Development of a multi-spectral thermal imager for measurement of the laser-induced damage temperature field

Wang, Zhentao; Dai, Jingmin; Yang, Sen; Hu, Tingdong

doi:10.1016/j.infrared.2022.104158

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…From the above experimental results, it can be seen that the method proposed in this paper avoids the process of assuming the relationship between spectral emissivity and other physical quantities; it also simplifies the multispectral thermometry model and exhibits the advantages of high inversion accuracy and fast calculation speed. In addition to the above features, and in comparison with previously reported methods [9,11], the method newly described here does not require limiting the emissivity range; this may be seen as an advantage, as it greatly improves the possibility of exploring the radiative properties of unknown materials or new composites. Moreover, the methods described in [9,11] both require large amounts of data to simulate the emissivity range; in this respect, the method used in the present study may be seen as more convenient.…”

Section: Advantages Of the Methods Proposed In This Papermentioning

confidence: 92%

“…In addition to the above features, and in comparison with previously reported methods [9,11], the method newly described here does not require limiting the emissivity range; this may be seen as an advantage, as it greatly improves the possibility of exploring the radiative properties of unknown materials or new composites. Moreover, the methods described in [9,11] both require large amounts of data to simulate the emissivity range; in this respect, the method used in the present study may be seen as more convenient. Finally, the method described in this paper offers an obvious advantage in terms of calculation speed compared with the method described in [11].…”

Section: Advantages Of the Methods Proposed In This Papermentioning

confidence: 92%

“…They used a five-channel, four-wavelength filter photometer, in which the fifth channel was used as a calibration channel, so that the infrared thermal imager could accurately collect data under multispectral channels. The spectral data collected by the instrument were inverted to determine the corresponding temperature field using the multispectral thermometry method, and the results showed that the measurement error of the multispectral thermal imager was <1.5% [9]. Ketui Daniel et al implemented a multispectral method using a curve-fitting technique through simulation to measure the surface temperatures of ceramic coatings in the presence of high ambient radiation and low emissivity.…”

Section: Introductionmentioning

confidence: 99%

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Multispectral Thermometry Method Based on Optimisation Ideas

Zhang,

Liu,

Wang

et al. 2024

Sensors

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Multispectral thermometry is based on the law of blackbody radiation and is widely used in engineering practice today. Temperature values can be inferred from radiation intensity and multiple sets of wavelengths. Multispectral thermometry eliminates the requirements for single-spectral and spectral similarity, which are associated with two-colour thermometry. In the process of multispectral temperature inversion, the solution of spectral emissivity and multispectral data processing can be seen as the keys to accurate thermometry. At present, spectral emissivity is most commonly estimated using assumption models. When an assumption model closely matches an actual situation, the inversion of the temperature and the accuracy of spectral emissivity are both very high; however, when the two are not closely matched, the inversion result is very different from the actual situation. Assumption models of spectral emissivity exhibit drawbacks when used for thermometry of a complex material, or any material whose properties dynamically change during a combustion process. To address the above problems, in the present study, we developed a multispectral thermometry method based on optimisation ideas. This method involves analysing connections between measured temperatures of each channel in a multispectral temperature inversion process; it also makes use of correlations between multispectral signals at different temperatures. In short, we established a multivariate temperature difference correlation function based on the principles of multispectral radiometric thermometry, using information correlations between data for each channel in a temperature inversion process. We then established a high-precision thermometry model by optimising the correlation function and correcting any measurement errors. This method simplifies the modelling process so that it becomes an optimisation problem of the temperature difference function. This also removes the need to assume the relationships between spectral emissivity and other physical quantities, simplifying the process of multispectral thermometry. Finally, this involves correction of the spectral data so that any impact of measurement error on the thermometry is reduced. In order to verify the feasibility and reliability of the method, a simple eight-channel multispectral thermometry device was used for experimental validation, in which the temperature emitted from a blackbody furnace was identified as the standard value. In addition, spectral data from the 468–603 nm band were calibrated within a temperature range of 1923.15–2273.15 K, resulting in multispectral thermometry based on optimisation principles with an error rate of around 0.3% and a temperature calculation time of less than 3 s. The achieved level of inversion accuracy was better than that obtained using either a secondary measurement method (SMM) or a neural network method, and the calculation speed achieved was considerably faster than that obtained using the SMM method.

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Section: Advantages Of the Methods Proposed In This Papermentioning

confidence: 92%

Section: Advantages Of the Methods Proposed In This Papermentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Multispectral Thermometry Method Based on Optimisation Ideas

Zhang,

Liu,

Wang

et al. 2024

Sensors

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“…Under high energy laser, optical elements are prone to appear laser-induced damage (LID) and form defects on the surface of optical elements. In addition, the damage will aggravate under subsequent laser irradiation, which will eventually cause irreversible functional damage [1][2][3]. Thermal effect is the main origin of the damage when the continuous wave (CW) laser interaction occupies for a long time [4,5], which is usually related to the impurities content, porosity, uniformity and other factors of the optical elements, and affected by the processing quality, surface impurities, surface scratches and other factors as well.…”

Section: Introductionmentioning

confidence: 99%

Thermal ablation behavior of infrared optical element under high energy CW laser

Xiang,

You,

Miao

et al. 2024

International Academic Conference on Optics and Photonics (IACOP 2023)

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Thermal ablation is quite a complex process in high energy continuous wave (CW) laser facility, and it is crucial to understand the damage mechanism for stable operation of laser system. In this paper, we observe the behavior of contaminants-induced damage via a self-build optics testing platform. The waveband of optical coatings (Ta2O5 and SiO2) under test is dedicated for the infrared. Based on 100kW level infrared CW laser, the thermal ablation process of the optical coatings and the substrate caused by typical surface contaminants (iron micro-particle) is recorded, which shows distinct results in many aspects. This work can be helpful for understanding the influence of contaminants and prevent the optical elements from thermal damage in high energy laser system.

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True temperature inversion for a multi-spectral pyrometer based on the inner penalty function constrained optimization algorithm

Zhu¹,

Xing²

2022

Infrared Physics & Technology

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Development of a multi-spectral thermal imager for measurement of the laser-induced damage temperature field

Cited by 8 publications

References 19 publications

Multispectral Thermometry Method Based on Optimisation Ideas

Multispectral Thermometry Method Based on Optimisation Ideas

Thermal ablation behavior of infrared optical element under high energy CW laser

True temperature inversion for a multi-spectral pyrometer based on the inner penalty function constrained optimization algorithm

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