According to the latest statistics over 40% of all fatalities in the U.S. and 90% of all rollover crashes in Europe are related to unintended lane departures. There are many causes for unintended lane departure: the disruption of children in the back seat, talking on a cell phone, changing the radio, or falling asleep at the wheel.
To address this, Valeo a European maker of automotive switches and sensors, and Iteris, U.S. developer of intelligent transportation system technologies, have produced AutoVuean embedded camera-based lane-marking recognition and warning system. By monitoring the visual lane markings on the road and signaling the driver with an audible or tactile warning, AutoVue alerts a tired, distracted, or inattentive driver that he or she is about to leave their lane.
At the present time several factors influence the lateral control of a vehicle, including increased highway traffic, people spending more time driving, and the need for more safety and convenience in the vehicle. Knowing the lane width and vehicle position within it are important parameters for the driver to be aware of at all times. An extremely high market growth is predicted for such autonomous lane departure warning systems. At the same time, the automotive industry is making a step forward by implementing technology that could lead to developments in vehicle lateral control.
When AutoVue detects an unplanned lane departure, a sound is generated to alert the driver. The sound can be directional so that a left-hand departure will result in the sound being generated in a left vehicle speaker and a right hand departure in a right speaker. A camera views the road through a "wiped" section of the windshield, near the vehicle center line as shown below.
The image that follows shows the outline of the view processed in the crosshatched area seen in the previous diagram. The system camera is mounted on the windshield inside the cabin, near the center line of the vehicle. The imager is mounted high on the windshield for better functioning of the algorithm to track lane markings and to accommodate viewing over the hood.
Within the system is a central processor unit running a program that performs the lane-tracking and warning algorithm. The CPU runs this algorithm in conjunction with other embedded environment tasks (communications, initialization, and general task management). The lane-tracking algorithm accepts image input from the system camera and examines the lane markings. It determines whether or not a lane departure is imminent.
Upon such determination, and if all logic permits (for example, a turn signal is not active, and no system errors are present), a warning will be issued in association with the departure. If the system is also connected to a Controller Area Network (CAN) a message will be generated indicating which side of the vehicle the departure is occurring. This message can be used to create a warning to the driver through interfaces such as the infotainment system or steering system. Audible warnings are designed to be loud enough to overcome wind noise from an open window, as well as engine, traffic, and other noises, without being annoying.
The occurrence of internal system errors in self-checking will prevent issuance of any warning, as will failure to identify lane markings.
The AutoVue module hosts a complete lane tracking software solution including image capture and improvement, lane tracking algorithms, and drivers for the various system interfaces.