In addition to the visual information contained in intensity and color, imaging polarimetry allows visual information to be extracted from the polarization of light. However, a major challenge of imaging polarimetry is image degradation due to noise. This paper investigates the mitigation of noise through denoising algorithms and compares existing denoising algorithms with a new method, based on BM3D (Block Matching 3D). This algorithm, Polarization-BM3D (PBM3D), gives visual quality superior to the state of the art across all images and noise standard deviations tested. We show that denoising polarization images using PBM3D allows the degree of polarization to be more accurately calculated by comparing it with spectral polarimetry measurements.
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http://dx.doi.org/10.1364/JOSAA.35.000690 | DOI Listing |
This study investigates the role of pitch size in achieving high numerical aperture (NA) and focusing efficiency in metalens design, while demonstrating how high refractive index materials contribute to performance enhancement by enabling smaller pitch sizes through reduced filling ratios. Silicon-rich nitride (SRN) was chosen as the material platform due to its high refractive index, CMOS compatibility, and cost-effective fabrication. Two SRN-based metalenses were designed: a geometric phase metalens (GPM) and a propagation phase metalens (PPM), each evaluated at aspect ratios of 10:1 and 4:1.
View Article and Find Full Text PDFSensors (Basel)
December 2024
IDEKO Research Center, Basque Research and Technology Alliance (BRTA), 20870 Elgoibar, Spain.
Traditional marker-based photogrammetry systems often require the attachment and removal of a sticker for each measured point, involving labor-intensive manual steps. This paper presents an innovative approach that utilizes raised, cross-shaped markers, referred to as 'molded markers', directly embedded into composite pieces. In this study, these markers, commonly employed in other industrial processes, serve as fiducial markers for accurate photogrammetry.
View Article and Find Full Text PDFJ Med Imaging (Bellingham)
January 2025
University of Arizona, College of Biomedical Engineering, Tucson, Arizona, United States.
Purpose: Diffusion magnetic resonance imaging (dMRI) quantitatively estimates brain microstructure, diffusion tractography being one clinically utilized framework. To advance such dMRI approaches, direct quantitative comparisons between microscale anisotropy and orientation are imperative. Complete backscattering Mueller matrix polarized light imaging (PLI) enables the imaging of thin and thick tissue specimens to acquire numerous optical metrics not possible through conventional transmission PLI methods.
View Article and Find Full Text PDFArXiv
December 2024
Department of Imaging Physics, Delft University of Technology, 2628 CJ Delft, The Netherlands.
Three-Dimensional Polarized Light Imaging (3D-PLI) and Computational Scattered Light Imaging (ComSLI) map dense nerve fibers in brain sections with micrometer resolution using visible light. 3D-PLI reconstructs single fiber orientations, while ComSLI captures multiple directions per pixel, offering deep insights into brain tissue structure. Here, we introduce the Scattering Polarimeter, a high-speed correlative microscope to leverage the strengths of both methods.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
Recent advancements in novel fiber-coupled and portable terahertz (THz) spectroscopic imaging technology have accelerated applications in nondestructive testing (NDT). Although the polarization information of THz waves can play a critical role in material characterization, there are few demonstrations of polarization-resolved THz imaging as an NDT modality due to the deficiency of such polarimetric imaging devices. In this paper, we have inspected industrial carbon fiber composites using a portable and handheld imaging scanner in which the THz polarizations of two orthogonal channels are simultaneously captured by two photoconductive antennas.
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