New Robust Obstacle Detection System Using Color Stereo Vision

Intelligent transportation systems (ITS) are divided into intelligent infrastructure systems and intelligent vehicle systems. Intelligent vehicle systems are typically classified in three categories, namely 1) Collision Avoidance Systems; 2) Driver Assistance Systems and 3) Collision Notification Systems. Obstacle detection is one of crucial tasks for Collision Avoidance Systems and Driver Assistance Systems. Obstacle detection systems use vehiclemounted sensors to detect obstuctions, such as other vehicles, bicyclists, pedestrians, road debris, or animals, in a vehicleâs path and alert the driver. Obstacle detection systems are proposed to help drivers see farther and therefore have more time to react to road hazards. These systems also help drivers to get a large visibility area when the visibility conditions is reduced such as night, fog, snow, rain, ... Obstacle detection systems process data acquired from one or several sensors: radar Kruse et al. (2004), lidar Gao & Coifman (2006), monocular vision Lombardi & Zavidovique (2004), stereo vision Franke (2000) Bensrhair et al. (2002) Cabani et al. (2006b) Kogler et al. (2006) Woodfill et al. (2007), vision fused with active sensors Gern et al. (2000) Steux et al. (2002) Mobus & Kolbe (2004)Zhu et al. (2006) Alessandretti et al. (2007)Cheng et al. (2007). It is clear now that most obstacle detection systems cannot work without vision. Typically, vision-based systems consist of cameras that provide gray level images. When visibility conditions are reduced (night, fog, twilight, tunnel, snow, rain), vision systems are almost blind. Obstacle detection systems are less robust and reliable. To deal with the problem of reduced visibility conditions, infrared or color cameras can be used. Thermal imaging cameras are initially used by militaries. Over the last few years, these systems became accessible to the commercial market, and can be found in select 2006 BMW cars. For example, vehicle headlight systems provide between 75 to 140 meters of moderate illumination; at 90 K meters per hour this means less than 4 seconds to react to hazards. When with PathFindIR PathFindIR (n.d.) (a commercial system), a driver can have more than 15 seconds. Other systems still in the research stage assist drivers to detect pedestrians Xu & Fujimura (2002) Broggi et al. (2004) Bertozzi et al. (2007). Color is appropriate to various visibility conditions and various environments. In Betke et al. (2000) and Betke & Nguyen (1998), Betke et al. have demonstrated that the tracking o