Reference calibrations¶

The public Trinet-BatchCalibrations repository has one reference calibration per hardware version (two for V3, one per lens).

Version	Product	Camera	File
V1	Trinet Mono (original)	mono, ~180° lens	`mono/V1/trinet_V1_batch_calibration.json`
V2	Trinet Mono (original)	mono, ~180° lens	`mono/V2/trinet_V2_batch_calibration.json`
V3	Trinet Mono	mono, ~180° lens	`mono/V3/trinet_V3_180deg_batch_calibration.json`
V3	Trinet Mono	mono, ~150° lens	`mono/V3/trinet_V3_150deg_batch_calibration.json`
V4	Trinet Mono	mono, ~150° lens	`mono/V4/trinet_pro_mono_V4_batch_calibration.json`
V5	Trinet Stereo	stereo, rolling shutter	`stereo-rs/V5/trinet_pro_stereo_V5_batch_calibration.json`
V6	Trinet Stereo GS	stereo, global shutter	`stereo-gs/V6/trinet_pro_stereo_gs_V6_batch_calibration.json`

Use the file for your version

Calibrations of different versions are not interchangeable — in particular the camera–IMU time offset differs between versions, and Stereo (V5) and Stereo GS (V6) calibrations differ even though both have a 70 mm baseline. See Which camera do I have?

Typical unit-to-unit spread¶

Version	Focal length (1 SD)	Optical centre (1 SD)	Relative rotation between eyes (median / 95th pct)	Baseline (1 SD)
V3 (~180°)	±3 px	±10–17 px	—	—
V5	±2 px	±30–40 px	0.45° / 1.2°	±0.4 mm
V6	±4 px	±30–65 px	0.7° / 1.6°	±0.8 mm

For stereo, 0.1° of relative rotation shifts the image by about 1 pixel — so for metric depth, rectify with the unit's own factory calibration.

File format¶

All files are JSON. Units: pixels for intrinsics, metres for translations, seconds for time offsets. Every file repeats its conventions in a conventions block.

Mono (trinet-mono-calibration/1)Stereo (trinet-stereo-calibration/1)

{
  "format": "trinet-mono-calibration/1",
  "hardware": "Trinet Pro Mono",
  "hardware_version": "V4",
  "calibration_type": "batch",
  "lens": "~150° fisheye",
  "shutter": "rolling",
  "calibration_date": "2026-09-26",
  "conventions": { ... },
  "intrinsics": {
    "image_size": [1920, 1080],
    "model": "equidistant",
    "fx": 871.03, "fy": 872.44, "cx": 965.76, "cy": 551.46,
    "distortion": [k1, k2, k3, k4]
  },
  "T_cam_imu": [[...4x4...]],
  "timeshift_cam_imu_s": 0.00647,
  "imu": { "rate_hz": 400.25, "gyro_noise_density": ..., "gyro_random_walk": ...,
           "accel_noise_density": ..., "accel_random_walk": ... }
}

{
  "format": "trinet-stereo-calibration/1",
  "hardware": "Trinet Pro Stereo",
  "hardware_version": "V5",
  "calibration_type": "batch",
  "shutter": "rolling",
  "cameras": [
    { "intrinsics": { ...left eye, as mono... }, "timeshift_cam_imu_s": 0.0035 },
    { "intrinsics": { ...right eye... },         "timeshift_cam_imu_s": 0.0035 }
  ],
  "T_cam1_cam0": [[...4x4...]],
  "T_cam0_imu":  [[...4x4...]],
  "imu": { ... },
  "rolling_shutter": {                      // Stereo (V5) only
    "readout_time_s": 0.0318,
    "line_delay_s": 2.94e-05,
    "timestamp_reference": "centre image row, mid-exposure"
  }
}

Stereo GS (V6) has no rolling_shutter block; its timestamp_reference is mid-exposure.

The hardware field uses the internal model names: Trinet Pro Mono = Trinet Mono V4, Trinet Pro Stereo = Trinet Stereo, Trinet Pro Stereo GS = Trinet Stereo GS.

Calibrations are for 1920×1080 per camera (per eye on stereo). Conventions and tools: Use a calibration.

Versioning¶

Files are updated in place when a version's calibration is revised; every revision is recorded in the repository's changelog, and each file's calibration_date gives the date of its current revision.