ST Tech Improves Driver Monitoring

Article By : Nitin Dahad, EE Times

New image sensors optimize performance in near-IR range

LONDON — STMicroelectronics has introduced two new automotive global shutter image sensors for automotive in-cabin driver monitoring enabling high dynamic range and low noise where crosstalk is minimized even at near-infrared illumination.

ST’s new VG5661 and VG5761 are intended for high-end computer vision applications in automotive and industrial machine vision, with in-pixel linear high dynamic range. In automotive, they enhance monitoring of vehicle occupants by capturing the scene as illuminated from the camera, eliminating unpredictable external effects such as sunlight or street lighting. Their image quality sharpens the responses of driver-monitoring systems, especially under near-infrared illumination close to 940 nm, and enables new features such as assessing driver attention, passenger comfort, or child behavior.

The new sensors use ST’s automotive global shutter technology, which minimizes the illumination power consumption, even in high dynamic range mode.

The sensors were shown with automotive software company Jungo’s driver-monitoring solution CoDriver at the recent AutoSens Imaging conference and at electronica 2018. Jungo’s driver-monitoring software utilizes images from ST’s sensors to monitor the position and movements of all occupants, assessing the driver’s condition and accurately surveying the location and movements of other vehicle occupants. The purpose of the demonstration with Jungo was to show how to improve interactions between autonomous and human drivers and how passenger monitoring can be used to enhance comfort and security.

Driver fatigue is thought to be a factor in up to 25% of auto accidents, so enhanced driver monitoring with image sensors can help reduce injuries and save lives. Good sensing accuracy can help autonomous driving systems assess a human driver’s fitness to take over any time during a journey, easing transitions between manual and autonomous driving modes for greater comfort and safety.

Image courtesy of STMicroelectronics.
Image courtesy of STMicroelectronics.

The European car safety rating system Euro NCAP’s 2025 Roadmap has proposed driver monitoring as the highest-priority primary safety feature. It is also a prerequisite for automated driving.

The VG5661 and VG5761 are 1.6-Mpixel and 2.3-Mpixel automotive global shutter sensors. Unlike the rolling shutter, which continuously reads data directly from pixels one row at a time, global shutter captures the data at all pixels simultaneously.

ST says that it has created a unique automotive global shutter pixel with two memory cells while keeping a small pixel size of 3.2 μm, resulting in compact sensors and higher resolution that capture sharp, crisp images in challenging conditions. Two memory zones allow double-image storage, enabling linear high dynamic range up to 98 dB or background removal without lag effects and with no need for additional processing by the host system. This offloads the host processor and reduces instances of correction artifacts. In addition, high dynamic range and high modulation transfer function (MTF) at near-infrared wavelengths further minimizes interference from natural light sources.

The VG5661 and VG5761 are supplied in standard BGA packages or as bare die for direct integration in automotive OEM systems produced in high volumes. They are qualified to AEC-Q100 Grade 2 and include complex safety integrity features as required for an ASIL-B camera system in accordance with the automotive safety standard ISO 26262. The sensors are currently sampling, and ST is working with lead customers to facilitate adoption in new driver-assistance systems for next generations of vehicles.

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