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Wavenumber domain r...
Wavenumber domain regularization for near-field acoustic holography by means of modified filter functions and cut-off and slope iteration
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Scholte, R. (author)
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- Lopez Arteaga, Ines (author)
- Eindhoven University of Technology
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Roozen, N. B. (author)
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Nijmeijer, H. (author)
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(creator_code:org_t)
- 2008
- 2008
- English.
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In: Acta Acoustica united with Acustica. - 1610-1928 .- 1861-9959. ; 94:3, s. 339-348
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.3...
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Abstract
Subject headings
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- Planar Near-field Acoustic Holography (PNAH) is an acoustic imaging method based on the inverse solution of the wave equation. Wavenumber domain low-pass filtering is an essential operation in the PNAH process. An increasingly higher wavenumber filter cut-off results in a "blow-up" of the inverse solution, which is a characteristic of an ill-posed problem. On the other hand, lower cut-off wavenumbers result in spatial acoustic data at very low resolution, where highly detailed information is discarded. Thus, an optimal solution for the cut-off wavenumber somewhere in between is needed. This paper introduces two modified filter functions, namely a modified exponential and a modified Tikhonov filter, that are specifically designed for application in PNAH and compares them with a number of more general applied filter functions. Regularization methods are introduced that exploit the k-space to obtain near-optimal low-pass filter parameter selection at high computational efficiency. These filter functions are discussed and their parameters are selected by k-space application of L-curve, Generalised Cross-Validation and the newly introduced and well-applicable Cut-Off and Slope iteration. Simulations of various sources show that the optimal regularization method is highly dependent on the type of source, the spatial distribution and measurement noise. Finally, a robust regularization strategy is proposed which automatically produces high quality results for a wide range of practical conditions.
Subject headings
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)
Keyword
- Acoustic holography
- Acoustic imaging
- Acoustics
- Data recording
- Dynamic loads
- Holographic interferometry
- Holography
- Interferometry
- Laser recording
- Photoacoustic effect
- Photonics
- Signal filtering and prediction
- Wave equations
- Wave filters
- Acoustic data
- Blow-up
- Cross validations
- Cut-off
- Filter functions
- High-quality
- Ill-posed problems
- In-between
- Inverse solutions
- K-space
- L curves
- Low resolution
- Low-pass filtering
- Measurement noises
- Near-field Acoustic Holography
- Optimal regularization
- Optimal solutions
- Planar near-field
- Regularization methods
- Spatial distributions
- Wave number domains
- Wave numbers
- Imaging techniques
Publication and Content Type
- ref (subject category)
- art (subject category)
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