New York:Using the power of the light around us, researchers have significantly improved an innovative light-sensing system that tracks a person's behaviour continuously and unobtrusively in real time. The new StarLight system has a wide range of practical applications, including virtual reality without on-body controllers and non-invasive real-time health monitoring. The new system dramatically reduces the number of intrusive sensors, overcoming furniture blockage and supporting user mobility. “We're turning light into a ubiquitous sensing medium that tracks what we do and senses how we behave," said senior study author Xia Zhou, assistant professor of computer science at Dartmouth College. “Our work addresses several key practical issues of light-based sensing, including the furniture blockage, reliance on a large number of light sensors and user mobility. It pushes the vision of light sensing closer to practice,” he informed. The researchers studied the use of purely ubiquitous light around us to track users' behaviour, without any cameras, on-body devices or electromagnetic interference. They were able to reconstruct a user 3D skeleton by leveraging the light emitted from LED panels on the ceiling and only 20 light sensors on the floor. The system can track the user's skeleton as he or she moves around in a room with furniture and other objects. “Imagine a future where light knows and responds to what we do. We can naturally interact with surrounding smart objects, such as drones and smart appliances and play games, using purely the light around us,” Zhou noted. It can also enable a new, passive health and behavioural monitoring paradigm to foster healthy lifestyles or identify early symptoms of certain diseases, the authors noted. The results are scheduled to be presented at the “ACM MobiSys 2016” conference on mobile systems, applications and services in Singapore.