- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Detection of bodies in maritime rescue operations using unmanned aerial vehicles with multispectral cameras
摘要： In this study, we use unmanned aerial vehicles equipped with multispectral cameras to search for bodies in maritime rescue operations. A series of flights were performed in open‐water scenarios in the northwest of Spain, using a certified aquatic rescue dummy in dangerous areas and real people when the weather conditions allowed it. The multispectral images were aligned and used to train a convolutional neural network for body detection. An exhaustive evaluation was performed to assess the best combination of spectral channels for this task. Three approaches based on a MobileNet topology were evaluated, using (a) the full image, (b) a sliding window, and (c) a precise localization method. The first method classifies an input image as containing a body or not, the second uses a sliding window to yield a class for each subimage, and the third uses transposed convolutions returning a binary output in which the body pixels are marked. In all cases, the MobileNet architecture was modified by adding custom layers and preprocessing the input to align the multispectral camera channels. Evaluation shows that the proposed methods yield reliable results, obtaining the best classification performance when combining green, red‐edge, and near‐infrared channels. We conclude that the precise localization approach is the most suitable method, obtaining a similar accuracy as the sliding window but achieving a spatial localization close to 1 m. The presented system is about to be implemented for real maritime rescue operations carried out by Babcock Mission Critical Services Spain.
关键词： environmental monitoring,aerial robotics,learning,emergency response,perception
更新于2025-09-10 09:29:36
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THERMOLUMINESCENCE OF NEWLY DEVELOPED HIGHLY SENSITIVE α-Al2O3:C BY THE VERTICAL GRADIENT FREEZING METHOD
摘要： A highly sensitive α-Al2O3:C crystal was directly grown by the vertical gradient freezing (VGF) method using Al2O3 and graphite powder as the raw materials. The main thermoluminescence (TL) characteristics of α-Al2O3:C detectors grown by the VGF method and TLD-500K detectors were compared. The α-Al2O3:C grown by the VGF method shows good dosimetric properties, such as high TL sensitivity (152 times higher than that of the TLD-100 at heating rate of 1°C/s), an extremely low residual signal of 0.03%, a minimum measurable dose of 0.12 μGy and an excellent linear response within the dose range studied from 1 μGy to 10 Gy. The α-Al2O3:C detectors grown by the VGF method have a higher sensitivity and a better linear response compared to the TLD-500K detectors. Both kinds of α-Al2O3:C can be used in an unannealed form and to measure the very low dose in environmental monitoring and personnel dosimetry.
关键词： α-Al2O3:C,personnel dosimetry,dosimetric properties,vertical gradient freezing method,thermoluminescence,environmental monitoring
更新于2025-09-09 09:28:46
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Low-Cost Submersible Turbidity Sensors Using Low-Frequency Source Light Modulation
摘要： Submersible turbidimeter and fluorometer design generally involves tradeoffs between ambient light rejection, sensitivity, and cost. We introduce an optical backscatter transducer in which the light source is modulated with a low-frequency (tens of Hz) square wave, with a detection scheme that mitigates the effects of external interference from ambient light and from 50- and 60-Hz sources. With this design, high-pass filtering and subsequent amplification enable sensitive measurements using inexpensive circuitry. Additional accuracy-enhancing features include: a rail-splitting virtual ground, which eliminates the potential for clipping at low signal levels; a reference output, which provides correction for the intensity of the internal light source; and error-tracking provisions, which flag the output if circuit voltages reach saturation limits during measurement. We have designed, constructed, and evaluated submersible turbidimeters which incorporate this transducer. These sensors were inexpensive to fabricate (U.S. $70 of materials and 4 h of labor) and were proof tested to 7 atm of water pressure. They responded linearly and reproducibly to formazin turbidity standard, with negligible inherent offset. A calibrated sensor exhibited bias ≤0.11 NTU in suspensions ranging from 0 to 8 NTU. A similar sensor with reduced circuit gain exhibited a one-to-one response to increasing turbidity in suspensions ranging from 0 to 815 NTU.
关键词： water quality,underwater technology,nephelometer,turbidimeter,fluorometer,fluorescence,optical backscatter,Environmental monitoring,turbidity sensor
更新于2025-09-09 09:28:46
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Size Determination in Particle Streams Using a Multistatic Dual Frequency Millimeter Wave Radar
摘要： A multistatic dual frequency radar operating at 91.5 GHz and 150.3 GHz is designed and utilized to measure particle dimensions in a multidisperse particle stream. From the physical relations a size measurement routine is derived. In a numerical study we then investigate how a multistatic antenna configuration can improve the state-of-the-art method which usually is performed with a monostatic radar. Based on the simulation results, we present the layout of the radar sensor and experimental setup. Finally, measurement results are provided and discussed.
关键词： radar,remote measurement,particle size,Antenna,environmental monitoring,complex source beam (CSB),configuration,particle streams,multistatic
更新于2025-09-04 15:30:14
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Mini-UAV-Borne Hyperspectral Remote Sensing: From Observation and Processing to Applications
摘要： In recent years, with the rapid development of unmanned aerial vehicles (UAVs) and lightweight hyperspectral imaging (HSI) sensors, mini-UAV-borne hyperspectral remote sensing (HRS) systems have been developed and demonstrate great value and application potential. Compared to spaceborne and airborne HSI systems, mini-UAV-borne HSI systems come with relatively low manufacturing and running costs and have thus become a new research focus in the field of HRS. This article focuses on recent developments in UAV-borne HRS, including UAV platforms, miniaturized hyperspectral sensors, system integration, data observation, and preprocessing. In addition, successful application cases in the domains of agriculture, forestry, geology, and environmental monitoring are introduced, and we discuss current UAV-borne systems and their developing trends.
关键词： forestry,environmental monitoring,hyperspectral remote sensing,HSI,geology,agriculture,UAV
更新于2025-09-04 15:30:14
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Biosensors in Applications
摘要： These days, especially, the attention is increasing in high technology of sensors designed for various uses in biological matter, biomedicine, drug improvement, security, nutrition safety and ecological monitoring and measuring. The system of these sensors should typically be handy and economical, on condition that quick response with reliability, high sensitivity, and negligible false-reading counts are provided. Biosensors have a multi-disciplinary nature including: biology, chemistry, physics, instrumentation, electronics, optics, and market. The biosensors are detecting devices that combine a transducer with biologically sensitive and selective components. Biosensors can quantity combinations existing in the environment, chemical procedures, food and human body at inexpensive charge in comparison with traditional techniques. This editorial article briefly focuses on an overview of Biosensors, examples and providing a new vista of developments and applications.
关键词： biomedicine,environmental monitoring,Biosensors,food safety,applications
更新于2025-09-04 15:30:14
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Size determination in Particle Streams using a Multistatic Dual Frequency Millimeter Wave Radar
摘要： A multistatic dual frequency radar operating at 91.5 GHz and 150.3 GHz is designed and utilized to measure particle dimensions in a multidisperse particle stream. From the physical relations a size measurement routine is derived. In a numerical study we then investigate how a multistatic antenna configuration can improve the state-of-the-art method which usually is performed with a monostatic radar. Based on the simulation results, we present the layout of the radar sensor and experimental setup. Finally, measurement results are provided and discussed.
关键词： radar,remote measurement,particle size,environmental monitoring,complex source beam (CSB),particle streams,multistatic,antenna configuration
更新于2025-09-04 15:30:14