Ultrasonic imaging of standing trees: factors influencing the decay detection

Abstract

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.

Ultrasound computed tomography on standing trees: accounting for wood anisotropy permits a more accurate detection of defects

“…The choice of an interpolation to 32 sensors was linked to a previous research showing that reconstruction algorithms such as SIRT (used in the proposed method) converged from 30 transducer positions (Arciniegas et al 2014b). The sinogram interpolation has shown to be an alternative to increase the defect identification capacity when using a limited number of sensors (Espinosa et al 2019c).…”

Integrating Thermal Indices and Phenotypic Traits for Assessing Tree Health: A Comprehensive Framework for Conservation and Monitoring of Urban, Agricultural, and Forest Ecosystems

“…When considering non-invasive techniques while simultaneously accounting for factors such as sensitivity, accuracy, cost, time requirements, and operational simplicity [50], infrared thermography (IRT) emerges as a prominent technique among the plethora of available options such as static bending and transverse vibration techniques [51], groundpenetrating radar methods [52], sonic/ultrasonic tomography [53], and electrical resistivity tomography [54]. In the field of ecology, IRT has found widespread application [55][56][57], demonstrating its effectiveness in diverse fields such as detecting pests in forested areas [58,59], monitoring crop vegetation [60,61], identifying water stress [62][63][64], and diagnosing fungal infestations [65,66].…”

Analysis of Imaging Internal Defects in Living Trees on Irregular Contours of Tree Trunks Using Ground-Penetrating Radar

“…To avoid damage to valuable trees, non-invasive methods are used to detect early defects, as they generally occur in the center of the wood and cannot be accurately monitored and measured from the outside [1]. At present, methods of nondestructive testing (NDT) are commonly used, such as electromagnetic wave detection [2], stress wave detection [3], infrared thermography [4], ultrasonic detection [5], microwave tomography [6,7], etc. Ground-penetrating radar (GPR), as an efficient, non-polluting, and safe NDT method, has great potential not only in the estimation of root parameters [8] but also in the health assessment of defects in the internal part of the tree trunk.…”