Effect of sensor quantity on measurement accuracy of log inner defects by using stress wave

Wang, Lihai; Xu, Huadong; Zhou, Ci-lin; Li, Li; Yang, Xuechun

doi:10.1007/s11676-007-0045-5

Cited by 15 publications

(14 citation statements)

References 2 publications

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“…Sometimes the anthropogenic actions are so severe that they affect the integrity and even the stability of the trees, especially in the case of trees located in the cities, near the road, which are cut extremely intensively. In contrast to trees from forests managed for production, whose management is aimed at getting high quality wood for various industrial uses (Sandoz and Lorin 1996;Garrett 1997;Wang et al 2007;Mu et al 2010;Du et al 2015;Qu et al 2020;Lin and Wu 2013;Sandak et al 2020), for urban trees the main aim is to maintain their vitality, integrity, and stability for as long as possible (Kirkpatrick et al 2012;Camacho-Cervantes et al 2014;Sandoz and Lorin 1996;Deflorio et al 2008;Wang et al 2009). Initially, the condition of a tree and its maintenance or removal was decided by a single person, who visually evaluated it (van Wassenaer and Richardson 2009).…”

Section: Introductionmentioning

confidence: 99%

The agreement in accuracy between tomograms, resistograms, and the actual condition of the wood from lime trees harvested from cities

Musat

2023

BioRes

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The internal quality of the wood is one of the main factors affecting the stability of trees, and it has always been of great interest to science and practice. For this reason, the present study aims to compare the results obtained by wood tomograms with those of resistance to drilling and the visual appearance after cutting a slice with a chain-saw, both to evaluate the presence and dimensions of the inside defects, and also to evaluate the irregularities of the wood structure. Round pieces of lime wood harvested from public areas were used for comparison by taking sound tomograms, followed by taking resistograms on two perpendicular directions at the same level. The results showed that internal wood defects are not always the ones that lead to reduced speeds of sound propagation through the wood. In addition, there were instances in which changes in the internal structure of the wood led to improperly colored tomograms, namely the sections characterizing the point of insertion of a thick branch in the trunk, where the tomograms indicated low speeds of sound transfer through the wood in the stem and high speeds in the wood of the branch.

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Section: Introductionmentioning

confidence: 99%

The agreement in accuracy between tomograms, resistograms, and the actual condition of the wood from lime trees harvested from cities

Musat

2023

BioRes

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“…The application and propagation rules of SWT were studied by detecting defects in trees and assessing the safety conditions of trees (Wang et al, 2007). The number of sensors can influence the fit and error rate of stress wave images, at least 12 sensors are needed to make the image fit close to 90%, and the error rate is reduced to 0.1 (Wang, Xu & Zhou, 2007). Study has indicated that the relationship between stress waves and resistance values was significant (Allison & Wang, 2015).…”

Section: Introductionmentioning

confidence: 99%

Electric resistance tomography and stress wave tomography for decay detection in trees—a comparison study

Xiaoquan

Wang

Wacker

et al. 2019

PeerJ

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Background To ensure the safety of trees, two NDT (nondestructive testing) techniques, electric resistance tomography and stress wave tomography, were employed to quantitatively detect and characterize the internal decay of standing trees. Comparisons between those two techniques were done to make full use of the individual capability for decay detection. Methods Eighty trees (40 Manchurian ash and 40 Populus simonii) were detected, then wood increment cores were obtained from each cross disc trial. The Dt, which was defined as the value determined by the mass loss ratio of each wood core, was regarded as the true severity of decay. Using ordinary least-squares regression to analyze the relationship between Dt and De (De was defined as the severity of decay determined by electric resistance tomography) and between Dt and Ds (Ds was defined as the severity of decay determined by stress wave tomography). Results The results showed that both methods could estimate the severity of decay in trees. In terms of different stages of decay, when Dt < 30%, De had a strong positive correlation with Dt (R2 = 0.677, P < 0.01), while, when Dt ≥ 30%, Ds had a significant positive correlation relationship with Dt (R2 = 0.645, P < 0.01). Conclusion Electric resistance tomography was better than stress wave tomography for testing in the early stages of decay, while stress wave tomography can be used effectively in the late stage of decay. It is suggested that each technique can be used in the practice of internal decay testing of standing trees based on decay stages and operating conditions.

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“…Several factors influence the quality of the acoustic and ultrasonic images [10]. The number of sensors, for example, is directly related to the spatial resolution of the image; a larger number of sensors allows a smaller defective area detection [11,12]. The excitation signal used for testing is directly related to the precision of the TOF estimation, affecting the image reconstruction method [13,14].…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic imaging of standing trees: factors influencing the decay detection

Espinosa

Prieto

Brancheriau

et al. 2019

2019 XXII Symposium on Image, Signal Processing and Artificial Vision (STSIVA)

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Ultrasound Computed Tomography is a widely used technique for nondestructive control of materials. One application is the evaluation of the inner state of standing trees in urban areas. The quality of the tomographic image depends on several factors, such as the number of probes used and the image reconstruction algorithm. Here we are interested in evaluating the influence of using a reconstruction algorithm adapted to wood anisotropy, compared to the classic methods using an isotropic model, and the effect of numerically increasing the number of sensors and the time-of-flight measurements using an interpolation method, known as sinogram interpolation. A numerical configuration was tested, simulating the presence of an eccentric defect in a wood section. Reconstructed images were compared before and after the interpolation process, and a thresholding was applied to quantify the decay area estimation. A more detailed defect identification was obtained with the reconstruction algorithm adapted to wood anisotropy and the interpolation of the sensors.

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Effect of sensor quantity on measurement accuracy of log inner defects by using stress wave

Cited by 15 publications

References 2 publications

The agreement in accuracy between tomograms, resistograms, and the actual condition of the wood from lime trees harvested from cities

The agreement in accuracy between tomograms, resistograms, and the actual condition of the wood from lime trees harvested from cities

Electric resistance tomography and stress wave tomography for decay detection in trees—a comparison study

Ultrasonic imaging of standing trees: factors influencing the decay detection

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