STMicroelectronics offers new hybrid sensor for full interior vehicle monitoring

As advanced automotive markets start to mandate driver-monitoring systems (DMS), STMicroelectronics (ST) is equipping carmakers with the required technologies. While DMS promises greater road safety by assessing driver alertness, ST’s next-generation dual-image sensor monitors the full vehicle interior covering the driver and all passengers.

ST’s new image sensor is enabling new applications including passenger safety-belt checks, vital-sign monitoring, child-left detection, gesture recognition, and high-quality video/picture recording.

“The DMS market is growing at a double-digit pace. ST’s new image sensor is set to push that forward by enabling brands to create new services and deliver even greater value for vehicle users, leveraging complete in-cabin monitoring that covers multiple occupants,” said Eric Aussedat, executive VP, imaging sub-group GM, STMicroelectronics.

The new sensor, the VD/VB1940, delivers a cost-effective solution that combines the sensitivity and high resolution of infrared sensing with high dynamic range (HDR) color imaging in a single component. It can capture frames alternatively in rolling-shutter and global-shutter modes. With 5.1-megapixels, it captures the high-dynamic-range (HDR) color images needed for an occupant-monitoring system, in addition to the high-quality near-infrared (NIR) images typically captured by standard DMS sensors. DMS uses NIR imaging to analyze driver head and eye movements in all lighting conditions.

Offered in both bare wafers (VDB1940) and packaged in BGAs (VB1940), samples are available now and mass production is planned to meet demand for the model-year 2024 vehicles being designed now. .

Technical insights
The new automotive image sensor uses ST’s second-generation 3D-stacked back-side illuminated (BSI) wafer technology, which maximizes the optical area and on-chip processing in relation to die size. This lets the sensor perform sophisticated algorithms locally for optimal performance in color and NIR imaging, saving power and relieving demand for an external co-processor.

Algorithms performed on-chip include Bayer conversion and HDR merging for optimal image-quality and frame rate. On-chip Bayerization processing enables the user to reshuffle the color pixels of the RGB NIR 4X4 pattern into RGGB format compatible with a wide range of SoCs. In addition, local processing also handles independent color and NIR pixel-exposure optimization for optimum image quality in both modes, as well as smart upscaling to maximize NIR image resolution by capturing extra NIR information from RGB pixels.

The embedded processor also manages enhanced cybersecurity to ensure privacy in connected-vehicle applications, including mutual authentication and pairing of camera and electronic-control unit and video-stream authentication.

The sensor captures NIR images in global-shutter mode, which permits synchronizing with the infrared LED emitter to capture fast-moving scenes without motion blur. By also supporting rolling-shutter mode, which reads pixel data row by row, the VD/VB1940 provides optimum color-imaging performance. Leveraging the on-chip HDR-merge feature in rolling-shutter mode, the VB/VD1940 produces a 100dB full-resolution color image.