On-Road Dynamic Pattern Projection Using an Active Mirror for Vehicle Warning Systems

Recently, the demand for vehicle warning systems to avoid collisions between vehicles and pedestrians has been increasingly growing. For the implementation of such systems, three types of vehicle-to-pedestrian (V2P) technologies are widely adopted. In the first, vehicles communicate with pedestrians via smart devices using dedicated short-range communications (DSRC), but it is neither simply intuitive nor fast responsive. In the second, vehicles generate a noise in order to help pedestrians avoid collisions, at the expense of disturbing others with unwelcome noise. In the last, an on-road short-range projection technique visually informs pedestrians that a vehicle is approaching, which can be more intuitive and responsive. However, the two main drawbacks of conventional on-road projections are that they involve a static pattern and narrow emission angle. This paper proposes an on-road dynamic pattern projection technique for grabbing more attention from pedestrians with various dynamic patterns and covering a wide emission angle using an active mirror. Theoretical analysis shows that the on-road projection pattern and its angle can easily be controlled by adjusting the switching frequency, duty-cycle, and amount of current flow in the control circuitry. The simulation and experimental results validate that various patterns can be projected within a projection angle of ±70° at a power consumption less than 0.98W.