Recent Progress in the Development of a Chemical Species Tomographic Imaging System to Measure Carbon Dioxide Emissions from Large-Scale Commercial Aero-Engines

Lengden, Michael; Stewart, George; Johnstone, Walter; Upadhyay, Abhishek; Wilson, David; Polydorides, Nick; McCann, H.; Liu, Chang; Enemali, Godwin; Tsekenis, Alex; Wright, Paul; Kliment, Josh; Archilla, Victor; Velasco, Javier; Sánchez-Valdepeñas, Jesús; Beltrán, Marta; Polo, V.; Armstrong, Ian; Mauchline, Iain

doi:10.1364/ais.2020.jm2f.3

Cited by 2 publications

(1 citation statement)

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“…This requirement is particularly important in BOS and LAS due to the nonlinear relationship between the QoI and measured signal(s). One solution is to perform instantaneous or time-resolved tomography using simultaneous measurements from multiple cameras or laser beams to reconstruct the QoI in an interrogation plane or volume, as has been done in BOS (Ihrke et al 2007, Atcheson et al 2008, Nicolas et al 2017, Amjad et al 2020, chemiluminescence imaging (Floyd and Kempf 2011, Worth and Dawson 2012, Mohri et al 2017, and LAS (Wright et al 2010, Lengden et al 2020, van der Kley et al 2021. This approach requires considerable optical access, which is not always possible and increases the cost and complexity of an experiment.…”

Section: Introductionmentioning

confidence: 99%

New transform to project axisymmetric deflection fields along arbitrary rays

Sipkens

Grauer

Steinberg

et al. 2021

Meas. Sci. Technol.

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Axisymmetric tomography is used to extract quantitative information from line-of-sight measurements of gas flow and combustion fields. For instance, background oriented schlieren (BOS) measurements are typically inverted by tomographic reconstruction to estimate the density field of a high-speed or high-temperature flow. Conventional reconstruction algorithms are based on the inverse Abel transform, which assumes that rays are parallel throughout the target object. However, camera rays are not parallel, and this discrepancy can result in significant errors in many practical imaging scenarios. We present a generalization of the Abel transform for use in tomographic reconstruction of light-ray deflections through an axisymmetric target. The new transform models the exact path of camera rays instead of assuming parallel paths, thereby improving the accuracy of estimates. We demonstrate our approach with a simulated BOS scenario in which we reconstruct noisy synthetic deflection data across a range of camera positions. Results are compared to state-of-the-art Abel-based algorithms. Reconstructions computed using the new transform are consistently more stable and accurate than conventional reconstructions.

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