Application of inverse Abel techniques in in-line holographic microscopy

Apostolopoulos, M.I.; Taroudakis, Michael I.; Papazoglou, D. G.

doi:10.1016/j.optcom.2013.01.053

Cited by 11 publications

(14 citation statements)

References 19 publications

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“…3 seems to be applicable to a wide range of such flames. It is expected that the FLiPPID methodology described here can also be applied to other experimental techniques employing the Abel transform (e.g., modulated absorption/emission [43,44], laser extinction [42], or in-line holography [18,45]) simply by adjusting or extending Eq. 3.…”

Section: Resultsmentioning

confidence: 99%

“…1). In case of optically thin flames (i.e., negligible soot selfabsorption [9]) with axial symmetry, the recorded 2D projection P(x, z) and the 3D flame emission density R(r, z) are linked through the forward and reverse Abel transforms [18][19][20][21]:…”

Section: Introductionmentioning

confidence: 99%

“…Examples are integral transform techniques such as the Fourier-Hankel method [24] and its extension to filter noise [25], iterative methods [26], or fitting of polynomials or splines to the observed data [27][28][29]. Two techniques especially common in flame pyrometry are the basis-set expansion (BASEX) [18,19] and the onion-peeling method combined with a Tikhonov regularisation [20,21]. These two approaches are similar in that they regularise the reconstruction by supplying the measured data with additional information -a condition for a predefined level of spatial smoothness (set by smoothing and filtering parameters).…”

Section: Introductionmentioning

confidence: 99%

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Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

et al. 2019

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A new method is presented for performing the Abel inversion by fitting the line-of-sight projection of a predefined intensity distribution (FLiPPID) to the recorded 2D projections. The aim is to develop a methodology that is less prone to experimental noise when analysing the projection of antisymmetric objects, in this case co-flow diffusion flame images for colour ratio pyrometry. A regression model is chosen for the light emission intensity distribution of the flame cross-section as a function of the radial distance from the flame centre-line. The forward Abel transform of this model function is fitted to the projected light intensity recorded by a colour camera. For each of the three colour channels, the model function requires three fitting parameters to match the radial intensity profile at each height above the burner. This results in a very smooth Abel inversion with no artifacts such as oscillations or negative values of the light source intensity, as is commonly observed for alternative Abel inversion techniques, such as the basis-set expansion (BASEX) or onion-peeling. The advantages of the new FLiPPID method are illustrated by calculating the soot temperature and volume fraction profiles inside a co-flow diffusion flame, both being significantly smoother than those produced by the alternative inversion methods. The developed FLiPPID methodology can be applied to numerous other optical techniques for which smooth inverse Abel transforms are required.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

et al. 2019

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“…[52][53][54] After the completion of the testing summarized in Table I, a statistical method based upon a maximum entropy concept was published. 54 This technique (called MEVIR, for Maximum Entropy Velocity Image Reconstruction) limits noise and appears to produce robust images even with limited signal, making it an attractive candidate for further study.…”

Section: Image Reconstructionmentioning

confidence: 99%

Incorporating real time velocity map image reconstruction into closed-loop coherent control

Rallis

Burwitz

Andrews

et al. 2014

Review of Scientific Instruments

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We report techniques developed to utilize three-dimensional momentum information as feedback in adaptive femtosecond control of molecular dynamics. Velocity map imaging is used to obtain the three-dimensional momentum map of the dissociating ions following interaction with a shaped intense ultrafast laser pulse. In order to recover robust feedback information, however, the twodimensional momentum projection from the detector must be inverted to reconstruct the full threedimensional momentum of the photofragments. These methods are typically slow or require manual inputs and are therefore accomplished offline after the images have been obtained. Using an algorithm based upon an "onion-peeling" (also known as "back projection") method, we are able to invert 1040 × 1054 pixel images in under 1 s. This rapid inversion allows the full photofragment momentum to be used as feedback in a closed-loop adaptive control scheme, in which a genetic algorithm tailors an ultrafast laser pulse to optimize a specific outcome. Examples of three-dimensional velocity map image based control applied to strong-field dissociation of CO and O 2 are presented. © 2014 AIP Publishing LLC. [http://dx

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“…Smoothing the data, spline interpolation or polynomial fitting can be used to filter out noise and represent the discrete data as a continuous function. Furthermore, representing the data as Legendre polynomials or wavelets 21,22 , or using Fourier-Hankel transforms is also possible 23,24 .…”

Section: B Abel Transformationmentioning

confidence: 99%

Development of Validation Approaches for Numerical Simulation of Combustion Instability using Flame Imaging

Hardi¹,

Hallum²,

Huang³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Combustion dynamics are controlled by the coupling between heat addition and gas dynamic modes, hence their direct measurement and comparisons with prediction are key to improving computational tools as well as our fundamental understanding of the problem. Whereas gas dynamic modes are relatively easy to measure and compare, measurement and characterization of heat addition are much more difficult due to its complexity and the lack of any direct means of measurement. This paper demonstrates several methods for characterizing and comparing heat release from experiment and simulation. A model rocket combustor is used for the study. Comparisons are made for two configurations, one stable and one unstable. High-speed, line-of-sight imaging of OH* emission from the experiment was first phase averaged, and then treated with an Abel inversion routine to produce a dynamic, two-dimensional field of heat addition. The field before inversion could be compared to line-integrated calculations of heat release rate from three-dimensional large eddy simulations, and after inversion to azimuthally averaged cross-sections from simulations. Modal decomposition analysis of the two-dimensional fields were performed. The applicability and limitations of each comparison approach are assessed. Nomenclature J 0 = zero-order Bessel function of the first kind L op = length of oxidizer post, mm|inch p′ = dynamic pressure, MPa P cc = chamber pressure, MPa Φ = equivalence ratio ′ = unsteady term of a variable ω = frequency, Hz

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Application of inverse Abel techniques in in-line holographic microscopy

Abstract: Application of inverse Abel techniques in in-line holographic microscopy.

Cited by 11 publications

References 19 publications

Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

Improved methodology for performing the inverse Abel transform of flame images for color ratio pyrometry

Incorporating real time velocity map image reconstruction into closed-loop coherent control

Development of Validation Approaches for Numerical Simulation of Combustion Instability using Flame Imaging

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