What is Motion Capture and how does it work?

Motion Capture (often called “mocap”) is about capturing motion and transforming it into digital information that computers can further process. That way, people can be “real-time” placed in completely different environments, or people can completely change their appearance and character. The technology is often used in the film and gaming industry to produce various special effects. See examples in this movie clip .

In INN MoCap, movements are recorded optically by 16 cameras. The cameras only care about reflections. Therefore, suits are used where so-called markers are attached. These markers are retroreflective, ie they send light directly back to the source (180 degrees). The cameras emit IR rays and thus get these returned where there are markers.

Why are so many cameras needed? Only one camera is required to detect movement. But to detect motion in a 3D volume, you must have at least two – otherwise the cameras would have no sense of depth. All cameras know their relative location to the others, so they together form an image of the cursor’s exact location in the room at all times. 16 cameras provide increased precision and they act as backups for each other if some markers fall outside.

Technical Specifications INN MoCap

  • 7 x 8 meter size
  • Mocap resolution 420Hz @ 5MP – up to 2000 Hz at lower resolution
  • 2 x RGB-kameraer 1080p @ 60 FPS / 720p @ 120 FPS
  • Sync to other camera and audio equipment
  • All data is tagged with the same sync
  • Optical detection using 16 IR cameras
  • Retroreflective marker sets
  • Can record up to 4 actors at a time
  • 2 “facial riggs” – Cara lite