Ultrasonic Imaging of Reaction Wood in Standing Trees

International audienceThe quality of the Ultrasonic Computed Tomography (UCT) imaging device, in term of spatial resolution, sensitivity or dynamic, is a function of the wavelength, the number of transducers, the ultrasonic field generated and the inversion algorithm. This latter factor was studied using four inversion techniques for the tomography of trees. Two new methods, Partial Least Squares method - PLS, and Layer Stripping - LS, are compared to two classical methods, Filtered Backprojection - FBP, and Simultaneous Iterative Reconstruction Technique - SIRT. An original numerical phantom of tree was used and the effects of the variation of the number of transducers and the noise level were analyzed. The PLS was found to converge slowly but reached a high performance for the reconstruction of the projection values (slowness). PLS method was also characterized by a fast computation time. However, the PLS method gave a poor image quality (high sensitivity to noise level and presence of outlier values). The main advantage of the LS method was its high robustness to the noise level. The computing time was however the weakest point of LS method. A combination of the two classic FBP-SIRT methods seemed the most suitable except for the computation time. However, an improvement of the convergence conditions of PLS method (very fast computing time; including also curved rays), with the use of SIRT method, would constitute a promising solution

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“…Relatively fews tudies are conducted on these topics, especially on the last point that is of great importance to the community [38,39].…”

Section: Resultsmentioning

confidence: 99%

Travel-Time Ultrasonic Computed Tomography Applied to Quantitative 2-D Imaging of Standing Trees: A Comparative Numerical Modeling Study

Arciniegas¹,

Brancheriau²,

Gallet³

et al. 2014

Acta Acustica united with Acustica

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“…The receiver probe then converts the received pulse into an electrical signal that is appropriately amplified and visualized for travel time measurements. Here, a square wave (SW) train may also be used to send more energy at a specific frequency (Brancheriau et al 2011a(Brancheriau et al , 2012.…”

Section: Ultrasonic Techniquesmentioning

confidence: 99%

“…The temporal envelope was then used to determine travel time. The first arrival time was determined using either the first point above the background noise threshold (Brancheriau et al 2011a) or the maximum of the envelope t Max [equivalent to a conventional determination by cross-correlation between input and output signals; Brancheriau et al (2011bBrancheriau et al ( , 2012)] (Fig. 1).…”

Section: Travel Time Determinationmentioning

confidence: 99%

Literature review of acoustic and ultrasonic tomography in standing trees

Arciniegas

Prieto

Brancheriau

et al. 2014

Trees

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Key message High-resolution imaging is possible if high-frequency sensors are used together with a signalprocessing and inversion algorithm that is well suited to a low signal-to-noise ratio and the effect of wood anisotropy. Wood is a biological growth medium, and given that standing trees adapt themselves in their growth to environmental conditions, their material properties vary with age. These changes result in variations that are far more complex than anisotropy. Wood quality and intraspecific variability can thus be studied to gain an understanding of the development mechanisms of trees, and this can be useful for clonal selection and the management of tree communities. A number of techniques are available to determine wood properties in standing trees, but the signal-processing approaches currently used are not always robust and do not always provide the image resolution needed in the particular cases of acoustic or ultrasonic tomography. This review paper thus aims to present important aspects that should be taken into account when using tomography techniques and addresses a number of open problems. A brief review of current non-destructive wood imaging techniques is initially presented followed by a comparison of the protocols, methods and models used in acoustic and ultrasonic tomography. The devices cited were studied in terms of measurement systems and signal processing. The analysis aimed to highlight and analyze the advantages and disadvantages of each device and describe challenges and trends. The effect of various parameters is discussed: frequency, signal-to-noise ratio, number of sensors and inversion algorithm. General conclusions are then drawn in relation to future signal-processing work in the acoustic and ultrasonic tomography of standing trees. (Résumé d'auteur

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“…Nadaljnji razvoj te metodologije, z možnostmi poenostavitve meritev, je mogoč z uporabo atenuacije in dušenja mehanskih vibracij, zvočnih ali ultrazvočnih, za zaznavanje notranjih anomalij v stoječih drevesih. Pretekle raziskave so potrdile uporabo atenuacije ultrazvoka za zaznavanje reakcijskega lesa (Brancheriau et al 2012b, Saadat-Nia et al 2011 ter napreduječih bakterijskih okužb v drevesih (Leininger et al 2001).…”

Section: Uvodunclassified

Forest science for future forests: forest genetic monitoring and biodiversity in changing environments: LIFEGENMON final conference: from 21st of September till 25th of September 2020, Ljubljana, Slovenia: book of abstracts

Kraigher¹,

Železnik²

2020

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Ultrasonic Imaging of Reaction Wood in Standing Trees

Cited by 9 publications

References 4 publications

Travel-Time Ultrasonic Computed Tomography Applied to Quantitative 2-D Imaging of Standing Trees: A Comparative Numerical Modeling Study

Travel-Time Ultrasonic Computed Tomography Applied to Quantitative 2-D Imaging of Standing Trees: A Comparative Numerical Modeling Study

Literature review of acoustic and ultrasonic tomography in standing trees

Forest science for future forests: forest genetic monitoring and biodiversity in changing environments: LIFEGENMON final conference: from 21st of September till 25th of September 2020, Ljubljana, Slovenia: book of abstracts

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