Relative entropy regularized TDLAS tomography for robust temperature imaging

Yong Bao, Rui Zhang, Godwin Enemali, Zhang Cao, Bin Zhou, Hugh McCann, Chang Liu

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Tunable diode laser absorption spectroscopy (TDLAS) tomography has been widely used for in situ combustion diagnostics, yielding images of both species concentration and temperature. The temperature image is generally obtained from the reconstructed absorbance distributions for two spectral transitions, i.e., two-line thermometry. However, the inherently ill-posed nature of tomographic data inversion leads to noise in each of the reconstructed absorbance distributions. These noise effects propagate into the absorbance ratio and generate artifacts in the retrieved temperature image. To address this problem, we have developed a novel algorithm, which we call Relative Entropy Tomographic RecOnstruction (RETRO), for TDLAS tomography. A relative entropy regularization is introduced for high-fidelity temperature image retrieval from jointly reconstructed two-line absorbance distributions. We have carried out numerical simulations and proof-of-concept experiments to validate the proposed algorithm. Compared with the well-established simultaneous algebraic reconstruction technique (SART), the RETRO algorithm significantly improves the quality of the tomographic temperature images, exhibiting excellent robustness against TDLAS tomographic measurement noise. RETRO offers great potential for industrial field applications of TDLAS tomography, where it is common for measurements to be performed in very harsh environments.
Original languageEnglish
JournalIEEE Transactions on Instrumentation and Measurement
Volume70
DOIs
Publication statusPublished - 13 Nov 2020

Keywords

  • image reconstruction
  • temperature measurement
  • entropy
  • temperature distribution
  • measurement by laser beam
  • inverse problems
  • regularization
  • two-line thermometry
  • laser absorption spectroscopy
  • tomography
  • relative entropy
  • temperature imaging

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering

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