Monday, November 9, 2015

Bringing a bird’s eye view to a car near you

QNX and TI team up to enable surround-view systems in mass-volume vehicles

Paul Leroux
Uh-oh. You are 10 minutes late for your appointment and can’t find a place to park. At long last, a space opens up, but sure enough, it’s the parking spot from hell: cramped, hard to access, with almost no room to maneuver.

Fortunately, you’ve got this covered. You push a button on your steering wheel, and out pops a camera drone from the car’s trunk. The drone rises a few feet and begins to transmit a bird’s eye view of your car to the dashboard display — you can now see at a glance whether you are about to bump into curbs, cars, concrete barriers, or anything else standing between you and parking nirvana. Seconds later, you have backed perfectly into the spot and are off to your meeting.

Okay, that’s the fantasy. In reality, cars with dedicated camera drones will be a long time coming. In the meantime, we have something just as good and a lot more practicable — an ADAS application called surround view.

Getting aligned
Approaching an old problem from a
new perspective
. Credit: TI
Surround-view systems typically use four to six fisheye cameras installed at the front, back, and sides of the vehicle. Together, these cameras capture a complete view of the area around your car, but there’s a catch: the video frames they generate are highly distorted. So, to start, the surround-view system performs geometric alignment of every frame. Which is to say, it irons all the curves out.

Next, the system stitches the corrected video frames into a single bird’s eye view. Mind you, this step isn’t simply a matter of aligning pixels from several overlapping frames. Because each camera points in a different direction, each will generate video with unique color balance and brightness levels. Consequently, the system must perform photometric alignment of the image. In other words, it corrects these mismatches to make the resulting output look as if it were taken by a single camera hovering over the vehicle.

Moving down-market
If you think that all this work takes serious compute power, you’re right. The real trick, though, is to make the system affordable so that luxury car owners aren’t the only ones who can benefit from surround view.

Which brings me to QNX Software Systems’ support for TI’s new TDA2Eco system-on-chip (SoC), which is optimized for 3D surround view and park-assist applications. The TDA2Eco integrates a variety of automotive peripherals, including CAN and Gigabit Ethernet AVB, and supports up to eight cameras through parallel, serial and CSI-2 interfaces. To enable 3D viewing, the TDA2Eco includes an image processing accelerator for decoding multiple camera streams, along with graphics accelerators for rendering virtual views.

Naturally, surround view also needs software, which is where the QNX OS for Safety comes in. The OS can play several roles in surround-view systems, such as handling camera input, hosting device drivers for camera panning and control, and rendering the processed video onto the display screen, using QNX Software Systems’ high-performance Screen windowing system. The QNX OS for Safety complies with the ISO 26262 automotive functional safety standard and has a proven history in safety-critical systems, making it ideally suited for collision warning, surround view, and a variety of other ADAS applications.

Okay, enough from me. Let’s look at a video, hosted by TI’s Gaurav Agarwal, to see how the TDAx product line can support surround-view applications:

For more information on the TDAx product line, visit the TI website; for more on the QNX OS for Safety, visit the QNX website.

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