Is the use of ToF cameras for safe driving a recent one? In fact, the 3D camera perception system based on ToF technology has had application cases as early as around 2015, mainly used for the gesture interaction function in the cabin. Previously, most driver monitoring systems used to detect driver fatigue used lower-cost conventional 2D visible light cameras (with IR infrared LEDs). 3D ToF has clear advantages when the application requires high distance accuracy as well as 3D imaging. The image processing depth accuracy of ToF cameras is higher than that of 2D cameras (video streaming). For example, at a distance of one meter, a ToF camera using a VCSEL (a type of optional light source) can typically achieve a distance accuracy of 1% (or 1cm), which is not possible with a 2D camera.
ToF camera technology route uniquely combines high-resolution depth and amplitude (grayscale) mapping to meet the needs of many interior sensing applications. Classification based on 3D depth differences without the need for color or grayscale contrast between the foreground and background enables identification of people and objects in many complex applications.
In addition, ToF cameras can provide two outputs simultaneously. The first is a depth image video stream, which outputs a pseudo-color image (where color represents depth) or a point cloud, which is then processed by detection algorithms and neural networks. The second is an amplitude image representing the strength of the reflected signal, aka a confidence image, a near-infrared 2D video stream, and is not affected by sunlight.
For driver monitoring systems, eye tracking is the core technology and key to ensuring system reliability and accuracy. The traditional method is mainly solved by software algorithms, but it is obvious that lower software development costs and higher performance can be achieved based on depth-sensing cameras. This means that safety function applications developed based on 3D ToF include driver fatigue detection functions, as well as occupant/child seat detection, enabling more precise airbag control. Using ToF cameras, several other safety features can also be implemented, such as steering wheel detection, line of sight, head pose, body pose detection, and advanced seat belt applications.
