Investigation of self-adaptive algebraic tomography for gas reconstruction in larger temperature range by multiple wavelengths absorption spectroscopy

Li, Ning; Lv, Xiaojing; Wang, Chunsheng

doi:10.3788/col201412.121103

Cited by 4 publications

(4 citation statements)

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“…The iteration number is employed to characterize the convergence speed, while the NAAD is used to evaluate the reconstruction quality [ 46 ]. As shown in Figure 7 , for a ω parameter of 0.05, the computation reaches 31,865 iterations.…”

Section: Resultsmentioning

confidence: 99%

“…The computational workload remains moderate under this choice, while ensuring a commendable reconstruction quality. The iteration number is employed to characterize the convergence speed, while th NAAD is used to evaluate the reconstruction quality [46]. As shown in Figure 7, for a ω parameter of 0.05, the computation reaches 31,865 iterations.…”

Section: Reconstruction Results Evaluation Under Different Optical Pa...unclassified

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Vertical Distribution Mapping for Methane Fugitive Emissions Using Laser Path-Integral Sensing in Non-Cooperative Open Paths

Wang,

Li,

et al. 2024

Sensors

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Observing the vertical diffusion distribution of methane fugitive emissions from oil/gas facilities is significant for predicting the pollutant’s spatiotemporal transport and quantifying the random emission sources. A method is proposed for methane’s vertical distribution mapping by combining the laser path-integral sensing in non-non-cooperative open paths and the computer-assisted tomography (CAT) techniques. It uses a vertical-plume-mapping optical path configuration and adapts the developed dynamic relaxation and simultaneous algebraic reconstruction technique (DR-SART) into methane-emission-distribution reconstruction. A self-made miniaturized TDLAS telemetry sensor provides a reliable path to integral concentration information in non-non-cooperative open paths, with Allan variance analysis yielding a 3.59 ppm·m sensitivity. We employed a six-indexes system for the reconstruction performance analysis of four potential optical path-projection configurations and conducted the corresponding validation experiment. The results have shown that that of multiple fan-beams combined with parallel-beam modes (MFPM) is better than the other optical path-projection configurations, and its reconstruction similarity coefficient (ε) is at least 22.4% higher. For the different methane gas bag-layout schemes, the reconstruction errors of maximum concentration (γm) are consistently around 0.05, with the positional errors of maximum concentration (δ) falling within the range of 0.01 to 0.025. Moreover, considering the trade-off between scanning duration and reconstruction accuracy, it is recommended to appropriately extend the sensor measurement time on a single optical path to mitigate the impact of mechanical vibrations induced by scanning motion.

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Section: Resultsmentioning

confidence: 99%

Section: Reconstruction Results Evaluation Under Different Optical Pa...unclassified

Vertical Distribution Mapping for Methane Fugitive Emissions Using Laser Path-Integral Sensing in Non-Cooperative Open Paths

Wang,

Li,

et al. 2024

Sensors

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“…On the other hand, a smaller value of θ can result in the reconstruction parameters falling into a local optimal solution, and hence, the reconstructed distribution tends to become steeper. Therefore, in the iteration process, θ needs to be adjusted according to the trend of the reconstruction parameters, and the amplitude of the smoothing coefficient θ can be automatically tuned according to the ratio of the reconstruction parameter to the mean value of other reconstruction parameters around it [29]. This ensures both the quality of the reconstructed target and the convergence of regularization.…”

Section: Principles Of the Miaro Algorithmmentioning

confidence: 99%

“…Therefore, the establishment of suitable and accurate regularization terms becomes key to the success of a regularization method. Li et al [16] developed a Modified Adaptive Algebraic Reconstruction Technique (MAART) to reconstruct the distributions of concentration and temperature simultaneously under incomplete projections for fast computation and high quality. In this method, the author introduced two correction coefficients, the relaxation factor and the smoothing factor, on the basis of the traditional algebraic reconstruction algorithm.…”

Section: Introductionmentioning

confidence: 99%

Reconstruction Algorithm Optimization Based on Multi-Iteration Adaptive Regularity for Laser Absorption Spectroscopy Tomography

Zhao,

Du,

Zhang

et al. 2023

Applied Sciences

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Laser absorption spectroscopy tomography is an effective combustion diagnostic method for obtaining simultaneous two-dimensional distribution measurements of temperature and gas molar concentrations. For the reconstruction process of complex combustion flames, a new algorithm named ‘multi-iterative adaptive optimization regularization’ (MIARO) is proposed. This algorithm is a further development of another algorithm known as the ‘modified adaptive algebraic reconstruction technique’ (MAART) with the improvement of the initial value and adaptive regularization parameter selections. In MIARO, the problem of the MAART’s initial value sensitivity is compensated for, and in addition, reconstruction parameters are also introduced into the regularization so that both the quality of reconstruction and the convergence of regularization are guaranteed. In butane burner experiments, an average relative error of 1.82% was achieved with MIARO, compared to 2.44% with MAART, which is a significant reduction of 25.1%. The simulation and experimental results clearly demonstrate that the MIARO algorithm can be used to reconstruct dynamic combustion fields and eliminate boundary artifacts with improved measurement accuracy and robustness.

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Reconstruction of Smoke Plume Concentration Peaks Based on Modified MAX-DOAS Tomography

Wei

Tong

2015

Chinese Journal of Chemical Physics

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Optical tomography system based on modified simultaneous iterative reconstruction technique is designed to real-time monitor spatial distribution and diffusion process of smoke plume in a power plant. Concentration profiles, rather than just a point value, of smoke plume concentrations are the goal of this method, and the tomography algorithm is analyzed. According to incomplete projection data in the process of reconstruction and exiting noise interference, the modified simultaneous iterative reconstruction technique (SIRT) is adopted to extract the information of the trace gas concentration by a fan beam scanning and is compared to the conventional SIRT. Three evaluation indexes show that the reconstruction effect is the best by choosing proper relaxation factor, which reduces the index d to 0.044 from 0.435 and reduces the index r to 0.044 from 0.376 for 5500 iterations. Hence, the modified algorithm performs better in estimating the shape of the plume, this method is used to process the measured spectra in field campaign, the reconstruction results and the measured data are basically consistent, which is further confirmed by the experimental results.

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Investigation of self-adaptive algebraic tomography for gas reconstruction in larger temperature range by multiple wavelengths absorption spectroscopy

Cited by 4 publications

References 0 publications

Vertical Distribution Mapping for Methane Fugitive Emissions Using Laser Path-Integral Sensing in Non-Cooperative Open Paths

Vertical Distribution Mapping for Methane Fugitive Emissions Using Laser Path-Integral Sensing in Non-Cooperative Open Paths

Reconstruction Algorithm Optimization Based on Multi-Iteration Adaptive Regularity for Laser Absorption Spectroscopy Tomography

Reconstruction of Smoke Plume Concentration Peaks Based on Modified MAX-DOAS Tomography

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