Research On The Wood Internal Defects Detection Method Based On The Radar Wave

There are often cavity, decayed, or worms damaged phenomenons inside the trees growing in natural environment as well as the historic buildings with wooden beams or pillars. Thus, the nondestructive detection method is of vital importance in maintenance of trees and ancient buildings. However, the existing testing methods normally need nailing needles on the tree or wooden beams of historic buildings, which will damage the objectives themselves; some other methods either of low measurement accuracy or insecurity. In order to solve the above problems, this paper employs a method based on radar detection of internal defects of wood.First of all, this paper analyzes the characteristics of electromagnetic wave propagation in the interior of the timber. We learned that dielectric constant are mainly affected by internal moisture content of wood. The main work is as follows:1. An experiment to measure the relationship equation between the dielectric constant and moisture content of four wood species is designed. The experimental results obtained four wood relationship equation.2. The measured relationship equation is applied to the actual defect detection of timber. The results showed that the precision of relationship equation has been improved to some extent.3. Since the device measured grayscale images are black and white, Amateurs are hard to see the location of the defect. Therefore, this paper end-use three-dimensional reconstruction method, first the tomographic image are achieved by format conversion, filtering and edge detection. At last, three-dimensional reconstruction of trees internal defects was conducted in the matlab platform. Through three-dimensional reconstruction, trees internal defects can be measured in a more direct perception.