realsense t265参数查询与释义

参考优秀贴：
Intel Realsense T265使用教程
修改vins-fusion中T265的相机模型文件

一、相机内外参

方法1 – 通过echo ～/info话题获取

含有相机信息的话题共有三个，分别为两个鱼眼相机以及一个IMU话题

鱼眼相机：

rostopic echo /camera/fisheye1/camera_info

header: 
  seq: 13
  stamp: 
    secs: 1705891756
    nsecs: 533158064
  frame_id: "camera_fisheye1_optical_frame"
height: 800
width: 848
distortion_model: "equidistant"
D: [-0.008032865822315216, 0.04197604954242706, -0.03984801843762398, 0.006671988870948553]     --- 畸变 k1,k2,p1,p2
K: [286.01019287109375（fx）, 0.0, 415.5975036621094(cx), 0.0, 286.28009033203125(fy), 388.86700439453125(cy), 0.0, 0.0, 1.0]
R: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
P: [286.01019287109375, 0.0, 415.5975036621094, 0.0, 0.0, 286.28009033203125, 388.86700439453125, 0.0, 0.0, 0.0, 1.0, 0.0]
binning_x: 0
binning_y: 0
roi: 
  x_offset: 0
  y_offset: 0
  height: 0
  width: 0
  do_rectify: False
---

IMU：

rostopic echo /camera/gyro/imu_info

data: [1.0019333362579346, 0.0, 0.0, 0.0020760896150022745, 0.0, 1.00546395778656, 0.0, -0.0007157127256505191, 0.0, 0.0, 1.0032858848571777, 0.0036664302460849285]
noise_variances: [5.148030140844639e-06, 5.148030140844639e-06, 5.148030140844639e-06]
bias_variances: [4.999999987376214e-07, 4.999999987376214e-07, 4.999999987376214e-07]
---

含义：

通过 rostopic hz +话题名查看话题频率

方法2 通过realsense命令

rs-enumerate-devices -c

使用该指令时不能通过roslaunch开启相机

• 相机基本信息：

Device info: 
    Name                          : 	Intel RealSense T265
    Serial Number                 : 	224622111947
    Firmware Version              : 	0.2.0.951
    Physical Port                 : 	4-2-3
    Product Id                    : 	0B37
    Usb Type Descriptor           : 	3.1
    Product Line                  : 	T200
    
Stream Profiles supported by Tracking Module
 Supported modes:
    stream       resolution      fps       format   
    Fisheye 1	  848x800	@ 30Hz	   Y8
    Fisheye 2	  848x800	@ 30Hz	   Y8
    Gyro	 N/A		@ 200Hz	   MOTION_XYZ32F
    Accel	 N/A		@ 62Hz	   MOTION_XYZ32F
    Pose	 N/A		@ 200Hz	   6DOF

• 鱼眼相机内参：
  PS：这样查找出来的内参与使用话题得到的内参数字有些差距

 Intrinsic of "Fisheye 1" / 848x800 / {Y8}
  Width:      	848
  Height:     	800
  PPX:        	415.597503662109
  PPY:        	388.867004394531
  Fx:         	286.010192871094
  Fy:         	286.280090332031
  Distortion: 	Kannala Brandt4
  Coeffs:     	-0.00803286582231522  	0.0419760495424271  	-0.039848018437624  	0.00667198887094855  	0  
  FOV (deg):  	112 x 108.8

 Intrinsic of "Fisheye 2" / 848x800 / {Y8}
  Width:      	848
  Height:     	800
  PPX:        	425.432495117188
  PPY:        	399.840911865234
  Fx:         	287.047485351562
  Fy:         	286.825103759766
  Distortion: 	Kannala Brandt4
  Coeffs:     	-0.0120016001164913  	0.050355289131403  	-0.046617429703474  	0.00880880374461412  	0  
  FOV (deg):  	111.8 x 108.7

• 运动内参：

Motion Intrinsic of "Gyro"（陀螺仪）	  MOTION_XYZ32F
Bias Variances: 	0.000000499999999  0.000000499999999  0.000000499999999  
Noise Variances: 	0.000005148030141  0.000005148030141  0.000005148030141  
Sensitivity : 
     1.001933       0.000000       0.000000       0.002076  
     0.000000       1.005464       0.000000      -0.000716  
     0.000000       0.000000       1.003286       0.003666  


