A hyperspectral reflectance confocal microscope (HSCM) was realized by CNR-ISC (Consiglio Nazionale delle Ricerche-Istituto dei Sistemi Complessi) a few years ago. The instrument and data have been already presented and discussed. The main activity of this HSCM has been within biology, and reflectance data have shown good matching between spectral signatures and the nature or evolution on many types of cells. Such a relationship has been demonstrated mainly with statistical tools like Principal Component Analysis (PCA), or similar concepts, which represent a very common approach for hyperspectral imaging. However, the point is that reflectance data contains much more useful information and, moreover, there is an obvious interest to go from reflectance, bound to the single experiment, to reflectivity, or other physical quantities, related to the sample alone. To accomplish this aim, we can follow well-established analyses and methods used in reflectance spectroscopy. Therefore, we show methods of calculations for index of refraction , extinction coefficient k and local thicknesses of frequency starting from phase images by fast Kramers-Kronig (KK) algorithms and the Abeles matrix formalism. Details, limitations and problems of the presented calculations as well as alternative procedures are given for an example of HSCM images of red blood cells (RBC).
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http://dx.doi.org/10.3390/molecules21121727 | DOI Listing |
Front Plant Sci
January 2025
College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China.
Chlorophyll density (ChD) can reflect the photosynthetic capacity of the winter wheat population, therefore achieving real-time non-destructive monitoring of ChD in winter wheat is of great significance for evaluating the growth status of winter wheat. Derivative preprocessing has a wide range of applications in the hyperspectral monitoring of winter wheat chlorophyll. In order to research the role of fractional-order derivative (FOD) in the hyperspectral monitoring model of ChD, this study based on an irrigation experiment of winter wheat to obtain ChD and canopy hyperspectral reflectance.
View Article and Find Full Text PDFJ R Soc Interface
January 2025
Faculty of Information Technology, University of Jyväskylä, Jyvaskyla, Finland.
The design of photobioreactors for microalgae cultivation aims to achieve an architecture that allows the most efficient photosynthetic growth. The availability of light at wavelengths that are important for photosynthesis is therefore particularly crucial for reactor design. While testing different reactor types in practice is expensive, simulations could effectively limit the range of material and reactor design options.
View Article and Find Full Text PDFIn this paper, we studied the sidewall conditions of 28 × 52 µm InGaN-based blue and green micro-LEDs with different sidewall angles and their effects on external quantum efficiency (EQE). Our findings indicate that steeper sidewall mesas can reduce non-radiative recombination and leakage current, which is beneficial for achieving high internal quantum efficiency (IQE). However, as the sidewall angle increases, the light output from the micro-LED tends to concentrate in the internal region, leading to a decrease in light extraction efficiency (LEE).
View Article and Find Full Text PDFPlant Cell Environ
January 2025
Remote Sensing Laboratory, Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi, India.
The generation of spectral libraries using hyperspectral data allows for the capture of detailed spectral signatures, uncovering subtle variations in plant physiology, biochemistry, and growth stages, marking a significant advancement over traditional land cover classification methods. These spectral libraries enable improved forest classification accuracy and more precise differentiation of plant species and plant functional types (PFTs), thereby establishing hyperspectral sensing as a critical tool for PFT classification. This study aims to advance the classification and monitoring of PFTs in Shoolpaneshwar wildlife sanctuary, Gujarat, India using Airborne Visible/Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) and machine learning techniques.
View Article and Find Full Text PDFSci Total Environ
January 2025
Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy. Electronic address:
Polyethylene nanoplastics (NPs) are widely diffused in terrestrial environments, including soil ecosystems, but the stress mechanisms in plants are not well understood. This study aimed to investigate the effects of two increasing concentrations of NPs (20 and 200 mg kg of soil) in lettuce. To this aim, high-throughput hyperspectral imaging was combined with metabolomics, covering both primary (using NMR) and secondary metabolism (using LC-HRMS), along with lipidomics profiling (using ion-mobility-LC-HRMS) and plant performance.
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