES 9 AND 22 IN CD34+ BONE MARROW CELLS FROM CHRONIC MYELOID LEUKEMIA PATIENTS

Background:During interphase, chromosomes occupy a limited space within the nucleus, referred to as chromosome territory (CT). The non‐random CT's spatial organization in the nucleus contributes to determining the outcome of chromosomal translocations (t). Comparative analysis of the spatial arrangement of t‐partners and their frequency suggest that this chromosome aberration occurs preferentially among proximally positioned genome regions. The consistence appearance of t(9;22) in hematopoietic stem cells, apart from being etiological factor for chronic myeloid leukemia (CML), is a clear example of what is considered a non‐random chromosome aberration. Besides, the CT's spatial distribution is regulated by epigenetic factors such as post‐translational histone modifications. These modifications are also directly related to the chromatin topology in these CTs, which is relevant since a chromatin misconfiguration has been related to the susceptibility to generate mutations and translocations.Aims:‐ Determine the 3D arrangement of interphase CTs 9 and 22 and BCR‐ABL genes in CD34+ bone marrow (BM) cells from CML patients at the time of diagnosis (CML RxDx) and patients with complete response (CML CR) compared to healthy donors’ CD34+ mobilized bone marrow cells (MBM) and peripheral blood mononuclear cells (PBMC).‐ Map and quantify the distribution of the histone modifications H3K27me3 and H3K9ac across CTs 9 and 22 in our study population.Methods:The study population consisted of 5 BM from CML RxDx and CML CR patients, 5 MBM and PBMC from healthy donors. CD34+ hematopoietic cells were isolated and subsequently processed for 3D‐FISH and 3D immuno‐FISH. Super‐resolution imaging was performed by 3D structured illumination microscopy (SIM) and images reconstructed and analysed using Imaris program (Bitplane).Results:We found that nuclear volumes were significantly larger in CD34 + cells from MBM and CML patients compared to PBMC controls. The absolute CTs volume analysis shows a major volume of CT9 compared to CT22. To determine the distance between BA genes and their CTs we calculated the nearest distance between the mass center of CT9 and CT22. The shorter distance was between de CML RxDx cells since the translocation presence. When we compare the samples without t(9;22), the shorter distances were observed between BA from MBM and CML CR cells compared to PBMC samples. After normalizing the distance between the CTs and BA genes against the radius of the nucleus. We observed that the location of CT22 tended towards the center, whereas that of CT9 towards the nuclear periphery. Meanwhile BA genes were located closer to the nuclear center than the respective CTs’ geometrical center. We have mapped relevant histone modifications like H3K9ac and H3K27me3 across CT9 and 22 using 3D immuno‐FISH. The enrichment of H3K27me3 seems to be significantly decreased in CT22 from samples of CML CR cells.Summary/Conclusion:The consistent appearance of specific chromosomal translocation in leukemias particularly t(9;22) in CML patients has suggested that the positioning and chromatin topology of CTs might play a role in the occurrence of particular chromosomal rearrangements associated with malignant transformation. Using 3D‐FISH and 3D‐SIM we have determined the positions, distances and volumes of CT9 and CT22 and in BCR‐ABL1 genes, in interphase nuclei of CD34+ bone marrow (BM) cells from CML RxDx and in CR patients compared to healthy donors’ CD34+ MBM and PBMC. Likewise, we mapped relevant histone modifications finding a particular difference in TC22 and H3K27me3 histone mark from CML CR CD34+ cells.image

Mechanically scanned interference pattern structured illumination imaging.

We present a fully lensless single pixel imaging technique using mechanically scanned interference patterns. The method uses only simple, flat optics; no lenses, curved mirrors, or acousto-optics are used in pattern formation or detection. The resolution is limited by the numerical aperture of the angular access to the object, with a fundamental limit of a quarter wavelength and no fundamental limit on working distance. While it is slower than some similar techniques, the lack of a lens objective and simplification of the required optics could make it more applicable in difficult wavelength regimes such as UV or X-ray.

Noise-robust coded-illumination imaging with low computational complexity.

Coded-illumination (CI) imaging is a feasible technique enabling resolution enhancement and high-dimensional information extraction in optical systems. It incorporates optical encoding and computational reconstruction together to help overcome physical limitations. Existing CI reconstruction methods suffer from a trade-off between noise robustness and low computational complexity, which are both requisite for practical applications. In this paper, we propose a novel noise-robust and low-complexity reconstruction scheme for CI imaging. The scheme runs in an iterative way, and each iteration consists of two phases. First, the measurements are input into a novel non-uniform and adaptive weighted solver, whose weight updates in each iteration. This enables effective identification and attenuation of various measurement noise from coarse to fine. Second, the preserved latent information enters an alternating projection optimization procedure, which reconstructs target image by imposing support constraints without matrix lifting. We have successfully applied the scheme to structured illumination imaging and Fourier ptychography. Both simulations and experiments demonstrate that the method obtains strong robustness, low computational complexity, and fast convergence. The scheme can be adopted for various incoherent and coherent CI imaging modalities with wide extensions.