Bosch’s Smart Visor Tracks the Sun While You Drive

The liquid crystal display blocks the sun in just the right spots

3 min read
Man in a car drives into the sun while the Bosch Virtual Visor blocks a distinct patch of sun from its liquid crystal display (LCD) screen.
Photo: Bosch

The automotive sun visor has been around for nearly a century, first affixed in 1924 as a “glare shield” on the outside of a Ford Model T. Yet despite modest advances—lighted vanity mirrors, anyone?—it’s still a crude, view-blocking slab that’s often as annoying as it is effective. 

Bosch, finally, has a better idea: An AI-enhanced liquid crystal display (LCD) screen that links with a driver-monitoring camera to keep the sun out of your eyes without blocking the outward view. The German supplier debuted the Bosch Virtual Visor at the recent CES show in Las Vegas. 

The Virtual Visor project began when Ryan Todd, a Bosch engineer in suburban Detroit, started daydreaming about what TV he wanted to buy during his sun-stroked commute: Eastbound every morning, westbound every afternoon. As explained by colleague and project engineer Jason Zink, Todd considered that while an OLED creates light, “an LCD actually blocks light in each pixel. He thought to himself, ‘Wow, I wish I could block out just this part of the sun, just like an LCD does.’” 

Todd pitched the idea that very day at an innovation meeting. More than three years later, Bosch is demonstrating a working prototype to manufacturers of both passenger cars and commercial vehicles, and hopes the technology will reach market within a few years. 

The visor links a simple, honeycomb-pattern LCD screen, reinforced with polycarbonate, with a driver-facing RGB camera and an electronic control unit (ECU) running an algorithm and AI program. 

The camera detects a driver’s face—eyes, nose, forehead—and the shadows the sun creates on the face. “So we understand the position and layout of the driver’s face on every frame that comes into the camera,” Zink says. 

AI tracks those facial landmarks, along with the sun’s relative position in the vehicle environment. Analyzing faces and shadows, the system essentially works backward, figuring out where light is entering the vehicle, no matter in which direction the car is headed. 

“The AI is a key enabler of the system,” Zink says. 

That AI, Zink says, employs neural networks and histogram of oriented gradients methods, with Bosch-trained models for those two AI techniques. Algorithms for shadow detection and to steer the screen are trained using domain-specific input data, e.g., real-world data from the vehicle. 

Difficult edge cases include faces being obscured by other objects: “Sunglasses don’t obscure much of the user’s face,” Zink says, but large hats, scarves, or medical-style facemasks all present challenges to algorithms that must locate the user, understand facial details, and analyze where shadows are being cast.

Bosch also plans to work with manufacturers to ensure the system meets all vehicle safety requirements. 

The actual sun-blocking, Zink says, is relatively easy: A patented algorithm pinpoints the driver’s eye position, and selectively darkens or lightens portions of the screen to ensure drivers aren’t blinded. The proprietary algorithm determines the shadows and where to block corresponding sections of the visor surface.

Zink says that 90 percent of the visor field remains transparent at all times, no matter the sun’s intensity or angle, which eliminates that annoying limbo where drivers constantly adjust their visor or try to peer under or around it. 

“You never have to take hands off the steering wheel to adjust the visor, or [take] your attention off the road,” Zink says. 

Glare from the sun can be more than a minor annoyance. According to one medical study, the risk of a life-threatening crash was 16 percent higher in bright sunlight than in normal daylight weather.

So why not just incorporate the LCD screen into the windshield? Well, aside from pesky issues of cost, or stones destroying the glass, there’s this: If the visor fails, the entire screen goes black. 

One cool bit is that, with driver-monitoring cameras now gaining traction in luxury cars, including the Cadillac CT6, to safely manage semi-autonomous driving functions, the Virtual Visor might become an affordable add-on: If a camera and computing power is already onboard, all that’s needed is the visor and more lines of code.

As for those aforementioned vanity mirrors, Fink says that manufacturers could still provide them via a secondary fold-down panel, if customers demanded them. Now, if Bosch can design a virtual mirror that makes me look like Tom Hardy, count me in.

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