ADAS Safety Focus: Around View Systems
Automobile safety has driven several key innovations over the years from anti-lock brakes to airbags. German automakers have been first to leverage many of the most advanced technologies to improve driver safety and the overall driving experience. For example, German vehicles were the first to offer active lane keeping assist, which introduces a vibration to the steering wheel when the driver veers from his lane. Then came side assist radar to help drivers safely change lanes. It alerts the driver to a vehicle in their lanechanging blind spot with a light that comes on in the exterior side mirror. This was followed by stop-and-go and brake assist, which reduces the risk of rear-end collisions by quickly asserting the brakes before an impending crash.
These features have become more sophisticated over time and more pervasive, particularly with the introduction of safety cameras in the vehicle to eliminate the driver’s blind spot. Back-Up Camera Becomes Baseline The Insurance Institute of Highway Safety in the United States recently released a study that showed the chances of dying in a crash in a late-model vehicle have fallen by more than a third in the short span of three years. In fact, advances in safety have improved fatality rates by such a high margin, that automobiles being sold today offer meaningfully better safety statistics than even those introduced only five years ago. This is creating a virtuous cycle for automakers, giving drivers a reason to purchase a new vehicle sooner rather than later.
There are many reasons for the improved safety, from mechanical and structural improvements to increased safety-related legislation. But one of the most interesting and fastest growing safety applications is Advanced Driver Assistance Systems (ADAS). These systems use a combination of sensors, cameras and displays to provide greater driver visibility, and react to dangerous situations when a driver doesn’t. A blind spot is defined as the area where a driver’s view is obstructed. The back-up camera, mounted at the rear of the car with the display mounted in the rearview mirror or dashboard, has become a staple in mid-tohigh-end vehicles to provide driver visibility behind the vehicle and reduce accidents. The National Highway Traffic Safety Administration (NHTSA) estimates that rearview cameras can reduce back-over fatalities by over 50%. This feature became a mandated safety requirement in the U.S. when government regulation was passed requiring back-up cameras for all new vehicles beginning in 2018. Similar regulations are being considered in Europe and Asia, and automakers are already adopting rearview cameras across models. The TW9992 is a good example of an automotive video decoder IC addressing this global safety trend. It takes single-ended and differential composite video inputs from a car’s rearview camera and applies its Automatic Contrast Adjustment feature to dynamically reduce or boost image brightness and contrast for greater visibility and safety. The decoder then outputs the digitized video over its MIPI-CSI2 interface to the head unit’s SoC, which processes the video and sends it to the dashboard’s LCD screen or rearview mirror.