XQ20 stereo headset

Demo and values

Unit AUnit B

Head-worn stereo fisheye camera with a 6-axis IMU, recording to a memory card. Borme, a brand of Shenzhen Feikasi Industrial Co., Ltd., sells it as the XQ20. Two units were calibrated.

The 3D scene MVIS recovered from unit B.

Reprojection median0.14 px

cam0–cam1 baseline60.3 mm

cam0 td+5.74 ms

cam0 lever arm56.3 mm

No independent reference. These values show what MVIS solved, not how close they are to the truth.

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.

▶︎ Playcam0cam1Loading

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	−31.0, +1.2, +47.0	56.3	[−0.002, −0.005, +0.004]	+5.74	122° × 91°
cam1	+29.4, +1.3, +46.8	55.3	[+0.007, +0.002, +0.004]	+5.71	122° × 91°

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

Specifications

From the supplier's sheet
Cameras	2 × 1920×1200, H.265 MP4
Frame rate	30 or 60 fps on the sheet; about 30 Hz in these recordings
Field of view	123.6° on the sheet; axis not stated
IMU	6-axis, 300 or 600 Hz on the sheet; 300.5 Hz measured
Storage and interface	microSD up to 128 GB, or UVC; Type-C
Power	No battery
Weight	180 g with strap
From the seller's listing
Model number	XQ20
Cameras	2, dual 1080P, 2 MP, MP4
Lens	Fisheye
Frame rate	60 and 30 fps
Field of view	160°; axis not stated
Shutter	Global; not measured in these recordings
IMU	300 Hz; stamped at measurement end, 50 ppm, 32-bit µs
Measured in these recordings
Calibrated field of view	cam0 122° × 91° · cam1 122° × 91°
Not published
Open	Sensor part numbers

Dataset

Recordings	Unit A: 158 s, 4,736 frames. Unit B: 119 s, 3,573 frames
Format	MP4 plus per-segment IMU CSV, converted to EuRoC layout
Board	AprilGrid 6×6, tag 35.2 mm, spacing 0.3
Licence	CC BY-NC 4.0; commercial use by request
Hosted	Calibench community, xq20/ (access by automatic approval)

AprilGrid 6 × 6, 264 × 264 mm. Standard pattern, to scale

Detailed results

Lens Calibrated field of view

Calibrated field of view, horizontal × vertical. cam0: 122° × 91°, corners reach 64° from the axis · cam1: 122° × 91°, corners reach 64° from the axis

cam0 cam1

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 −0.79 ms

Scale as deviation from 1. Model: calyx. Gyro-to-accel time offset t_ga: −0.79 ± 0.73 ms.

Gyro scale x−2.34 %

Gyro scale y+0.12 %

Gyro scale z+0.03 %

Accel scale x+0.49 %

Accel scale y+0.26 %

Accel scale z−7.19 %

−8 %0+8 %

Timing cam0 td +5.74 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	601.80
fy px	601.71
cx px	965.21
cy px	632.15
k1	0.22812
k2	0.50495
k3	−0.48030
k4	0.17579
Lever x mm	−30.96
Lever y mm	+1.20
Lever z mm	+47.01
log(R) rad	[−0.0020, −0.0047, +0.0036]
td ms	+5.739
Reprojection px	0.184
cam1
fx px	601.49
fy px	601.48
cx px	952.61
cy px	563.74
k1	0.23534
k2	0.49056
k3	−0.46937
k4	0.17021
Lever x mm	+29.38
Lever y mm	+1.27
Lever z mm	+46.78
log(R) rad	[+0.0070, +0.0016, +0.0041]
td ms	+5.713
Reprojection px	0.173
IMU
t_ga ms	−0.79 ± 0.73

Limits

• No independent reference. These values show what MVIS solved, not how close they are to the truth.
• Unit A lever z sits about 25 mm above unit B, beyond the roughly 10 mm uncertainty for this motion. This is still open.
• The listing says 1080P and 160°, and the supplier's sheet says 1920×1200 and 123.6°. These recordings are 1920×1200. The listing's shutter value wasn't tested here.
• Accel z scale stays near 0.93 to 0.94 because z barely sees gravity in this motion, so it isn't a sensor property.

How it was run

• cam0 at 30 Hz, cam1 at 10 Hz, t_ga on, camera intrinsics free. Batch of 2026-11-03.