We evaluate the use of a smoothed space-frequency distribution (SSFD) to retrieve optical phase maps in digital speckle pattern interferometry (DSPI). The performance of this method is tested by use of computer-simulated DSPI fringes. Phase gradients are found along a pixel path from a single DSPI image, and the phase map is finally determined by integration. This technique does not need the application of a phase unwrapping algorithm or the introduction of carrier fringes in the interferometer. It is shown that a Wigner-Ville distribution with a smoothing Gaussian kernel gives more-accurate results than methods based on the continuous wavelet transform. We also discuss the influence of filtering on smoothing of the DSPI fringes and some additional limitations that emerge when this technique is applied. The performance of the SSFD method for processing experimental data is then illustrated.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1364/ao.42.007066 | DOI Listing |
Biomed Opt Express
December 2024
Britton Chance Center for Biomedical Photonics and MoE Key Laboratory for Biomedical Photonics, Advanced Biomedical Imaging Facility, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
Neurovascular coupling (NVC) is crucial for maintaining brain function and holds significant implications for diagnosing neurological disorders. However, the neuron type and spatial specificity in NVC remain poorly understood. In this study, we investigated the spatiotemporal characteristics of local cerebral blood flow (CBF) driven by excitatory (VGLUT2) and inhibitory (VGAT) neurons in the mouse sensorimotor cortex.
View Article and Find Full Text PDFClin Chim Acta
December 2024
Laboratory of Clinical Pathology, Azienda Sanitaria Universitaria Integrata, Udine, Italy.
External quality assurance (EQA) programs play a pivotal role in monitoring laboratory practices, allowing each laboratory to evaluate the consistency of results across different methods as well the ability of individual laboratories to compare and improve over time their own performance. The objective of our study was to analyze the UK NEQAS EQA reports for the "Antibodies to Nuclear and Related Antigens" program from 2013 to 2023, to assess the overall level of harmonization of the responses for anti-nuclear antibody (ANA) testing by indirect immunofluorescence (IIF), in terms of both pattern and titer consensus. As a second aim, we analyzed the impact of the introduction in UK NEQAS EQA reports of the International Consensus on ANA Patterns (ICAP) nomenclature and of digital image recognition on the harmonization of the ANA HEp-2 IIF test.
View Article and Find Full Text PDFJ Exp Biol
November 2024
School of Physics, Georgia Tech, 837 State Street NW, Atlanta, GA, 30332, USA.
A diversity of organisms live within underground environments. However, visualizing subterranean behavior is challenging because of the opacity of most substrates. We demonstrate that laser speckle imaging, a non-invasive technique resolving nanometer-scale movements, facilitates quantifying biological activity in a granular medium.
View Article and Find Full Text PDFSpeckle noise, mechano-physical noise, and environmental noise are inevitably introduced in digital holographic coherent imaging, which seriously affects the quality of phase maps, and the removal of non-Gaussian statistical noise represented by speckle noise has been a challenging problem. In the past few years, deep learning methods based on convolutional neural networks (CNNs) have made good progress in removing Gaussian noise. However, they tend to fail when these deep networks designed for Gaussian noise removal are used to remove speckle noise.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2024
International School of Photonics, Cochin University of Science and Technology, Kochi, Kerala, India; Digital University Kerala, India.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!