Introduction to ADAS Camera Systems
Introduction to adas camera systems
In recent years, the installation rate of Advanced Driver Assistance Systems (ADAS) in automobiles has been rapidly increasing. Looking at major manufacturers, these technologies are mainly concentrated in Level 2 to Level 3 autonomous driving. To achieve these functions, the number of cameras used in single-vehicle perception systems is typically five or more. For example, Tesla uses 8 cameras, Xiaopeng P7 has 14 cameras, WM Motor's W6 has 7 cameras, and the self-developed Zhiji automobile backed by Alibaba and SAIC has increased it to 15 cameras.
There are various ways to classify existing cameras: based on the number of CMOS lenses, we categorize them as monocular or binocular; based on the camera's field of view, we have wide-angle and fish-eye lenses. In this article, we will classify them based on the camera's installation position and different perspectives. They are generally divided into front view, rear view, surround view, side view, and interior view cameras.
Front View Cameras(ADAS)
Installation Position: Generally on the windshield or near the interior rearview mirror. These cameras, commonly referred to as front cameras, are used for forward driving assistance. They are primarily used to identify vehicles and pedestrians in front of the vehicle, with a field of view of approximately 45 degrees. The image sensor, along with the extended DSP and dual-core MCU, provides incoming video frames for image processing, monitors the road ahead, and enables functions such as Forward Collision Warning (FCW), Lane Departure Warning (LDW), and Adaptive Cruise Control (ACC). Additionally, emerging night vision cameras are typically included in this category.
Front view cameras can be either monocular or binocular. Binocular cameras offer better distance measurement performance but have more complex algorithms and higher prices. The number of cameras in front view systems is not fixed. For example, Tesla's configuration includes three cameras:
- Narrow field of view camera with a maximum monitoring distance of 250 meters
- Main field of view camera with a maximum monitoring distance of 150 meters
- Wide field of view camera with a maximum monitoring distance of 60 meters
Front view cameras are the core cameras for ADAS, covering distance measurement, object recognition, and road lane detection, thus requiring complex algorithms and higher thresholds.
Surround View Cameras(ADAS)
Installation Position: Front and rear vehicle emblems (or nearby) as well as a set of cameras integrated into the left and right side mirrors. Surround view cameras, also known as panoramic imaging systems, are used to identify parking lane markings, road conditions, and surrounding vehicle conditions. They utilize multiple camera images to create a 360-degree view around the vehicle. Due to the need for detecting surrounding sounds and situations, they are generally installed in the front of the vehicle, such as on the emblem or grille.
Currently, front view and surround view cameras are the most widely used types of cameras.
Side View Cameras(ADAS)
Installation Position: Left and right side mirrors or lower parts of the vehicle body. Side view cameras are mainly used for blind spot detection (BSD) and can provide either front or rear views depending on their installation position. Currently, most automakers choose to install them beneath the side mirrors, and in the future, they may replace traditional rearview mirrors.
Rear View Cameras(ADAS)
Installation Position: Generally installed on the trunk or rear windshield. Rear view cameras are primarily used during the reversing process to assist drivers in capturing images of the rear of the vehicle and enable parking assistance functions.
Installation Position: No fixed position, they can be found in the center of the steering wheel, above the interior rearview mirror, on the A-pillar, or integrated into the instrument display screen. Since current autonomous driving is only at Level 2 to Level 3, human driver intervention is still required. Therefore, Driver Monitoring Systems (DMS) have emerged as a solution in ADAS. Existing DMS solutions mainly utilize near-infrared cameras for AI recognition. These cameras are positioned in front of the driver and can capture complete facial information.
In addition, some manufacturers have extended the DMS system to OMS (Occupant Monitoring System), which can effectively prevent the forgetting of infants or children in the rear seats.
Of course, an ADAS sensor in a car is not limited to the above five types of cameras. To achieve redundant perception systems and ensure safety, automakers typically incorporate multiple sensor fusion technologies, including millimeter-wave radar, laser, ultrasound, etc. Moreover, it is highly likely that the number of cameras will increase.