Ensuring No Child Left Inside

April 1, 2022

Lindsay Brooke

A step-change in sensing precision is underway for vehicle interior applications, with increased capabilities spurred by new technology, customer interest in occupant safety and entertainment, and global regulations. Gentex is among those setting the pace in this fast-moving and hyper-competitive field, as it integrates its long experience in mirror-based opto-electronic systems and sensor fusion with the 2021 acquisition of Tel Aviv-based Guardian Optical Technologies and the 2020 purchase of Vaporsens.

The Holland, Mich.-based Tier 1 uses the term “holistic driver and cabin monitoring” to describe the interconnection of the two main development thrusts. There is discrete driver monitoring, vital for SAE Levels 2 and 3 of driving automation, with a subset of features aimed at driver distraction, drowsiness, weariness, sudden sickness, etc. And there’s the ‘holistic’ approach encompassing full-cabin monitoring using wide-field-of-view (WFoV) imaging as well as sensing of tactile surfaces and air quality involving particulates and airborne chemicals.

“As we develop these new capabilities with Guardian and Vaporsens, our scalable approach is opening up opportunities in the cabin, both for AVs and conventional vehicles,” Neil Boehm, Gentex’s CTO, told SAE Media. He noted that while each OEM has different motivations for applying in-cabin monitoring, a new Euro NCAP [New Car Assessment Program] mandate has the industry’s attention. The ruling plans to add driver/occupant monitoring to Euro NCAP’s 5-Star safety rating, beginning 2022. And it factors in child-presence detection – a response by policymakers to heatstroke fatalities suffered by children left alone in vehicles.

‘Fingerprinting’ the cabin

Tech veteran Boehm speaks proudly of what Guardian and Vaporsens have brought to the Gentex family, envisioning many potential use cases. Guardian was founded in 2015 to commercialize in-cabin monitoring systems and find solutions for fatalities and find solutions for hot-vehicle fatalities, through advanced occupant sensing and alerts. Its technology uses a high-resolution, IR-sensitive optical sensor that combines machine vision with micro-vibration and depth detection. The camera can detect movement as miniscule as one micron – a level of sensitivity that can pick up a baby’s breathing, a rate of change of breathing, and even its heartbeat, Boehm explained. Detecting that an impaired adult is about to pass out is also within the sensor’s capabilities.

“There is growing industry discussion about how to detect something in a vehicle seat, and is that something a person? If they’re covered up with blanket, you don’t get the visual features,” he noted. General Motors, Nissan and Hyundai have been early integrators of rear-seat occupant alert systems, using a variety of audio and visual reminders. Hyundai uses ultrasonic sensors mounted inside the headliners of two of its SUVs.

Vaporsens, based in Salt Lake City, pioneered nanofiber sensing technology through advanced sensor research from the University of Utah’s Materials Science Department. The sensing mechanism is based on a chemiresistor approach: Nanofiber sensors change electrical resistance in response to changes in a proximate chemical environment. When arranged in an array, the sensors’ combined responses form a unique signature or “fingerprint” for each target chemical. Nanofibers used as chemiresistor sensors can outperform other chemical sensor technologies in terms of operating conditions (humidity, temperature), recovery time, selectivity, and sensitivity, the companies claim.

AV vs. ADAS: How Gentex’s CEO sees it

During SAE Media’s visit to Gentex headquarters, we asked CEO Steve Downing about how he sees full vehicle autonomy playing out.

“Driver-assist systems, ADAS, are going to continue to be in the vast majority of vehicles sold, because a lot of people still want to drive themselves and experience the vehicle. But they want an assist system where necessary,” Downing said. “Seven years ago, the industry thought it was all about autonomous, with projections for 100 million cars a year. The reality is, we’re a lot closer to [SAE] Level 4 and that’s where the driver monitoring technology becomes really important. But I think there’s going to be a lot more bifurcation in the marketplace than what the industry thought initially.”

He noted that AVs for taxi or ride-sharing fleets will drive need for tech that supplements a vehicle’s autonomous operation.

“A lot of what we’re doing are creature comforts that would be valuable even when you’re driving the car,” he said. That means developing other sensing that will be needed to make that vehicle more useful and helpful to an OEM and to the consumer after Level-4 capability is achieved.

Modular engineering

At CES 2022, Gentex demonstrated its holistic driver-and-cabin monitoring system that also includes in-cabin infotainment capabilities using a full-size vehicle interior buck. The system’s core hardware is a compact (about 5 x 1.5 x 1 in./127 x 38 x 25 mm) module, still in prototype form, developed by Guardian. The module includes a camera and a laser projection system with infrared illuminators that create 3D imaging. The module can be packaged in the rear-view mirror (Gentex’s specialty, although packaging the laser has been a challenge) or disbursed in other locations, according to OEM preference.

“The system operates on a concept known as Structural Light,” Boehm explained. One form of Structured Light is Vertical Cavity Surface Emitting Laser (VCSEL), a type of laser diode that emits light from its surface, rather than its edge, but the Guardian tech uses “more of a single-mode light source,” he said. “Think of it like two lasers that have an optical ‘random’ pattern of dots in front of them. But unlike an iPhone camera VCSEL that is putting more than 30,000 dots on your face, this is going to do roughly 7,000 dots each in two regions. Besides creating the 3D depth map, it also can pick up micro movements based on how those dots change. So, when we catch the corner of a third-row seat, the breathing of a baby covered in a blanket can be picked up in the seat movement.”

Some companies are developing

radars for inside the vehicle, noted Boehm, who added that Gentex is doing the same benchmarking and evaluation. “There is still work to do on it,” he said. “But the technology is showing a lot of promise for detecting small movements that could be life savers. It’s really intriguing.”

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