Global shutter image sensor enables affordable and reliable driver monitoring systems
DMS solutions continuously monitor the head movements of the person sitting at the steering wheel to detect signs of fatigue or distraction. This enables the systems in the vehicle to generate warning signals to ensure the safety of the vehicle’s occupants. Traffic authorities estimate that about 95 per cent of road accidents are due to human error, and much of this could be avoided with DMS solutions or similar systems. The installation of a DMS will be mandatory for new vehicle platforms from 2024 and for existing model platforms from 2026 in Europe; in the US, the National Transportation Safety Board (NTSB) recommends the installation of a DMS in all semi-autonomous vehicles given.
The new VB56G4A global shutter sensor benefits from ST’s investment in the production of image sensors based on advanced BSI-3D (3D Stacked Back-Side Illuminated) technology. These not only offer higher sensitivity, but are also smaller, more energy-efficient and more reliable than conventional FSI (Front-Side Illuminated) sensors used in the first generation of strain gauges.
A global shutter image sensor offers great advantages over rolling shutter image sensors. By exposing all pixels of an image simultaneously, a global shutter sensor allows easy synchronisation with NIR illumination, improving the energy budget of the illumination subsystem. Apart from this, the new sensor achieves a high quantum efficiency (QE), reaching a value of 24 % in the near-infrared range at 940 nm, as well as a linear dynamic range of up to 60 dB. This means that a power-saving LED operating in the non-visible range is sufficient to provide sufficient illumination for the image sensor. Moreover, by operating outside the visible light spectrum, uniform behaviour is achieved during the day and at night, in bright sunlight as well as under overcast skies.
Combined with a pixel size of only 2.6 µm, the sensor’s high QE value helps optimise overall power consumption and camera size. The integrated automatic exposure control also makes it easier to use and simplifies the design of the application software, as interactions between the system and the sensor are kept to a minimum.
External connections include eight programmable general-purpose input/output (GPIO) pins and a dual-lane MIPI CSI-2 transmitter interface with up to 1.5 Gbps per lane. The sensor can operate at up to 88 frames per second (fps) at full resolution, and typical power consumption is 145 mW (at 60 fps).
The vendor is already supplying lead customers with samples of this image sensor. Mass production is scheduled to begin in 2023, allowing for introduction in 2024 model year vehicles.
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
