This paper extends and refines previous work on clustering of polarization-encoded images. The polarization-encoded images used in this work are considered as multidimensional parametric images where a clustering scheme based on Markovian Bayesian inference is applied. Hidden Markov Chains Model (HMCM) and Hidden Hierarchical Markovian Model (HHMM) show to handle effectively Mueller images and give very good results for biological tissues (vegetal leaves). Pretreatments attempting to reduce the image dimensionality based on the Principal Component Analysis (PCA) turns out to be useless for Mueller matrix images.
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http://dx.doi.org/10.1364/opex.12.001271 | DOI Listing |
Optical polarization is three-dimensional (3-D). Its complete information is described by the nine-component generalized Stokes vector (GSV). However, existing Stokes polarimetry and its design theory are primarily based on the paraxial four-component Stokes vector and 4 × 4 Mueller matrices.
View Article and Find Full Text PDFPurpose: Pre-clinical studies have demonstrated direct influences of the autonomic nervous system (ANS) on the immune system. However, it remains unknown if connections between the peripheral ANS and immune system exist in humans and contribute to the development of chronic inflammatory disease. This study had three aims: 1.
View Article and Find Full Text PDFJ Biophotonics
January 2025
School of Optoelectronics, Zhejiang University, Hangzhou, China.
The article describes a technique for digital holographic reconstruction of complex amplitude fields in diffuse blood facies using laser polarization-interference phase scanning to isolate a single scattered component of the object field. This method serves as the basis for developing algorithms for Mueller-matrix reconstruction of linear and circular birefringence parameters in the polycrystalline architectonics of blood facies. Statistical (central moments of the 1st-4th orders) and multifractal analyses (fractal dimension spectra) are applied to study the optical anisotropy maps of polycrystalline networks during blood dehydration.
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 PDFNanoscale
December 2024
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Carrer dels Til·lers, Bellaterra, 08193, Spain.
The nanoscale chiral arrangement in a bicomponent organic material system comprising donor and acceptor small molecules is shown to depend on the thickness of a film that is responsive to chiral light in an optoelectronic device. In this bulk heterojunction, a previously unreported chiral bis(diketopyrrolopyrrole) derivative was combined with an achiral non-fullerene acceptor. The optical activity of the chiral compound is dramatically different in the pure material and the composite, showing how the electron acceptor influences the donor's arrangement compared with the pure molecule.
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