3D reconstruction of internal wood decay using photogrammetry and sonic tomography

Abstract

Knowledge of deteriorations within tree trunks is critical for arborists to conduct individual tree health assessments. Sonic tree tomography, a non‐destructive technique using sound waves, has been widely used to estimate the size and shape of internal decay based on sound wave velocity variations. However, it has commonly been applied to 2D horizontal or vertical cross sections and its accuracy is questionable due to the poor approximation of the shape of the cross section. This paper proposes an integration of close‐range photogrammetry and sonic tomography to enable accurate reconstruction of the exterior and interior of the tree trunk in 3D. The internal wood quality is represented by the spatially interpolated sound wave velocities, using the time of flight of the sound waves and the coordinates of the acoustic sensors obtained from the photogrammetric model. Experimental results show that the proposed approach provides a realistic 3D visualisation of the size, shape and location of the internal deteriorations.

3D Imaging of CRP and Ultrasonic Tomography to Detect Decay in a Living Adult Holm Oak (Quercus ilex L.) in Sardinia (Italy)

“…The 2D images were carefully selected and preprocessed with release 1.6 of Agisoft Metashape ® software (Agisoft LLC, St. Petersburg, Russia) based on Structure from Motion (SfM) methodology to avoid the use of noising data to finely align poses and generate a high dense points cloud textured with natural colors [6,22]. Three high density (each of about 10 million points) unstructured, unified, registered point clouds were restituted after image processing.…”

“…Proximal sensing methods can be essentially classified into three types: terrestrial laser scanner (TLS), with a high productivity of point clouds but very expensive because the instruments are costly and because the availability of specialized personnel to operate them is rather low; the magnetic motion tracker, which is as expensive as the TLS; and close range photogrammetry (CRP), considerably less expensive. Since the latter is one of the most precise surface data methods in use, it is becoming very popular for the 3D modelling of trees [3,4,6]. Moreover, among the techniques available for the modelling of the trees in forests or urban areas, internal body techniques are very effective in detecting physical parameters relating to the state of health of the inner parts of the trees or the quality of the wood.…”

“…For instance, CRP can provide 3D high resolution measurable models useful in the application of 3D ultrasonic tomography. The integration of geomatic and acoustic techniques is adopted in many fields of the applied sciences [6,[18][19][20][21][22].…”

Decay Detection in an Ancient Column with Combined Close-Range Photogrammetry (CRP) and Ultrasonic Tomography

“…Non-destructive techniques are constantly being improved in many fields of the applied sciences, as described by numerous authors [3][4][5][6][7][8][9][10][11][12][13]. For instance, contactless remote and proximal sensing methods can represent an optimal solution for the 3D accurate modelling of architectural elements.…”

Propagation velocity model and two-dimensional defect imaging of stress wave in larch (Larix gmelinii) wood

“…The stress wave technique has been widely used in nondestructive testing of wood because of its low cost, portability, and the fact that it is harmless to human beings (Wang et al 2008;Yue et al 2017;Zhang and Khoshelham 2020). Yang and Wang (2007) used the Arbotom to detect the internal decay of wood, and they compared and analyzed the actual estimated value with the estimated value of the internal decay area of wood.…”