An Accurate Geometrical Multi-Target Device-Free Localization Method Using Light Sensors

Device-free localization (DFL) is a technique that can locate targets wearing no devices, and has become an attractive technique for wide applications, such as intrusion detection and gesture recognition. In recent years, research on indoor localization using light sensor mainly focuses on traditional active localization methods, which require photodiodes being attached to targets. In this paper, we explore the visible light-based DFL method. In DFL, shadowed areas caused by different targets may overlap when multiple targets simultaneously exist in a small monitored area, which increases difficulties both in counting target and achieving accuracy localization. This paper presents an accurate geometrical multi-target device-free localization method, which includes a sector ring model and an adaptive multi-target positioning (AMTP) algorithm. The proposed model does well in describing the relationship between the target location and the shadowed area, which provides essential observation information for DFL. The proposed AMTP algorithm improves the accuracy of counting and locating multiple targets through updating weight map of the monitored area in each iteration. Numerous simulation results show that the proposed DFL method effectively achieves multi-target location, and outperforms the traditional geometrical localization method and the fingerprinting localization method both in counting and localization accuracy.