Use of high resolution digital images and NDT imaging techniques for the characterization of timber structural elements

The combined use of high resolution images of wood texture and non destructive imaging of internal defects of wood is proposed for the characterization of structural timber on site. Experimental results are presented, based on the integrated use of digital photogrammetry, ultrasonic tomography and image analysis techniques. The implemented methodology aims at investigating the exploitation of some digital imaging techniques as complementary tools to be used during visual inspection. The experimental activity was carried out, at the Laboratory of Materials and Structural Testing at the University of Trento. High resolution images of the material texture were acquired by means of a CCD camera, in order to produce detailed maps of wood strength affecting characteristics on the element surface. The acquired data were coupled with acoustic tomograms in both longitudinal-radial plane and cross-section plane. Features in both tomographic and photographic images, that reflect information about the macroscopic heterogeneities in the material, were extracted by image processing. Geometrical properties of the detected features were automatically determined from the processed images.