boteye icon indicating copy to clipboard operation
boteye copied to clipboard

标定文件中参数含义

Open QLJX opened this issue 6 years ago • 4 comments

你好,我刚接触这方面内容,所以有不少问题想要跟大佬们请教一下: 问题一,标定文件中,大多数都是简写,我是小白所以希望大佬能帮忙解释一下各个参数的含义,Imu: accel_TK,accel_bias,gyro_TK,gyro_bias, accel_noise_var, angv_noise_var,D_T_I。Camera: D_T_C_l,D_T_C_r,cameraK_l, cameraK_r,dist_coeff_l,dist_coeff_r, img_size。 问题二,imu和camera之间的坐标变换矩阵又是如何进行确定的。 问题三,我想得到imu标定参数,包括1、加速度计测量噪声标准偏差。2、陀螺仪测量噪声标准偏差。3、加速度计偏置随机工作噪声标准偏差。4、陀螺仪偏置随机工作噪声标准偏差。5、重力量级。 问题四、我使用了本产品作为slam的输入,但是出现了跑飞的情况,即使摄像机不动,仍然会飞出很远,请问这是什么原因引起的。 再次感谢各位大佬对我进行指导。

QLJX avatar Sep 03 '18 13:09 QLJX

A1:

Imu:
corrected_accel = accel_TK * (raw_accel - accel_bias)
corrected_gyro = gyro_TK * (raw_gyro - gyro_bias)
accel_noise_var: the noise std ^2 
angv_noise_var: the noise std ^2
D_T_I: The transformation from {I}mu to {D}evice.

Camera: 
D_T_C_l: The transformation from {C}amera_left to {D}evice.  Note that in boteye, we set {D} to {Cl}
D_T_C_r: The transformation from {C}amera_right to {D}evice.
cameraK_l: camera left intrinsics.
cameraK_r: camera right intrinsics.
dist_coeff_l: [k1, k2, p1, p2, k3, k4, k5, k6] of camera left
dist_coeff_r: [k1, k2, p1, p2, k3, k4, k5, k6] of camera left
img_size: image size of the camera output (identical for both cameras).

mingyux avatar Sep 04 '18 20:09 mingyux

A2: Due to the sensor manufacturing, we simply assume D_T_C is identity. Although the translation can be ~1cm off. Technically, this assumption won't make any difference. If you really care, you can do IMU-camera calibration with Kalibr. although the wrapper is not provided at this moment.

mingyux avatar Sep 04 '18 20:09 mingyux

A3: These imu intrinsics are measured and then heuristically tuned for the IMU we use on boteye sensor. The parameters are not exposed at this moment.

mingyux avatar Sep 04 '18 20:09 mingyux

A4: Make sure you set the correct -sensor_type. Even w/ a bad calibration it should not fly away when static.

mingyux avatar Sep 04 '18 20:09 mingyux