Subaru sees today’s premium-model radar- and laser-based forward vision systems as too expensive and too vulnerable to damage in otherwise minor collisions. That’s why the company has partnered with Hitachi to develop a stereoscopic vision system using computer analysis of images from a pair of conventional video cameras mounted behind the windshield.
“By mounting them behind the windshield, the cameras are out of range for damage from fender-benders,” explained Dave Sullivan, Subaru Car Line Manager. Additionally the pair of cameras give a 25-degree field-of-view, compared to 10-15 degrees for a radar or laser system.
“It can keep track of multiple vehicles in other lanes,” he explained. “It will keep an eye on vehicles in side lanes, looking at them as potential threats.”
Charge-coupled device (CCD) cameras are commonplace in consumer electronics and are much cheaper than radars or lasers, Sullivan said. Their use will result in one of the least expensive forward vision systems available in North America, according to the company.
EyeSight provides precollision braking control and collision mitigation, lane departure and sway warning, and adaptive cruise control functions. The precollision braking system can stop the car short of striking a stationary object at speeds below 19 mph (30 km/h) and can also avoid contact at higher speeds with objects that have a speed differential of less than 19 mph.
At higher speeds and speed differentials, the collision mitigation system automatically brakes to shed as much speed as possible before impact, reducing the force of the crash.
The cameras also watch the lane markers and line to warn drivers if they wander across a line when the turn signal is not used. On highways, the adaptive cruise control automatically follows the car ahead at a safe distance at speeds up to 87 mph (140 km/h). It can automatically brake the car to a stop in stop-and-go traffic, and the car can be released to go forward again using the cruise control’s resume button.
The system also has the ability to prevent crashes that might occur, for example, when a driver thinks the car is in reverse gear to back out of a parking space, but it is actually in drive. In this case, if there is a solid object in front of the car, the system will see it and will cut the throttle to prevent accidentally ramming a wall or another car, said Sullivan.