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Turn digital faces into a smooth video

U. WASHINGTON-SEATTLE (US) — Computer engineers have created a way to take hundreds—or even thousands—of digital portraits and in seconds create an animation of a person’s face.

The tool can make a face appear to age over time, or choose images from the same period to make the person’s expression gradually change from a smile to a frown.
The researchers were inspired, in part, by people who snap a photo of themselves each day and then align them to create a movie where they appear to age onscreen. They sought an automated way to get the same effect.

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“I have 10,000 photos of my 5-year-old son, taken over every possible expression,” says co-author Steve Seitz, a University of Washington professor of computer science and engineering and engineer in Google’s Seattle office. “I would like to visualize how he changes over time, be able to see all the expressions he makes, be able to see him in 3-D or animate him from the photos.”

Lead author Ira Kemelmacher-Shlizerman, a postdoctoral researcher in computer science and engineering, presented the research at the meeting of SIGGRAPH, the Special Interest Group on Graphics and Interactive Techniques.

“The vast majority of photos include faces—family, friends, kids, people who are close to us,” Kemelmacher-Shlizerman says.

The new project is in the same spirit as earlier research that automatically stitched together tourist photos of buildings to recreate an entire scene in 3-D. That work led to Microsoft’s Photosynth.

Faces present additional challenges, Kemelmacher-Shlizerman says, because they move, change, and age over time.

Luckily, face detection technology is improving. Picasa and iPhoto added face-recognition tools a few years ago; Windows Live Photo Gallery and, most recently, Facebook, can now automatically tag photos with people’s names.

“This work provides a motivation for tagging,” Seitz says. “The bigger goal is to figure out how to browse and organize your photo collection. I think this is just one initial step toward that bigger goal.”

The software starts with photos from the web or personal collections that are tagged with the same person. It locates the face and major features, then aligns the faces and chooses photos with similar expressions so the transitions are smooth. The tool uses a standard cross-dissolve, or fade, between images, which the researchers discovered can produce a surprisingly smooth transition that gives the appearance of motion.

An example video uses photos of a Google employee’s daughter taken from birth to age 20. The owner scanned the older photos to create digital versions, tagged them with the subject’s name and manually added the dates. The result is a movie in which the subject ages two decades in less than a minute.

For modern babies, who are digitally chronicled from before birth, such films will be much easier to create.

One version of the tool is already available to the public. Last year during a six-month internship at Google’s Seattle office, co-author Rahul Garg, a doctoral student in computer science and engineering, worked with Kemelmacher-Shlizerman and Seitz to add a feature called Face Movie to the company’s photo tool, Picasa.

The Face Movie version includes some simplifications to make it run more quickly. It also plays every photo tagged with the person’s name, but not necessarily in chronological order.

More news from the University of Washington: www.washington.edu/news/

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