Ground-Buried Fiber-Optic Sensors for Object Identification

Abstract

Currently available perimeter-security systems use ground-buried fiber-optic sensors to detect objects on the ground surface, and some of them compare the observed signal patterns with those in a predefined library to identify specific types of objects. However, such qualitative approaches neglect a wealth of information contained in the measured signal. In this paper a more rational approach is presented that uses ground-buried distributed fiber-optic strain sensors with very high spatial and strain resolution to quantify the strain field induced by an object in contact with the ground surface. The contact interactions on the ground surface are calculated from the strain measurements using a mechanical soil model and inverse analysis algorithms similar to those used in image deblurring. The approach should enable a variety of applications where the knowledge of contact interactions on the ground surface is beneficial, from biodiversity survey, perimeter security, and weigh-in-motion systems to biomechanical applications and sports medicine.