Motion Capture from Body-Mounted Cameras

Future movies may be using a different type of motion capture technique than we are used to today. rather using a camera to record the motion of a person or object, actors may be wearing numerous outward-facing cameras on a body suit.

The advantage: Motion capture can be accomplished outside and in large areas that are typically not accessible by traditional motion capture cameras that are used within studio environments today.

Researchers at the Carnegie Mellon Robotics Institute and Disney Research, Pittsburgh (DRP) are currently developing such a system. "Body-mounted cameras enable capture of motions, such as running outside or swinging on monkey bars, that would be difficult - if not impossible - otherwise," said Takaaki Shiratori, a post-doctoral associate at DRP.

A wearable camera system makes it possible to reconstruct the relative and global motions of an actor thanks to a process called structure from motion (SfM), Carnegie Mellon said. SfM is already 20 years old, but is now used to estimate the pose of the cameras on the person. In the initial tests, the technology employed 20 lightweight cameras on the limbs, and trunk of each person. Each camera was calibrated against a reference structure. When the actor moved, the system was able to automatically build a digital skeleton and estimate positions of cameras on that skeleton.

DRP said that the technology does not yet match the precision of traditional motion capture and will require higher resolution compact cameras and an enormous amount of computing horsepower. One minute of motion capture will take up to a day of computer processing, DRP said.