Continental is taking its automotive safety systems' capability into a new dimension—or as the company describes it, six dimensions. It plans to add a stereo camera to its ContiGuard forward looking braking system that is capable of "6-D" analysis.
“We must look for new ways of monitoring a vehicle’s surroundings,” said Dr. Andreas Brand, Head of Passive Safety at Continental’s Chassis and Safety Division. He explained that in addition to the spatial, 3-D position of any objects that it detects, the stereo camera provides crucial supplementary data that achieve a similar capability to the human eye via the parallax shift between two images.
“The stereo camera can determine the direction in which every pixel of an identified object is moving along the horizontal, vertical, and longitudinal axes'" he said. "This 6-D identification makes absolutely clear whether an object is moving and in which direction.”
Although the driver would always be in overall control, Brand stated that combined with object classification based on common characteristics, the process gives the camera a sufficiently high standard of decision-making certainty that it can initiate emergency braking of up to 1 g if the driver fails to react to the developing situation or to early warnings from the system.
The stereo camera’s capability would be particularly germane to situations involving pedestrians or with vehicles at intersections. Instead of prioritizing obstacles, safety systems should be able to provide support in every hazardous situation, believes Brand. He explained that in effect, a stereo camera system had two “eyes” and so was able to detect both size and distance of an object or objects. And unlike a mono camera system, it did not have to “learn” what it was viewing.
Continental’s stereo camera system comprises two, high-resolution CMOS (complementary metal-oxide semiconductor) cameras. Housed some 20 cm (7.9 in) apart, they are placed behind the windshield. Working together, they can measure, via analyzing electronics, object distance and height, computing perspective effects between left and right optical paths to achieve a parallax shift between two images.
For automotive safety applications, accuracy is essential. At 20 to 30 m (66 to 98 ft), the Continental system can achieve an accuracy of between 20 and 30 cm (7.9 and 11.8 in). It can do this even if its “picture” is suffering from image clutter, there is partial obscuration of its vision, or there is a lack of contrast between object and background.
Brand said the salient benefit of a stereo camera system was the capability to compare the two optical paths because the redundant information obtained when both images contained identical zones with matching characteristics enhanced the reliability of data and that the two paths supported each other in low-visibility conditions. It could provide the data for collision warning or for automatic braking to be applied earlier in the unfolding of an event.
Wilfried Mehr, Continental’s Head of Business Development for Advanced Driver Assistance Systems, believes that the stereo camera’s capability will mature to detect and differentiate between children, cyclists, and wheelchair users: “We are realizing a comprehensive obstacle-recognition system the like of which has never before been possible.”