Ver Intrinsico

It is important to maintain a suitable distance from the preceding vehicle on the freeway. However, it is very difficult for a driver to judge the real distance by eye alone. In addition, adaptive cruise control (ACC) 1-2 systems for controlling or measuring the headway distance from the host vehicle to the preceding vehicle are too expensive for most drivers. Thus the finding of a feasible low cost system for measuring the distance between vehicles on the freeway is the main goal of this paper.

Laser range finders can be divided technically into three categories or methods 3: time-of-flight, triangulation, and interferometer. A combination of the vision system and the triangulation method is widely used for different kinds of industrial applications 4-6. Many algorithms have been developed for different applications, and there exist various processors to speed up their execution. The range and resolution of these measurement systems are all dependent on the system layout. The range covered can be from some centimeters to some meters, and the resolution achieved can be less than 1μm. As a general rule, time-of-flight based systems are more appropriate for measuring long distances, while triangulation based systems are more suitable for measuring short distances and small ranges with high accuracy 7.

Most automotive laser radar systems are based on the time of flight method 1,2,8,9. A pulsed laser radar detection system (LIDAR) for obstacle detection in the automotive field is proposed 9. This consists of an infrared (IR) scanning system of the LIDAR type set up in a car. In addition, obstacle distance measurement can also performed by triangulation for up to 30 meters. A laser range finder with a measurement range from 5 to 40 meters was proposed by Bernard and Gaëlle10. It is based on optical power modulation, thus the name frequency modulation continue wave like (FMCW).

...