▲ ST Global-Shutter Image Sensor Photograph (Source: STMicroelectronics)


Observing driver head movements to recognize signs of drowsiness and inattention

STMicroelectronics (ST) further enhances vehicle safety with a driver monitoring safety system.

ST announced on the 16th that it has released the latest Global-Shutter image sensor that supports Driver Monitoring System (DMS).

DMS protects the safety of occupants by continuously observing the driver's head movements to recognize signs of drowsiness or distraction and causing the in-vehicle system to issue a warning.

Traffic authorities estimate that about 95% of road traffic accidents are caused by human error, and that the majority of these could be prevented by using systems such as DMS.

In Europe, approximately 19,000 accident fatalities occurred in 2020, and a recently enacted law is set to make DMS mandatory for all new car platforms in Europe by 2024 and for existing model platforms by 2026.

The United States has a traffic accident fatality rate twice as high as this, and the National Transportation Safety Board (NTSB) recommends DMS for all semi-autonomous vehicles.

Eric Oseda, Senior Vice President and Head of the Imaging Subgroup at ST, stated, “Drivers may not realize that driving is unsafe due to fatigue or distraction. DMS protects all occupants and those traveling on the road by automatically detecting these issues and eliminating uncertainties. ST’s latest global-shutter sensors provide sensitivity, a compact size, and simplified DMS hardware, reducing overall system costs. This enables customers and partners to deliver high-performance, reliable DMS systems that meet legal expectations.”

The new global-shutter sensor VB56G4A utilizes ST's proprietary advanced 3D stacked back-illumination (BSI-3D) image sensor manufacturing technology. This product is smaller and more stable, while offering superior sensitivity compared to the existing front-illumination (FSI) sensors used in first-generation DMS.

Global shutter sensors offer significant advantages over rolling shutter images. They allow for simple synchronization with NIR illumination, improving power consumption in the lighting subsystem.

In addition, it achieves a high quantum efficiency (QE) of 24% at a near-infrared wavelength of 940 nm with a linear dynamic range of up to 60 dB. This allows for providing appropriate illumination to the sensor with a simple, low-power, invisible LED emitter.

Even when operating outside the visible spectrum, it ensures a consistent response during day or night driving or in bright or cloudy conditions.

The high QE of this sensor and a pixel size of only 2.6µm help optimize total power consumption and camera size. In addition, it integrates automatic exposure control functions for ease of use and simplifies application software design by minimizing system interaction with sensors.

ST is currently supplying samples of the new sensor to key customers and plans to proceed with mass production in early 2023 so that it can be adopted in 2024 model year vehicles.