With Wearable Cameras, Motion Capture Turns Inside Out

A breakthrough in motion capture techniques has now expanded its territory - by turning the cameras around, scientists have found a way to capture motion almost anywhere.

Scientists at Disney Research, Pittsburgh (DRP) and Carnegie Mello University (CMU) have developed the next generation of motion capture animation techniques, by placing 19 high definition video cameras on the actor. The outward-facing body-mounted cameras overcome the limit of traditional motion capture tech where movements of actors can be recorded only inside studios and then are translated into digital models.

With the new technique, cameras are mounted on the limbs and the trunk of actors, facing outward toward the surrounding environment. It can capture motions such as running outside or swinging on monkey bars, which would be difficult to capture with the traditional method.

"If you go outside the sun interferes with the system, also it's confined to close space," said Yaser Sheikh, assistant research professor in CMU's Robotics Institute. "This system you wear the camera and it can be done outside and over long stretches of space."

When the actors move, the cameras will record videos which then can be compared with reference images, and translated into the animated figure in a virtual 3D space. The wearable camera system enables film makers to reconstruct the relative and global motions of an actor. The process is called SfM, developed 20 years ago as a means of determining the three-dimensional structure of an object.

According to the press release by CMU, the technique requires a significant amount of computational power; a minute of motion capture now can require an entire day to process. Future work will include efforts to find computational shortcuts, such as performing many of the steps simultaneously through parallel processing.

The new technique was presented by Takaaki Shiratori, a postdoctoral associate at DRP, at Monday's SIGGRAPH 2011, the International Conference on Computer Graphics and Interactive Techniques in Vancouver.

"This could be the future of motion capture," said Shiratori.