The Technology Behind Active Safety Systems in Cars

Want to know about the components used in active safety systems?

Today's cars are becoming smarter and safer with the help of advanced technology and data processing. New systems are arriving every year to assist drivers; from automatic high beam control to pre-collision braking systems, becoming the norm in practically all kinds of cars.

 

The Technology

There are three major forms of sensors used to assist drivers in cars: LIDAR, radar, and cameras. Each of these sensors can be beneficial in different ways and are often combined to achieve better solutions.

 

LIDAR

LIDAR (Light Detection And Ranging) is a technology that relies on lasers in order to measure distance. In automotive applications, these systems implement infrared (904nm) lasers that fire hundreds of pulses per second. LIDAR sensors are used by numerous companies such as Toyota's Dynamic Laser Cruise Control system, Volvo's Front Collision Mitigation Support system, and Infinity's Intelligent Cruise Control system. These LIDAR sensors are often paired with other technologies such as cameras or radar to provide additional data.
An example of this sensor fusion is Continental’s Multi-Function Camera with LIDAR (MFL) system that was developed for Toyota. This module's dual sensors are able to provide a pre-collision system, lane departure alert, and automatic high beam control.

Continental Corporation's Multi-Function Camera with LIDAR

 

Radar

Radar is one of the predominant sensor technologies used in advanced driver safety systems. These systems measure the time of flight, frequency shift, and the amplitude of the return signal to determine what information is relevant. Radar systems are used in automotive applications in systems from blind spot monitoring to forward collision warning. Just like the LIDAR sensors, radar sensors are often combined with other technologies such as cameras to obtain better data.
Delphi Automotive makes a module called the Radar and Camera System (RACam) that integrates both a radar sensor and camera into a single module. By using these two sensors, the RACam can provide a lot of functionality. According to Delphi, the dual sensor system can achieve full-speed adaptive cruise control, lane departure warning/lane keeping, headway alert, forward collision warning, pre-crash collision mitigation, full autonomous braking, pedestrian detection, object detection, headlight control, and traffic sign recognition. All of this technology is integrated into a package that's mounted inside the car in front of the rearview mirror.

 

Delphi's Integrated Radar and Camera System

 

Cameras

Cameras play a huge role in many driver assistance systems. Many systems use cameras and computer vision algorithms to augment other systems, as mentioned above, and to stand on their own. By using FPGA’s and powerful processors, sophisticated image processing can be done in real time to obtain valuable data. Some current vehicles are packed full of cameras that can provide many different forms of data. The diagram below shows what types of data can be obtained from cameras mounted in various locations.

XILINX's Driver Assistance System

In addition to monitoring the roadway, cameras are also used in vehicles to ensure that the driver is paying attention. One such system is DENSO’s Driver Status Monitor. This system detects a driver’s face angle, long-duration eye closure, drowsiness level, and head position by using a camera and IR LEDs for nighttime illumination. The computer in the system uses image recognition and processing technologies to detect the driver may be distracted or drowsy. The system is then able to produce a warning or adjust the direction of the side mirrors overall safety, comfort, and convenience.

DENSO DYNAMICS' Driver Status Monitor

 

Thermal Camera

Thermal cameras aren't a very popular option for driver assistance systems due to their cost. These systems are usually found in luxury vehicle brands such as BMW, Audi, and Mercedes. These thermal cameras use image processing to identify pedestrians and animals and alert the driver, even if lighting is not ideal.

Mercedes' Night View Assist

FLIR manufactures the PathFindIR II system that incorporated a rugged camera and image processing into one system. The pathfinder system has a range that far exceeds traditional high-beam lights and can alert the driver if it detects a person or animal. FLIR gears this system towards trucking and first responder applications.

FLIR's PathFindIR II

The Future

Ten years ago, many of these systems would have been considered science fiction. Five years ago, many these safety systems were reserved for luxury vehicles. Today, these systems can be found in many inexpensive cars. These driver assistance systems are becoming very popular and are paving the way for self-driving cars. In the next 5 years, these systems will most likely be on every car sold to some extent. In 10 years, self-driving cars might just be the norm!

Google's self-driving cars are becoming more popular