Virtual road signs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Computer Systems Engineering at Massey University, Palmerston North, New Zealand
Conventional road signs are subject to a number of problems and limitations. They are unable to disseminate dynamic information to road users, their visibility is heavily dependent on environmental conditions, they are expensive to maintain and frequently the target of vandals and thieves. Virtual road signs (VRS) differ from conventional signs in that they exist only in an information database - no physical signs exist on the roadside. By projecting virtual signs into a driver's field of view at the correct time, virtual road signs attempt to mimic conventional road signs. In addition, their visibility is independent of weather and traffic conditions, they can be tailored to specific driver and vehicle needs (such as truck drivers), and they cannot be vandalised like physical signs. This thesis examines many of the major technical design decisions that must be made in implementing a virtual road sign system. A software prototype was designed and written to implement an experimental VRS system. The prototype served as a testbed to assess the technical feasibility of a VRS system and investigate alternative VRS designs. One limitation of the project was the lack of suitable display device that could display virtual signs inside a vehicle in real-time. Therefore, this project examined only the proof-of-concept. A test world was created around a university campus in which virtual signs were "erected" to target a visitor to the campus. The prototype used a handheld GPS receiver to track a vehicle as it was driven around the campus. A Kalman filter was implemented to filter the GPS data and predict the motion of the vehicle when GPS data was unavailable. A laptop PC provided onboard processing capability inside the test vehicle. The prototype shows that technical implementation of virtual road signs is potentially feasible, subject to limitations in current display devices such as heads-up displays. Potential applications include signs custom designed for tourists to indicate places of interest, bilingual signage, and aiding co-drivers in rally car driving. Before large-scale implementation can be considered, however, much research is needed, particularly with respect to systems acceptability to the public and road authorities.