Motion Intrinsic of "Accel"（加速度计）  MOTION_XYZ32F
Bias Variances: 	0.000099999997474  0.000099999997474  0.000099999997474  
Noise Variances: 	0.000066952452471  0.000066952452471  0.000066952452471  
Sensitivity : 
     1.015164       0.000000       0.000000       0.127814  
     0.000000       1.026080       0.000000      -0.609172  
     0.000000       0.000000       1.008137      -0.042595  

• 外参：
  外参为若干从A坐标系到B坐标系的旋转矩阵（33）与平移矩阵（13），例如：

Extrinsic from "Fisheye 1"	  To	  "Fisheye 1" :
 Rotation Matrix:
   1   0   0
   0   1   0
   0   0   1

 Translation Vector: 0  0  0  

列出的转移关系有：

from	to
Fisheye 1 /2	Fisheye 1
Fisheye 1 /2	Fisheye 2
Fisheye 1 /2	Gyro(陀螺仪)
Fisheye 1 /2	Accel(加速度计)
Fisheye 1 /2	Pose
Gyro	Fisheye 1 /2
Gyro	Gyro / Accel / Pose
Accel	Fisheye 1 /2
Accel	Gyro / Accel / Pose
Pose	Fisheye 1 /2
Pose	Gyro / Accel / Pose

PS:
from Fisheye 1 /2 to Gyro / Accel / pose的 旋转矩阵 Rotation Matrix 参数基本一致， Gyro / Accel 的平移矩阵Translation Vector 基本一致，其中x,y与 to pose的参数有差距，z轴与 to pose的基本一致：

Extrinsic from "Fisheye 1"	  To	  "Gyro" :
 Rotation Matrix:
  -0.999923         0.00248067       0.0121957     
  -0.00240702      -0.999979         0.00605006    
   0.0122104        0.00602023       0.999907      

 Translation Vector: 0.0106991715729237  2.57550709648058e-05  -0.000130651504150592  

Extrinsic from "Fisheye 1"	  To	  "Accel" :
 Rotation Matrix:
  -0.999923         0.00248067       0.0121957     
  -0.00240702      -0.999979         0.00605006    
   0.0122104        0.00602023       0.999907      

 Translation Vector: 0.0106991715729237  2.57550709648058e-05  -0.000130651504150592  

Extrinsic from "Fisheye 1"	  To	  "Pose" :
 Rotation Matrix:
   0.999923        -0.00248067      -0.0121957     
  -0.00240702      -0.999979         0.00605006    
  -0.0122104       -0.00602023      -0.999907      

 Translation Vector: -0.0322808921337128  6.38301862636581e-05  0.000139380805194378  

IMU之间参数关系 —>>>>

Extrinsic from "Pose"	  To	  "Gyro" :
 Rotation Matrix:
  -1   0  -0
  -0   1  -0
  -0   0  -1

 Translation Vector: -0.0215817205607891  -3.80751152988523e-05  8.72930104378611e-06  

Extrinsic from "Pose"	  To	  "Accel" :
 Rotation Matrix:
  -1   0  -0
  -0   1  -0
  -0   0  -1

 Translation Vector: -0.0215817205607891  -3.80751152988523e-05  8.72930104378611e-06  

Extrinsic from "Pose"	  To	  "Pose" :
 Rotation Matrix:
   1   0   0
   0   1   0
   0   0   1

 Translation Vector: 0  0  0 

二、发布的odom信息

查询odom信息与哪个坐标系保持一致：

使用TF树查看： rosrun rqt_tf_tree rqt_tf_tree

使用TF树不能清晰表示获得的坐标信息；

使用rviz axis：

使用rviz可以查看相机相关多个坐标系信息，需要注意的是 fixed frame需要选择一个相机的坐标系，使用 map 或者 world 都会报 没有frame的警告。

三、关闭t265回环检测

在启动roslaunch 文件中添加：

 <rosparam>
      /camera/tracking_module/enable_relocalization: false
  </rosparam>

或者：

 <arg name="enable_relocalization"     default="false"/>