Football + camera = touchdown!
Some football fans can never get close enough to the action – even if they happen to score front-row seats on the 50-yard line, they want to be right on the astroturf instead. For those fans, there’s BallCam.
The prototype, developed by Carnegie Mellon University in Pittsburgh and the University of Electro-Communications in Tokyo, features a camera embedded in a plastic foam football to record video while the ball is in flight.
BallCam obtains video while spiraling in flight. With the technology, football or other sports fans might someday see the game from the ball’s point of view.
“Imagine what it would feel like to watch, up close, the split-second drama of two athletes battling to take hold of a flying ball, or imagine the view of a home-run hit, from the baseball’s perspective, as it rockets away from the field,” said Kris Kitani, a researcher at Carnegie Mellon who created BallCam along
with Kodai Horita, Hideki Sasaki and Hideki Koike in Tokyo.
BallCam uses a single camera with a narrow field of view to generate a dynamic wide-angle video. The raw footage isn’t usable – unprocessed video taken from a camera inside a football, which can spin at 600 rpm, would be an unwatchable blur.
So the researchers developed a computer algorithm to convert the raw video into stabilized images. As the ball spirals, the camera records the dizzying array of upward and downward frames. The algorithm sorts out the skyward frames and discards them. The overlapping ground-view frames are then stitched together using special software to create a panoramic view.
These mini-panorama images of a football field were created by
stitching together frames captured with the BallCam prototype. An
algorithm creates watchable video from the frames caught by the camera
embedded in the spiraling ball.
Image distortion caused by the rolling-shutter effect (also known as video wobble), motion blur and lens distortion made it very difficult to accurately rectify the image, Kitani said. “We spent a lot of time [trying] to figure out the best way to generate a physically plausible sequence of images. In the end, we borrowed ideas from texture synthesis, used in the field of computer graphics, to cover over some of the inconsistencies in the images.”
This raw image frame captured by BallCam was to some extent corrected for distortion.
Further work is needed to eliminate distortion, and a faster camera sensor would reduce blurring, Kitani added.
The project, part of a larger research theme called Digital Sports, was presented this spring at the Augmented Human International Conference in Germany. “We spent a lot of time thinking about how technology could be used to both augment and create new sports,” Kitani said.
BallCam might be useful for TV or movie productions, or training purposes, but football leagues aren’t likely to approve such a device for regular games, the researchers say. Still, fans can hope.
MORE FROM PHOTONICS MEDIA