Tuesday, October 16, 2007

New Tricks for Online Photo Editing

Continued from page 1

By Kate Greene

Fredo Durand, a professor of computer science at MIT, notes, "Perhaps the best thing about this technique is its simplicity. It is a very short algorithm, and it works very well. This is why people like Rsizr and others have been able to implement it so quickly."

While the seam-carving algorithm wasn't difficult to translate into Flash, Tsui says that it took a few iterations to optimize his version of the technology so that it would work quickly on the Web. He also modified it so that a user could expand or contract in both the horizontal and vertical directions at once. "The novel thing about Rsizr," he says, "is that it works in both directions simultaneously." Getting this to happen was a challenge, he says, because removing a seam from the vertical direction can affect a horizontal seam later. Tsui's software works by making educated guesses about the entire area around a pixel, estimating which pixels can be removed in both directions with the least amount of distortion to the picture.

Tsui says that he has received positive feedback from users about his product since its launch. He's now working with an image-hosting company called Image Shack to implement his approach to seam carving.

Avidan says that seam carving can be used for more than just still images. While he won't comment on his current work at Adobe, he says, "The next step will be applying [seam carving] to video." The benefit here is that any video could fit on any screen, no matter the size. Additionally, it could make low-definition video look better when viewed on a high-definition display by dynamically adding pixels.