Studies of narrow-band interference filters have shown that two mechanisms exist that cause drift to shorter wavelengths. One is dependent on the thermal history of the filter, and the other depends on the radiation history. The present paper presents experimental results on thermal effects; and it is shown that by a proper bake cycle, ZnS-cryolite filters are stable for years if stored at less than 38 degrees C.
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http://dx.doi.org/10.1364/AO.13.002675 | DOI Listing |
Lensless imaging offers a lightweight, compact alternative to traditional lens-based systems, ideal for exploration in space-constrained environments. However, the absence of a focusing lens and limited lighting in such environments often results in low-light conditions, where the measurements suffer from complex noise interference due to insufficient capture of photons. This study presents a robust reconstruction method for high-quality imaging in low-light scenarios, employing two complementary perspectives: model-driven and data-driven.
View Article and Find Full Text PDFRecent advances in near-field interference detection, inspired by the non-Hermitian coupling-induced directional sensing of Ormia ochracea, have demonstrated the potential of paired semiconductor nanowires for compact light field detection without optical filters. However, practical implementation faces significant challenges including limited active area, architectural scaling constraints, and incomplete characterization of angular and polarization information. Here, we demonstrate a filterless vector light field photodetector, leveraging the angle- and polarization-sensitive near-field interference of non-Hermitian semiconductor nanostructures.
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January 2025
College of Mechatronics Engineering, North University of China, Taiyuan 030051, China.
To enhance the positioning accuracy of autonomous underwater vehicles (AUVs), a new adaptive filtering algorithm (RHAUKF) is proposed. The most widely used filtering algorithm is the traditional Unscented Kalman Filter or the Adaptive Robust UKF (ARUKF). Excessive noise interference may cause a decrease in filtering accuracy and is highly likely to result in divergence by means of the traditional Unscented Kalman Filter, resulting in an increase in uncertainty factors during submersible mission execution.
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January 2025
Air and Missile Defense College, Air Force Engineering University, Xi'an 710051, China.
To address the issue of low-elevation target height measurement in the Multiple Input Multiple Output (MIMO) radar, this paper proposes a height measurement method for meter-wave MIMO radar based on transmitted signals and receive filter design, integrating beamforming technology and cognitive processing methods. According to the characteristics of beamforming technology forming nulls at interference locations, we assume that the direct wave and reflected wave act as interference signals and hypothesize a direction for a hypothetical target. Then, the data received are processed to obtain the height of low-elevation-angle targets using a cognitive approach that jointly optimizes the transmitted signal and receive filter.
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January 2025
College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China.
Aiming at the control challenges faced by unmanned surface vessels (USVs) in complex environments, such as nonlinearities, parameter uncertainties, and environmental perturbations, we propose a non-singular terminal integral sliding mode control strategy based on an extended state observer (ESO). The strategy first employs a third-order linear extended state observer to estimate the total disturbances of the USV system, encompassing both external disturbances and internal nonlinearities. Subsequently, a backstepping sliding mode controller based on the Lyapunov theory is designed to generate the steering torque control commands for the USV.
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