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An airborne sensor measures the radiance spectrum, which is dependent on the spectral reflectance of the ground material, the orientation of the material surface, and the atmospheric and illumination conditions. We present an algorithm to estimate the surface spectral reflectance, given the sensor radiance spectrum corresponding to a single pixel. The algorithm uses a nonlinear physics-based image formation model. A low-dimensional linear subspace model is used for the reflectance spectra. The solar radiance, sky radiance, and path-scattered radiance are dependent on the environmental conditions and viewing geometry, and this interdependence is considered by using a coupled-subspace model for these spectra. The algorithm uses the Levenberg-Marquardt method to estimate the subspace model parameters. We have applied the algorithm to a large set of synthetic and real data.
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http://dx.doi.org/10.1364/josaa.24.000957 | DOI Listing |
Build Environ
March 2025
National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Morgantown, West Virginia, USA.
Influenza viruses can be aerosolized when slaughtering infected chickens, which increases the risk of zoonotic transmission. We conducted pilot experiments to measure the concentrations of airborne particles <2.5 μm during slaughtering and defeathering of chickens to help identify methods that can minimize workers' exposure to potentially hazardous aerosol particles.
View Article and Find Full Text PDFRev Sci Instrum
September 2025
State Key Laboratory of Deep Earth Exploration and Imaging, Jilin University, Changchun 130026, People's Republic of China.
In the semi-airborne frequency-domain electromagnetic (SAFEM) method, the total magnetic intensity (TMI) is derived from the vector synthesis of triaxial inductive magnetic sensors. However, non-orthogonal errors in the sensors introduce measurement inaccuracies. Traditional calibration techniques are unsuitable for induction magnetic sensors because they require either static magnetic field measurements or complex alternating current reference fields.
View Article and Find Full Text PDFTree Physiol
September 2025
Department of Plant Sciences, University of California, Davis, CA, USA.
Pigment dynamics in temperate evergreen forests remain poorly characterized, despite their year-round photosynthetic activity and importance for carbon cycling. Developing rapid, nondestructive methods to estimate pigment composition enables high-throughput assessment of plant acclimation states. In this study, we investigate the seasonality of eight chlorophyll and carotenoid pigments and hyperspectral reflectance data collected at both the needle (400-2400 nm) and canopy (420-850 nm) scales in Pinus palustris (longleaf pine) at the Ordway Swisher Biological Station in north-central Florida, USA.
View Article and Find Full Text PDFSensors (Basel)
August 2025
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Unmanned aerial vehicles (UAVs) are increasingly used in urban management and public services, but their potential misuse poses serious risks to public safety. Electrostatic sensors offer a promising approach for UAV detection and interception by capturing their electrostatic signatures during dynamic encounters. However, the sensor output is affected by the coupling between encounter parameters and circuit characteristics, making accurate modeling challenging.
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August 2025
Qingdao Innovation and Development Center, Harbin Engineering University, Qingdao 266500, China.
Magnetic interference compensation is critical for enhancing the accuracy of unmanned aerial vehicle (UAV) magnetic anomaly detection. To address the constrained compensation performance of the conventional Tolles-Lawson (T-L) model, which stems from insufficient parametric dimensionality, this study proposes a dynamic-enhanced extended compensation model. The novelly introduced attitude angle and attitude angular rate-coupled features expand the parameter set from 18 to 34 terms, significantly enhancing the characterization of the magnetic field.
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