Thermal infrared (TIR) remote sensing is recognized as a powerful tool for collecting, analyzing and modeling of energy fluxes and temperature variations. Traditional aircraft, satellite or ground TIR platforms can provide valuable regional-scale environmental information. However, these platforms have limitations, such as expensive cost, complicated manipulation, etc. In comparison, small unmanned aircraft systems (UAS) have many advantages in TIR remote sensing applications over traditional platforms. In this paper, a low-cost UAV-based TIR remote sensing platform: AggieAir-TIR is introduced. AggieAir-TIR is a small, low-cost, flexible TIR remote sensing platform, which was accomplished at the Center for Self Organizing and Intelligent Systems (CSOIS) in Utah State University (USU). The detailed introduction of AggieAir-TIR remote sensing platform is provided in the paper. Furthermore, a low-cost TIR imaging camera calibration experiment is designed, and the calibration results are provided. Based on this AggieAir-TIR remote sensing platform, many remote TIR image data collection and analysis projects can be effectively implemented.

Low-cost UAV-based thermal infrared remote sensing: Platform, calibration and applications

In this article, we present a technical description of a new type of anemometer for gas and especially liquid flows with high temporal and spatial resolution. The principle of the measurement is based on the atomic force microscope technique where microstructured cantilevers are used to detect extreme small forces. We demonstrate the working principle and the design of the sensor, as well as calibration measurements and initial measurements of turbulent flows, which were performed in air and water flows.

Laser-cantilever anemometer: A new high-resolution sensor for air and liquid flows

UAV-borne thermal imaging involves the determination of ground surface temperature from thermal infrared measurements deploying an unmanned airborne vehicle (UAV). A large variety of UAVs is available and applied for different military and civil tasks. UAV-borne thermal imaging provides spatially distributed information of the ground surface temperature. In contrast to satellite or ground based measurement, the usage of a UAV allows us to obtain spatially distributed and geometrically highly resolved information on the ground surface temperature without the need to access the ground. The area can be flat or hilly, and steep walls and hillsides can be investigated easily. However, some problems, especially tasks related to mosaicking of the images, are not fully resolved to date. We address the detection of the anomalies in ground surface temperature induced by underground burning coal seams as example and describe the challenges and opportunities of UAV-borne thermal imaging, based on our experiences in this field.

Challenges and Opportunities for UAV-Borne Thermal Imaging

Presented here is an effective low-cost method for the temperature calibration of infrared cameras, for applications in the 0–100 °C range. The calibration of image gray level intensity to temperature is achieved by imaging an upwelling flow of water, the temperature of which is measured with a thermistor probe. The upwelling flow is created by a diffuser located below the water surface of a constant temperature water bath. The thermistor probe is kept immediately below the surface, and the distance from the diffuser outlet to the surface is adjusted so that the deformation of the water surface on account of the flow is small, yet the difference between the surface temperature seen by the camera and the bulk temperature measured by the thermistor is also small. The benefit of this method compared to typical calibration procedures is that, without sacrificing the quality of the calibration, relatively expensive commercial blackbodies are replaced by water as the radiative source (e≈0.98 for the wavelengths...

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A method for the temperature calibration of an infrared camera using water as a radiative source.

Temperature is an important process control, but is a difficult parameter to measure in the microwave processing of concrete. Owing to their metallic nature, conventional thermocouples are not suitable for temperature measurement in microwave fields. Some of the most popular sensors known to be immune to electromagnetic interference are based on optical fibres. This paper presents the results of an experimental study conducted to investigate the capability of fibre Bragg grating (FBG) sensors to monitor the surface temperatures of concrete specimens during microwave heating. A thermo-tracer camera was used to verify the accuracy of the FBG measurements. Moreover, the FBG measurements were compared with the results of numerical modelling and measurements taken using conventional thermocouples. The results show that the bare FBGs deployed in this study can be used to accurately measure concrete temperature in a microwave field.

Temperature sensing in microwave heating of concrete using fibre Bragg grating sensors

In conventional infrared (IR) thermographic cameras it is normally assumed that the ambient temperatures of optical objects are the same as the temperature determined at the camera head. In increasing cases of application of thermography, this assumption is not always satisfied, and often leads to erroneous results. In this article, we propose a determination scheme of the true temperature of such objects in an explicit form of equation to be solved by combining the readout temperature of the camera with a response function of the camera to a blackbody. The equation can be used to determine optical properties of components in an IR system. It also works to evaluate the contribution coming from each element along the optical path. Though the scheme is written in a form applicable to a specific camera among commercial products, it can be modified so that conventional IR cameras are conveniently used for thermographic determination of the temperature of gray objects in exotic environments.

Thermographic temperature determination of gray materials with an infrared camera in different environments

Axial and radial profiles of plasma potentials in the GAMMA10 tandem mirror are studied by use of an array of Langmuir probes. Application of fundamental ECRH in the plug region strong- ly varies the potential profiles. However, in the end region the axial potential profile normalized by the electron temperature remains nearly the same.

Axial and Radial Potential Distributions in the GAMMA10 Tandem Mirror

It is suggested experimentally that a plug potential forms in a different mechanism from the originally expected scenario in the present tandem mirror [T. Tamano, Phys. Plasmas 2, 2321 (1995)]. That is, the formation requires only electron cyclotron resonance heating experimentally. In this manuscript, therefore, the plug potential with continuous axial profile is analytically shown to be created with the plausible ion and electron distribution functions in a present tandem mirror, i.e., passing ions, mirror trapped ions in the thermal barrier, passing electrons, φ-trapped electrons in a plug potential, and the small amount of ions that are born around the plug region.

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Plug potential formation in a tandem mirror

The formation of plug potential is usually observed in a tandem mirror experiment without neutral beam injection in the plug region [Phys. Plasmas 2, 2321 (1995)]. The formation requires only the electron cyclotron resonance heating experimentally. In this Letter the plug potential is analytically shown to be created in a tandem mirror with passing ions, mirror trapped ions in the thermal barrier, passing electrons and φ‐trapped electrons in a plug potential but without high energy sloshing ions.

Generation of the saturated electrostatic potential along a magnetic field line

Cyclotron resonance heating of electrons in a magnetic beach is studied by rigorous numerical analysis of the electron trajectories. It is confirmed that a heating response function [Y. Kiwamoto et al., Phys. Plasmas 1 834 (1994)] connecting the velocity distributions in both sides of the resonance layer can be applied over a wider range of electron velocities than originally expected. For electrons mirror‐reflected close to the resonance layer, however, the electron velocity distribution after heating substantially deviates from the prediction of the response function. The deviation is quantitatively evaluated to obtain a criterion of applicability of the response function.

T. Tamano

Papers

Thermographic temperature determination of gray materials with an infrared camera in different environments

Axial and Radial Potential Distributions in the GAMMA10 Tandem Mirror

Plug potential formation in a tandem mirror

Generation of the saturated electrostatic potential along a magnetic field line

Electron cyclotron resonance heating near the turning point in inhomogeneous magnetic field