3D Visible Light Indoor Positioning by Bokeh Based Optical Intensity Measurement in Smartphone Camera

This paper proposes a three dimensional (3D) high-resolution indoor positioning system that uses a single light-emitting diode (LED) and a complementary metal-oxide semiconductor image sensor (CIS). The proposed visible light positioning system is based on the bokeh effect for improving the positioning accuracy. The 3D position is determined by received signal strength (RSS) and angle of arrival (AOA). Optical saturation in pixels causes severe performance degradation in the RSS-based positioning based on the CIS. The bokeh-based image reception technique resolves this problem by spreading the optical power to adjacent pixels. Additionally, via the bokeh effect, the size of the LED image on the CIS is maintained regardless of the distances. The accuracy of the LED extraction for the AOA can be improved by fixed LED size. These characteristics of the proposed positioning scheme are analyzed via simulations, and the feasibility of the method is verified based on the experimental results. The experimental results indicate an estimated positioning average error rate within 4%.