Estimating The Density of Wood Specimens using Synthetic Aperture Radar Imaging

The density of wood is one of the most important physical properties when it comes to understanding its mechanical behavior. The strength of a wood specimen is directly related to the amount of wood material in a given volume, making the accurate determination of density essential for the analysis of wood structures. The use of non-destructive evaluation (NDE) techniques (e.g., microwave/radar, ultrasonic, stress wave, and X-ray) is a powerful approach for condition assessment of existing wood structures. Synthetic aperture radar (SAR) imaging, with its remote and subsurface sensing abilities, provides information about the mechanical properties of wood structures without obstructing their functionality. The objective of this paper is to use SAR imaging to determine the differences in density in a variety of different wood species. Five 14 in.-by-2 in.-by-0.75 in. wood specimens were manufactured. Each wood specimen was imaged vertically inside an anechoic chamber using a 10 GHz SAR system. It was found that SAR amplitude distribution was affected by the density of wood specimens. It was also found that the increase of wood density leads to the increase of contour area of SAR images.