In order to recover the holographic object information, a method based on the recording of two digital holograms, not only at different planes but also in a slightly off-axis scheme, is presented. By introducing a -phase shift in the reference wave, the zero-order diffracted term and the twin image are removed in the frequency domain during the processing of the recorded holograms. We show that the zero-order elimination by the phase-shifted holograms is better than working with weak-order beam and average intensity removal methods. For recording experimentally two -shifted holograms at different planes slightly off-axis, a single cube beam splitter is used. Computer simulations and experimental results, carried out to validate our proposal, show a high accuracy of /14 that can be comparable with phase-shifting digital holography. For high fringe spacing, our proposal could be applied in electron holography, avoiding high voltage in a biprism.
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http://dx.doi.org/10.1364/AO.57.002727 | DOI Listing |
Sci Rep
January 2025
Laboratory for Radiophysical and Optical Methods of Environmental Research, National Research Tomsk State University, Tomsk, Russia, 634050.
Monitoring the parameters and behavior of plankton makes it possible to assess the state of the aquatic ecosystem and detect the beginning of an environmental disaster at an early stage. In this respect, the most informative method for the in situ plankton study is underwater digital holography. This method allows obtaining information on the size, shape, and location of plankton individuals, as well as performing their classification and biotesting according to their behavioral responses using a submersible holographic camera non-invasively, in real time, and in the automatic mode.
View Article and Find Full Text PDFMicrosc Microanal
January 2025
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin 14195, Germany.
In catalysis research, the amount of microscopy data acquired when imaging dynamic processes is often too much for nonautomated quantitative analysis. Developing machine learned segmentation models is challenged by the requirement of high-quality annotated training data. We thus substitute expert-annotated data with a physics-based sequential synthetic data model.
View Article and Find Full Text PDFClin Radiol
December 2024
Department of Radiology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215006, China. Electronic address:
Aim: To assess transmural remission in patients with Crohn's disease using low-dose small bowel computed tomography (CT) perfusion scans.
Materials And Methods: Forty six patients were divided into active and remission phases based on Crohn's Disease Activity Index (CDAI) and C-reactive protein (CRP). Dual-source CT enterography with low-dose perfusion scans was conducted to generate perfusion parameter maps, including blood flow (BF), blood volume (BV), time to peak (TTP), mean transit time (MTT), and permeability of surface (PS).
J Hepatol
January 2025
MASLD Research Center, Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, CA, USA.
Background & Aims: A common genetic variant (rs738409) encoding isoleucine to methionine at position 148 in the PNPLA3 protein is a determinant of hepatic steatosis, inflammation, fibrosis, cirrhosis, and liver-related mortality. AZD2693 is a liver-targeted antisense oligonucleotide against PNPLA3 mRNA. We evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics in single ascending dose (SAD) and multiple ascending dose (MAD) studies.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Smart Computational Imaging Laboratory (SCILab), School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Lens-free on-chip microscopy (LFOCM) is a powerful computational imaging technology that combines high-throughput capabilities with cost efficiency. However, in LFOCM, the phase recovered by iterative phase retrieval techniques is generally wrapped into the range of -π to π, necessitating phase unwrapping to recover absolute phase distributions. Moreover, this unwrapping process is prone to errors, particularly in areas with large phase gradients or low spatial sampling, due to the absence of reliable initial guesses.
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