STMicroelectronics Launches Global Shutter Image Sensor for Driver Monitoring Safety Systems

According to foreign media reports, STMicroelectronics has announced the launch of a new global shutter image sensor for driver monitoring systems (DMS) to improve vehicle safety.

DMS continuously observes the driver's head movements to identify signs of drowsiness and distraction, enabling systems in the vehicle to generate warnings to protect the safety of occupants. The Department of Transportation estimates that approximately 95% of road traffic accidents are caused by human error, and many of these accidents can be avoided with systems such as DMS.

Image source: STMicroelectronics

“Some drivers may not realize that fatigue or distraction could make their car unsafe. DMS removes uncertainty by automatically detecting problems, protecting all occupants and others on the road,” said Eric Aussedat, Executive Vice President and General Manager of Imaging Group at STMicroelectronics. “ST’s latest global shutter sensors offer high sensitivity and are very compact, simplifying DMS hardware and reducing overall system costs. As a result, our customers and partners can deliver high-performance and reliable DMS systems that meet regulatory standards.”

The new global shutter sensor, the VB56G4A, leverages ST’s development resources in making advanced 3D-stacked back-illuminated (BSI-3D) image sensors, which are more sensitive, smaller, and more reliable than the traditional front-illuminated (FSI) sensors typically used in first-generation DMS.

Global shutter sensors offer additional advantages over rolling shutter imagers. By exposing all pixels to the image simultaneously, global shutter sensors can be easily synchronized with NIR illumination, improving the power budget of the illumination subsystem. In addition, the new sensor achieves high quantum efficiency (QE), reaching 24% at 940nm NIR wavelength, and a linear dynamic range of up to 60dB. As a result, even a simple low-power, invisible LED emitter can provide sufficient illumination for the sensor. Operation outside the visible spectrum also ensures consistent response when driving during the day or at night, and in bright or cloudy conditions.

The sensor's high QE combined with a 2.6µm pixel size helps optimize total power consumption and camera size. In addition, the integrated automatic exposure control simplifies use and simplifies application software design by minimizing system interaction with the sensor.

The sensor also offers flexible operating modes that help optimize system features and performance, including programmable sequencing of contextual 4 frames, illumination control output synchronized with the sensor integration cycle, input of an external frame start signal, automatic dark calibration, dynamic defective pixel correction, image cropping, and mirrored/flipped image readout.

External connections include eight programmable general-purpose I/O (GPIO) pins and a two-lane MIPI CSI-2 transmitter interface running at up to 1.5 Gbps per lane. The sensor can run at up to 88 frames per second (fps) at full resolution and consumes a typical power of 145mW at 60 fps.