Nondestructive evaluation of wooden logs using ground penetrating radar

Abstract This paper addresses the crucial need for a non-invasive method for precisely detecting the subsurface defects in wooden logs. The method utilises ground penetrating radar (GPR) technology which has the potential to be implemented in real time in saw mills in the near future. Internal defects such as knots, decays and embedded metals are of great concern for lumber production. Nondestructive scanning of logs using GPR to detect defects in logs prior to sawing can greatly increase the productivity and yield of high value defect-free lumber by optimal orientation of the saw blade, and prevent damage to saw blade from embedded metals. Also, GPR offers high speed scanning capability which is needed for future online implementation in saw mills. In this research, the scanned GPR data have been analysed to investigate the capability of GPR to detect subsurface defects such as metals, decays and knots. This paper presents the comprehensive results from GPR scanning of several wooden logs and shows comparisons with actual condition inside the log observed after sawing the log. The advantages of the GPR technique, experimental setup and data processing used for detection of subsurface defects in logs are explained in detail. This study has shown that GPR can be used to accurately identify the subsurface defects such as knots, decays and metallic nails inside the logs which are not visible from outside observations. The results show that GPR can be a very promising technique for future online implementation in saw mills. Keywords: ground penetrating radarradarnondestructive testingscanningsawmillingwoodtimberlogsdefectsknotsdecaysmetals Acknowledgements The authors would like to gratefully acknowledge the funding for this research provided by the U.S. Department of Agriculture under Grant/Contract No. 2004-34158-14390. The authors would also like to thank the Appalachian Hardwood Center at West Virginia University for providing the laboratory assistance in sawing the logs used in this research. Notes 1. sachin5578@gmail.com 2. Bhaskaran.Gopalakrishnan@mail.wvu.edu Additional informationNotes on contributorsSachin Agrawal 1. 1. sachin5578@gmail.com Bhaskaran Gopalakrishnan 2. 2. Bhaskaran.Gopalakrishnan@mail.wvu.edu