Camera and LIDAR sensor in a single unit for advanced driver assistant systems

October 22, 2012 // By Christoph Hammerschmidt
Tiredness, distractions or loss of concentration are among the main causes of traffic accidents. Consequently, advanced driver assistance systems which help drivers in such situations can reduce the number of accidents. In order to provide reliable sensors which enable such driver assistance systems, automotive tier one Continental has developed a combination of an infrared laser (LIDAR) and a CMOS camera.

The unit is suited for installation directly behind the windscreen, typically in the mounting of the rear-view mirror. The sensor module is able to categorize objects in front of the vehicle and detect an imminent collision. In addition to the two sensors, the module houses the entire analysis unit.

In the speed range of up 72 km/h, the SRL-CAM400 can help drivers avoid a collision by initiating automatic emergency braking. The difference in speed between the vehicle and an object can be up to 40 km/h. If the speed differences are greater, emergency braking will at least considerably reduce the force of the impact. The new sensor module is currently at the pilot production stage, with series production planned to start in 2015.

CMOS cameras are already used for categorizing objects in front of a vehicle. However, by itself, a CMOS camera cannot always provide sufficiently reliable information for initiating automatic emergency braking. For this reason, This Continental combines this passive sensor technology with an infrared LIDAR in the SRL-CAM400. The LIDAR sensor transmits three pulsed infrared beams with a 905nm wavelength and measures the time-of-flight until the reflected beams reach the receiving optics. The sensor monitors a distance of more than ten meters in front of the vehicle, which classifies it as a short-range LIDAR system. From the speed of light and the time-of-flight, the sensor computes the distance to the object to an accuracy to 10 centimeters. In conjunction with the CMOS camera, the analysis unit in the sensor module now has access to both a robust means of object categorization and accurate distance measurement. Before automatic emergency braking is initiated, the two signal paths are compared with each other, thus further enhancing the probability that a correct decision will be made.

With tight cost restrictions in mind, particularly with regards to compact vehicles, the module has been designed as a scalable unit. Depending on the application, the