University of Utah computer scientists have developed software that edits gigapixel images in seconds to produce preview images useful to doctors, intelligence analysts, photographers, artists, engineers and others.
By sampling only a fraction of the pixels in a massive image, it produces good approximations or previews of what the fully processed image would look like.
This allows massive images to be interactively edited and analyzed massive images – pictures larger than a gigapixel (billion pixels) – in seconds rather than hours, says Valerio Pascucci, an associate professor of computer science at the University of Utah.
"You can go anywhere you want in the image," says associate professor Valerio Pascucci. "You can zoom in, go left, right. From your perspective, it is as if the full 'solved' image has been computed."
The new software – Visualization Streams for Ultimate Scalability, or ViSUS – allows gigapixel images stored on an external server or drive to be edited from a PC or even a smart phone, Pascucci says.
In one example, the team combined a 3.7-gigapixel image of the entire Earth with a 116-gigapixel satellite photo of the city of Atlanta, zooming in on the Gulf of Mexico and putting Atlanta underwater there.
"It's just a way to demonstrate how an artist can manipulate a huge amount of data in an image without being encumbered by the file size," says Pascucci.
His team also used a camera mounted on a robotic panning device to take 611 photographs during a six-hour period. Together, the photos covered the entire Salt Lake Valley.
At full resolution, it took them four hours to stitch the mosaic of photos together into a 3.27-gigapixel panorama of the valley that eliminated the seams between the images and differences in their exposures.
But using the ViSUS software, it took only two seconds to create a "global preview" of the entire Salt Lake panorama that looked almost as good.
Pascucci says the method can be used to edit medical images such as MRI and CT scans, in 2D or even 3D.
It could also lead to more sophisticated computer games: "We are studying the possibility of involving the player in building their own [gaming] environment on the fly," says Pascucci.
It would be useful to intelligence analysts examining satellite photos, who might need to compare two 100-gigabyte satellite photos of the same location but taken at different times.