Intelligent carpet system, based on photonic guided-path tomography, for gait and balance monitoring in home environments

We report on the photonic variant of the previously introduced guided-path tomography (GPT), by demonstrating a system for footstep imaging using plastic optical fiber (POF) sensors. The 1 m x 2 m sensor head is manufactured by attaching 80 POF sensors on a standard commercial carpet underlay. The sensing principle relies on the sensitivity of POF to bending, quantified by measuring light transmission. The photonic GPT system, comprising the sensor head with processing hardware and software, covered by a mass-production general-purpose carpet top, successfully performs footstep imaging and correctly displays the position and footfall of a person walking on the carpet in real time. We also present the implementation of fast footprint center of mass calculations, suitable for recording gait and footfall. A split-screen movie, showing the frame-by-frame camera-captured action next to the reproduced footprints, can be downloaded at http://ieeexplore.ieee.org.