Optical Speed Measurement and applications

Mobile robot navigation is a well researched discipline, looking back to a relatively long history however it is still a rich, active area for research and development. The ultimate goal for robots and intelligent vehicles seems to be autonomous navigation in complex real life scenarios. In order to achieve higher levels of autonomy sophisticated sensors and a sound understanding of the robot and its interaction with the environment is needed. The tasks involved can be divided to two basic categories; internal tasks involve keeping track of internal dynamic parameters, like speed accelerations, internal states etc. On the other hand the vehicle needs to be aware of external factors like obstacles, points of interest, possible routes from a to b and the respective costs. This is generally called robotic mapping. Intelligent Vehicle stands for a vehicle that senses the environment and provides information or control to assist the driver in optimal vehicle operation. Intelligent Vehicle systems operate at the tactical level of driving (throttle, brakes, steering) as contrasted with strategic decisions such as route choice, which might be supported by an on-board navigation system. (Bishop, 2005) Optical sensors supply by far the most information and as greater and greater processing capabilities become readily available their use becomes more widespread. Many researchers and companies have made more or less successful attempts at creating optical sensors for speed measurement, however to the knowledge of the authors no accurate high speed solution exist at the low price range. The aim of this article is to introduce a novel method for optical speed measurement and put it into perspective by summarizing other navigation methods and reviewing recent related work and possible applications. Also an introduction to optical flow calculation is given and practical considerations on texture analysis and sensor parameters are discussed backed up with simulation results.