To a large extent, the performance of imaging systems is determined by their objectives, which affect properties as varied as collection efficiency, resolving power, and image distortions. Such limitations can be addressed by so-called aperture synthesis, a technique used, for instance, in radar, astronomy, and, increasingly, microscopy. Here, we apply such techniques to x-ray imaging and demonstrate how Fourier ptychography can be used at transmission x-ray microscopes to increase resolution, provide quantitative absorption and phase contrast, and allow for corrections of lens aberrations. We anticipate that such methods will find common and frequent applications, alleviating a number of limitations imposed by x-ray optical elements, offering an alternative approach to phase contrast imaging, and providing novel opportunities to mitigate radiation damage.
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http://dx.doi.org/10.1126/sciadv.aav0282 | DOI Listing |
Histochem Cell Biol
December 2024
School of Mechanical, Medical & Process Engineering, Queensland University of Technology, 60 Musk Ave/Cnr. Blamey St, Kelvin Grove, Brisbane, QLD, 4059, Australia.
Understanding the osteochondral junction, where non-mineralised cartilage and mineralised bone converge, is crucial for joint health. Current sample preparation techniques are insufficient for detailed spatial hyperspectral imaging analysis. Using the enhanced Kawamoto method, we used the super cryo embedding medium's temperature-dependent properties to transfer high-quality tissue samples onto slides for spatial imaging analysis.
View Article and Find Full Text PDFDeep neural network (DNN) models, particularly convolutional neural networks (CNNs), have demonstrated remarkable performance in biomedical image classification due to their ability to automatically learn features from large datasets. One common challenge in the preparation of large, microscopic datasets for DNN tasks is sample defocusing, potentially impairing the model performance. To handle defocusing, computational imaging, or specifically quantitative phase imaging (QPI), performs digital refocusing by using both the phase and the amplitude of the complex optical field.
View Article and Find Full Text PDFAdv Opt Mater
May 2024
Department of Biomedical Engineering, University of Connecticut, Storrs, USA.
Small Methods
October 2024
Optical Bioimaging Laboratory, Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore, 117576, Singapore.
Fourier ptychography (FP) is a high resolution wide-field imaging method based on the extended aperture in the Fourier space, which is synthesized from raw images with varying illumination angles. If FP is extended to coherent nonlinear optical imaging, the resolution could be further improved due to the increase of the cutoff frequency of the synthesized coherent optical transfer function (C-OTF) with respect to the order of nonlinear optical processes. However, there is a fundamental conflict between wide-field FP and nonlinear optical imaging, whereby the nonlinear optical imaging typically requires a focused excitation laser beam with high power density.
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