LooperRobotics Insight 9

Demo and values

Hand-held 1Robot arm 1Robot arm 2

Sensor head from Looper Robotics with two global-shutter mono cameras, one rolling-shutter colour camera and a 400 Hz IMU. Hand-held and robot-arm recordings are shown separately.

The 3D scene MVIS recovered from hand-held recording 1.

Reprojection median0.24 px

cam0–cam1 baseline99.2 mm

cam0 td+1.22 ms

cam0 lever arm44.4 mm

No reference exists for these recordings, so the tables show repeatability, not accuracy.

Calibration process

The solved path of the rig around the board. Press Play or drag the bar to follow it, and use the buttons to change the view.

▶︎ Playcam0cam1cam2Loading

Board cornersRig path, darker is laterStartCurrent position

Solved rig

The solved rig in 3D, to scale. Tap a sensor for its values. Full screen lets you rotate and zoom. Grid squares are 20 mm.

3DFrontTopSide+−

To scale, from above and the front

From above

From the front

Camera	Lever x, y, z (mm)	Distance (mm)	log(R) (rad)	td (ms)	Field of view
cam0	−12.8, +38.3, +18.5	44.4	[+0.008, +0.003, −1.565]	+1.22	95° × 112°
cam1	−12.4, −60.9, +18.1	64.8	[+0.005, +0.003, −1.564]	+1.25	95° × 112°
cam2	−12.7, −11.3, +17.5	24.4	[+0.004, +0.009, −3.136]	−5.86	~151° × 82°

Solved by MVIS. Lever arms are in the IMU frame. Rotation is log(R), camera in the IMU frame.

Specifications

Published by the maker
Type	Spatial AI camera
From our catalog
Global-shutter cameras	2 × 544×640 mono at 20 Hz, hardware-synced stereo
Rolling-shutter camera	1 × 1088×1920 colour at about 4.3 Hz
Lens	Wide field of view; pinhole-equidistant fit
IMU	1 × 400 Hz, with stamps quantized to 2.5 ms
Measured in these recordings
Calibrated field of view	cam0 95° × 112° · cam1 95° × 112° · cam2 ~151° × 82°
Not published
Open	Sensor part numbers

Dataset

Hand-held	10 of about 66 s, 15.0 GB in all
Hand-held data	Calibench, looper-insight9/ (access by automatic approval). CC BY-NC 4.0, for the hand-held data, clip and figures; commercial use by request
Robot arm	2 of about 58 s, same program in both
Robot-arm data	Calibench community, looper-insight9/data/ (access by automatic approval). Everything except the board is blurred. CC BY-NC 4.0, for the data, clip and figures; commercial use by request
Board	AprilGrid 6×6, tag 55 mm, spacing 0.3, t36h11
Configs and results	Calibench community, looper-insight9/ (access by automatic approval)
Worked example	Looper SA16

AprilGrid 6 × 6, 412 × 412 mm. Standard pattern, to scale

Detailed results

Lens Calibrated field of view

Calibrated field of view, horizontal × vertical. cam0: 95° × 112°, corners reach 70° from the axis · cam1: 95° × 112°, corners reach 71° from the axis · cam2: ~151° × 82°, corners reach 72° from the axis

cam0 cam1 cam2

Read from the calibrated lens fit at the image edges, through the principal point. ~ marks an axis past the range the corners reached, where the fit is extrapolated. Past the fit means an edge lies beyond where the fit holds, so no value is given.

IMU Gyro-to-accel offset −5.03 ms

Scale as deviation from 1. Model: calyx. Gyro-to-accel time offset t_ga: −5.03 ± 0.02 ms.

Gyro scale x−0.06 %

Gyro scale y−0.26 %

Gyro scale z−0.46 %

Accel scale x−0.41 %

Accel scale y−0.33 %

Accel scale z+0.26 %

−8 %0+8 %

Timing cam0 td +1.22 ms

Offsets to scale, with t_imu = t_cam + td.

Full results Every solved parameter

Rotation is log(R) in rad, camera in the IMU frame.

Parameter	MVIS
cam0
fx px	332.94
fy px	332.94
cx px	271.89
cy px	318.57
k1	−0.02071
k2	0.01581
k3	−0.01915
k4	0.00461
Lever x mm	−12.78
Lever y mm	+38.27
Lever z mm	+18.53
log(R) rad	[+0.0083, +0.0025, −1.5655]
td ms	+1.221
Reprojection px	0.297
cam1
fx px	332.75
fy px	332.67
cx px	269.48
cy px	318.67
k1	−0.02056
k2	0.01677
k3	−0.01701
k4	0.00313
Lever x mm	−12.39
Lever y mm	−60.91
Lever z mm	+18.15
log(R) rad	[+0.0050, +0.0030, −1.5642]
td ms	+1.247
Reprojection px	0.313
cam2
fx px	772.29
fy px	772.40
cx px	959.70
cy px	535.51
k1	−0.02905
k2	−0.00425
k3	0.00253
k4	−0.00096
Lever x mm	−12.72
Lever y mm	−11.30
Lever z mm	+17.50
log(R) rad	[+0.0035, +0.0086, −3.1359]
td ms	−5.855
Reprojection px	1.437
Readout ms	+32.37
IMU
t_ga ms	−5.03 ± 0.02

Across 10 hand-held recordings: median ± sd

cam0
Lever x mm	−12.35 ± 0.30
Lever y mm	+38.27 ± 0.34
Lever z mm	+18.09 ± 0.55
td ms	+1.323 ± 0.080
cam1
Lever x mm	−11.93 ± 0.28
Lever y mm	−60.55 ± 0.31
Lever z mm	+17.54 ± 0.60
td ms	+1.369 ± 0.086
cam2
Lever x mm	−12.31 ± 0.27
Lever y mm	−11.18 ± 0.29
Lever z mm	+16.84 ± 0.67
td ms	−5.755 ± 0.174
IMU
t_ga ms	−5.21 ± 0.10

Across 2 robot-arm recordings: median ± sd

cam0
Lever x mm	−12.98 ± 0.18
Lever y mm	+41.88 ± 0.08
Lever z mm	+15.04 ± 1.07
td ms	+1.312 ± 0.162
cam1
Lever x mm	−12.32 ± 0.11
Lever y mm	−57.34 ± 0.09
Lever z mm	+14.18 ± 1.07
td ms	+1.354 ± 0.156
cam2
Lever x mm	−12.63 ± 0.13
Lever y mm	−7.87 ± 0.10
Lever z mm	+13.79 ± 1.07
td ms	−3.915 ± 0.182
IMU
t_ga ms	−5.35 ± 0.28

Limits

• No reference exists for these recordings, so the tables show repeatability, not accuracy.
• Hand-held and robot-arm recordings are kept apart, not pooled. They were solved in different batches and may not come from the same unit.
• Lever arms differ by about 3 mm in y and z, 4.5 to 5 mm in all, between the two sets. The arm program rotates mostly about one axis, which leaves lever arms less well determined, so treat the arm's values with more caution.
• The colour camera's td differs by about 1.8 ms between the two sets, and the cause isn't established.
• Robot-arm repeatability rests on 2 recordings.

How it was run

• Camera + IMU with camera intrinsics free, t_ga on and the cam2 rolling-shutter readout estimated. Hand-held batch of 2026-11-02; robot-arm batch of 2026-11-04.