CAREER: Ubiquitous Sensing Using Computational Light

Dartmouth College, Hanover NH

Investigators

Abstract

The ability to sense and detect human movement is critical to the development of data-driven mobile health systems. It can help detect disease and foster behavioral changes to cultivate healthy lifestyles. Existing sensing technologies either require users to constantly wear or carry on-body potentially cumbersome devices, are vulnerable to electromagnetic interference, or present severe privacy risks involving leaking of sensitive data and images. This project takes a entirely different approach to addressing these issues. It exploits the use of ubiquitous light as a low-cost, unobtrusive, and accurate sensing medium capable of simultaneously sensing people and their surrounding context. The proposed vision " LightSense " consists of off-the-shelf LED lights on the ceiling and a few low-cost photodiode sensors sprinkled in the environment. The photodiodes passively capture light blockage created by the human body and reconstruct fine-grained user behaviors in real time. LightSense leverages light to turn a space into a cognitive space, which recognizes our presence, senses our behaviors such as postures and high-level activities while monitoring our health status indicators such as levels of stress. LightSense is empowered by Visible Light Communication (VLC) that turns the visible light into computational light. It contains the following novel systems and algorithmic designs: 1) a novel VLC network architecture with LED panels and sparse photodiodes to ease system deployment; 2) algorithmic and systems designs to separate light rays from dense LEDs, optimize the placement of photodiodes, and overcome the blockage of other objects (e.g., furniture, other users); 3) a new VLC primitive that allows light communication and sensing to be sustained even under extremely low light conditions; and 4) learning algorithms to infer physical activities, derive movement characteristics, and monitor psychological state. LightSense will be evaluated using real-scale testbeds and user studies. Results from this project will establish the foundational pieces to define a new research space (visible light sensing), and will generate far-reaching impact on promoting innovative interaction designs and enabling new types of precise health monitoring.