Rig spec

6-cam head rig.

Six global-shutter cameras, two IMUs, and one hardware trigger: every camera exposes on the same 30 Hz pulse, so each frame across the rig belongs to one instant.

The OpenRobot 6C capture cap seen from the side — 6C Six global-shutter cameras on one cap: a forward stereo pair, a bottom pair for the hands, and one camera on each side.

camera IMU (ICM-42688-P), centred between the two lenses

Camera positions and angles are taken from the v3 case CAD. Forward stereo level with the head, bottom stereo 60° down for the hands, one camera on each side looking out at 90° and 20° down.

Get the sample data See the synced previews

Specifications

Layout and geometry

CamerasSix global-shutter cameras: a forward stereo pair, a bottom stereo pair, and one camera on each side

Forward stereoTwo cameras, level with the head, looking straight ahead; drives the trigger

Bottom stereoTwo cameras, 60° below the forward axis (30° from straight down), for the hands and close work

Side camerasOne on each side, looking out at 90°, tilted 20° down, for context

Stereo baseline60 mm per stereo pair (measured 60.2 mm on the calibrated unit)

SpacingThe bottom pair sits 29 mm below and 16 mm behind the forward pair; the two side cameras are 205 mm apart

Enclosure221 × 135 × 80 mm printed case (v3), one cable out of the cap

Imaging

Image sensorsonsemi AR0234 color global shutter, 1/2.6-inch, 1920 × 1200 active, 3 µm pixels

ShutterGlobal shutter on every camera: no rolling-shutter skew under head motion

OpticsM12 fixed-focus wide-angle lenses

Field of viewStereo pairs: approximately 112.1° horizontal / 79.8° vertical / 119° diagonal, ±1–2° unit variation. Side cameras: wide-angle, exact figure to be confirmed per lens

ExposureAuto exposure capped at 2 ms against motion blur; settable 0.25–10 ms per camera

Video output

Per camera1920 × 1200 @ 30 fps

Stereo layoutSide by side, left and right eye in one frame: 3840 × 1200 @ 30 fps

EncodingH.265/HEVC or H.264 on the camera; MJPEG also available

Frame cadence33.333 ms per frame, measured median 33 333 µs with 1 µs jitter

TimestampsPer-frame microsecond timestamps on the camera clock (stereo), host arrival time for every camera

Motion (IMU)

Count and placementTwo 6-axis IMUs, one behind each stereo pair, centred between its two lenses

DeviceTDK InvenSense ICM-42688-P (3-axis gyro + 3-axis accelerometer)

Output rateApproximately 500 Hz per IMU (measured 500–503 Hz), continuous with no gaps

RangesGyroscope ±1000 °/s, accelerometer ±4 g

Per sampleTri-axis gyro, tri-axis accel, temperature, and a microsecond timestamp on the same clock as the frames

Side camerasNo IMU

Synchronization

TriggerOne hardware FSYNC line at 30 Hz: the forward pair generates it, the other four cameras expose only on it

Left/right eyeSame-frame exposure inside each stereo pair, measured 0 µs offset

Pair to pairBoth stereo pairs on the same pulse; measured agreement within about 1 ms

Side camerasTriggered by the same pulse; their USB timestamps run 4 frames late, so the recorder ships a sync table

VerificationCross-camera alignment measured from image motion, not assumed: all six cameras line up at zero frame offset in every published session

Sync tablesync.csv: one row per trigger pulse with the matching frame index of every camera

Calibration

ModelPinhole with radial-tangential (Brown-Conrady) distortion

ContentsPer-eye intrinsics and distortion, stereo extrinsics, and rectification matrices, stored on the camera

AccuracyApproximately 0.36 px stereo reprojection RMS on a calibrated unit

NoteUnits ship with a factory blob; calibrate each stereo before using it for metric depth

Interface, power and recording

InterfaceUSB 2.0 High-Speed UVC, through one powered hub, single cable out of the cap to the receiver

Power5 V bus power; ≤320 mA per stereo pair, 1.6–2.0 A measured for the whole rig

Hub powerThe hub takes its own 5 V feed: on bus power alone it browns out when the fourth camera streams

ReceiverRaspberry Pi 5 recorder; frames are staged in RAM and drained to the card, so disk stalls cannot drop frames

Data rateAbout 14 MB/s for all six cameras, roughly 50 GB per hour

Measured reliabilityZero dropped frames on both stereo pairs across 12 minutes of published sessions; the side cameras skip isolated single frames, each marked in the sync table

Recorded data

Per cameraRaw video (H.264 Annex-B or MJPEG), frames.csv with per-frame timing and byte offsets, and imu.csv for the stereos

Per sessionsync.csv and sync_report.json, manifest.json, verify.json and audit.json (automatic quality checks), session log

Folder namesforward_stereo, bottom_stereo, right_mono, left_mono

Sample sessionsThe published samples were recorded on an earlier camera build: H.264 stereo at 3840 × 1200 and MJPEG side cameras at 1920 × 1080