An image processing system that hides the position from which photos are shot may help protesters in repressive regimes avoid arrest, an Indian researcher says.

The inspiration for the technology came in 2007 when the government of Myanmar, formerly Burma, began arresting people who had taken photos of police violence against pro-democracy protesters, many of whom were monks, NewScientist.com reported Thursday.

"Burmese government agents video-recorded the protests and analyzed the footage to identify people with cameras," security engineer Shishir Nagaraja of the Indraprastha Institute of Information Technology in New Delhi said.

By examining the perspective of pictures subsequently published on the Internet, the police could determine who had taken them, he said. People taking such pictures need "location privacy" for their personal safety, Nagajara said, which inspired him to work with European colleagues to create a way of disguising the viewpoint from which a photographer takes the picture.

"We use a computer-vision technique called view synthesis to combine two or more photographs to create another very realistic-looking one that looks like it was taken from an arbitrary viewpoint," security researcher Peter Schaffer of the University of Luxembourg said.

The images can come from more than one source as long as they were taken at around the same time of a reasonably static scene from different viewing angles, he said.

Software then examines the pictures and generates a 3D "depth map" of the scene, from which a user can choose an arbitrary viewing angle for a photo to be posted online.

The image then goes through a "dewarping" stage in which straight lines like walls and curb angles are corrected for the new point of view, and "hole filling" in which nearby pixels are copied to fill in gaps in the image created because some original elements were obscured.

The result is pretty convincing, Schaffer said.

"There are some image artifacts but they are acceptable," he said.

The team said it intends to make the software open source.

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