Skip to main content

Concepts & glossary

Terms that come up across GI Labs capture devices.

  • Egocentric capture — recording from the wearer's first-person point of view.
  • Stereo (binocular) — two cameras capturing left and right views, enabling depth and wider coverage.
  • IMU — Inertial Measurement Unit. Measures motion and orientation; on EGO1 it tracks head pose.
  • MCAP — an open container format for timestamped, multi-channel recordings. It is self-describing: message schemas are stored inside the file, so any MCAP-compatible tool can read it without extra definitions. EGO1 recordings are .mcap files.
  • MCAP viewer — any app that can open .mcap recordings. One free option is Foxglove Studio (foxglove.dev), which decodes H.265 video natively.
  • H.265 (HEVC) — the video codec EGO1 uses to compress its camera streams.
  • Bitrate — how many bits per second the encoder spends on video. Higher means better image quality, a faster write rate to the SD card, and larger uploads.
  • Global shutter — a sensor that exposes every pixel of a frame at the same instant. Motion never distorts the frame's geometry, which is what makes it the right choice for fast movement and for pipelines that measure geometry. EGO1GS uses global-shutter cameras.
  • Rolling shutter — a sensor that exposes the frame one row at a time, top to bottom. Each frame is therefore a slight time-smear rather than a single instant, so quick camera motion makes straight edges lean and wobble (see shutter skew), and pulsed lighting can produce horizontal banding. EGO1 uses rolling-shutter cameras.
  • Shutter skew (also "jello") — the leaning and wobbling of straight edges in rolling-shutter footage during fast motion, caused by the top and bottom of the frame being exposed at different times. Global shutter eliminates it.
  • UVC — USB Video Class, the standard protocol that lets a device act as a plain USB camera.
  • Extrinsics / intrinsics — intrinsics describe a camera's internal optics (focal length, etc.); extrinsics describe where a camera or sensor sits relative to a reference frame. EGO1 uses the right camera (cam0) as the anchor for all extrinsics.
  • Quaternion — a compact, gimbal-lock-free representation of 3D orientation; EGO1 publishes fused head orientation as a quaternion.