Accessibility links

New Studio Yields Most Detailed Motion Capture in 3-D

  • George Putic

Sports coaches often use video cameras to analyze athletes’ movements in order to improve their performance. A new multi-camera studio developed at Carnegie Mellon University promises to bring video analysis to an unprecedented level.

In 1878, using 12 still cameras positioned along a racetrack, English photographer Eadweard Muybridge solved a much debated question: whether a galloping horse had all of its legs in the air at one point.

137 years later, using more than 500 cameras, scientists at Carnegie Mellon University captured the motion of a baseball batter’s swing in unprecedented 3-D detail.

In a two-story dome made of 20 hexagons, called the Panoptic Studio, 30 high-definition video cameras, plus 480 additional cameras, records the same motion from different angles.

Carnegie Mellon computer scientist Hanbyul Joo says a computer turns those images into detailed 3-D analysis of the motion.

“The main purpose of this system is to analyze very interesting dynamic movements or dynamic things such as a sports players' motion," said Joo.

At any given moment, the system captures more than 100,000 points of motion, requiring 120 computer hard drives, as just one minute of such video takes up about 500 gigabytes of memory.

A sophisticated algorithm identifies only videos from cameras that see the points relevant to the target.

Once those videos are integrated and converted into a full 3-D reconstruction of the movement, the algorithm creates a detailed pattern of the motion.

“Using our system, we can compare those movements, so we can see how to teach the right motion to people," said Joo.

Scientists say the Panoptic Studio can be useful for analyzing and correcting any kind of movements or behavior.

As for large sports arenas and other events, researchers say they may be able to develop an algorithm that uses the same technique by capturing videos from hundreds of spectators’ cameras.