In the realm of automotive safety, Driver Monitoring Systems (DMS) and Occupant Monitoring Systems (OMS) stand as crucial tools for ensuring passenger safety and well-being. Central to the functionality of these systems are various camera technologies, each tailored to meet specific monitoring needs. Let’s delve into the characteristics, applications, and advantages of each technology from the perspective of DMS and OMS. 

Driver Monitoring Systems (DMS) 

The significance of DMS has increased notably following the adoption of the European Union’s General Safety Regulations (GSR), set to take effect in June 2024. These regulations, primarily targeting active safety measures, are designed to proactively prevent accidents on the roads. Given the substantial contribution of human error to accident cause, there’s emphasis on monitoring driver behavior, through the soon-to-be mandatory functions Driver Drowsiness and Attention Warning (DDAW) and Advanced Driver Distraction Warning (ADDW).  

2D Cameras  

In DMS, primarily 2D NIR cameras are utilized to track facial features, eye movement, and eyelid closure, detecting signs of drowsiness, distraction, or other forms of impairment in real-time. 

  • Near-Infrared (NIR) Cameras: NIR cameras operate within the near-infrared spectrum, capturing images beyond the visible range of human vision. These cameras are known to perform well at any lighting conditions, making them ideal for driver monitoring applications running throughout day and night.  

3D Cameras 

In DMS, 3D cameras are not commonly found as the use cases are covered well within the capabilities of 2D cameras at a lower cost. However, they can provide accurate detection of driver’s (head) position and potential distractions. 


Occupant Monitoring Systems (OMS) 

With safety regulations setting the baseline for driver monitoring systems, the DMS concept has been expanded to include all occupants of the vehicle to ensure the safety and comfort of everyone. The (D)OMS set up, usually consists of one or two cameras installed in the center stack or around the rear-view mirror with a high field of view to capture all occupants in the vehicle and focus on passive safety and user experience use cases. Often those cameras are used to also monitor the driver in which case Driver and Occupant Monitoring are combined to DOMS and also cover active safety use cases. 

2D Cameras 

In OMS/DOMS, 2D cameras monitor both the driver and passengers, facilitating early intervention in case of driver impairment or health emergencies affecting any occupant. Besides optimal safety, features such as gesture control, face ID and expression recognition are implemented to provide occupants with a comfortable and pleasurable journey.  

  • Near-Infrared (NIR) Cameras: NIR cameras are employed to monitor both driver and passenger behavior, ensuring occupant safety and well-being. They excel in analysing occupants and objects in challenging lighting environments, enhancing overall safety. Novel machine learning approaches also make it possible to accurately extract 3D information from the 2D image which can be used for user experience and passive safety features. 
  • RGB-IR Cameras: RGB-IR cameras combine conventional RGB imaging with IR capabilities, enabling all OMS/DOMS features. In comparison to NIR cameras, they provide images with color which can be preferred for user experience use cases such as video calling.  

3D Cameras  

Since OMS/DOMS has a wider field of view and concerns both the driver and occupants within the vehicle, 3D cameras provide more value in a OMS/DOMS set up in comparison to DMS. 3D cameras provide spatial awareness of all vehicle occupants, facilitating the detection of potential hazards and ensuring the safety and comfort of everyone. Thus, being one of the possible options when it comes to passive safety use cases.  

  • Time-of-Flight (ToF) Cameras: ToF cameras provide precise depth perception, enabling accurate tracking of both driver and occupant movements within the vehicle. These cameras provide fast and accurate distance measurements, making them valuable for passive safety use cases such as adaptive airbag deployment. Moreover, user experience features using 3D information such as gestures can be implemented with high accuracy. 
  • Structured Light Systems: By triangulating the reflected light, structured light systems generate detailed 3D maps of the environment, facilitating object detection, localization and delivering similar benefits in terms of 3D information as ToF. 

Comparative Analysis 

  • DMS vs DOMS Scope:  
    • 2D cameras are primarily used in DMS set ups due to their cost-effectiveness and good performance across day and night. 
    • In contrast, both 2D and 3D cameras are utilized in OMS/DOMS to monitor not only the driver but also all vehicle occupants, ensuring comprehensive safety and well-being within the vehicle. Due to cost reasons, 2D cameras are still far more commonly used than 3D cameras. 
  • 2D vs 3D Camera Scope: 
    • Accuracy and Precision: 3D cameras, offer higher accuracy and precision in depth perception compared to 2D cameras. 
    • Versatility: While 3D cameras excel in certain scenarios, such as comprehensive spatial information, 2D cameras provide more detailed information due to higher resolutions making them very valuable for active safety use cases such as drowsiness and distraction. 
    • Cost and Complexity: 2D cameras are generally more cost-effective and easier to integrate into existing automotive systems, whereas 3D cameras require higher initial investment. 

In conclusion, while 2D cameras remain fundamental to both DMS and OMS/DOMS for monitoring driver behavior, the integration of 3D camera technologies can offer value for the capabilities of OMS/DOMS by providing spatial awareness. As automotive safety continues to evolve, both types of cameras will find application in advancing both driver and occupant safety systems.