Intel RealSense D435i
一、准备工作
1、Intel Realsense D435i、Ubuntu 18.04
2、已经安装好Realsense驱动
3、已经安装好VINS-Mono并且能运行数据集
二、修改参数
rs_camera.launch
- 修改部分参数【
rs_camera.launch】；
第一处，修改unite_imu_method如下，这里是让IMU的角速度和加速度作为一个topic输出
#64行50列
<arg name="unite_imu_method" default="copy"/>
第二处，修改enable_sync参数为true，这里是开机相机和IMU的同步
#52行50列
<arg name="enable_sync" default="true"/>
第三处，修改enable_gyro,enable_accel为true;默认不发布
<arg name="enable_gyro" default="true"/>
<arg name="enable_accel" default="true"/>
realsense_color_config.yaml
1、订阅的topic
#common parameters
imu_topic: "/camera/imu"
image_topic: "/camera/color/image_raw"
2、相机的内参，通过读取camera_info得到或者自己标定，采用以下命令可以读取厂家的camera_info，但与实际可能存在差距。
rostopic echo /camera/color/camera_info
3、IMU到相机的变换矩阵
IMU到相机的变换矩阵，默认0这里我根据注释的提示修改成2
# Extrinsic parameter between IMU and Camera.
estimate_extrinsic: 2 # 0 Have an accurate extrinsic parameters. We will trust the following imu^R_cam, imu^T_cam, don't change it.
# 1 Have an initial guess about extrinsic parameters. We will optimize around your initial guess.
# 2 Don't know anything about extrinsic parameters. You don't need to give R,T. We will try to calibrate it. Do some rotation movement at beginning.
#If you choose 0 or 1, you should write down the following matrix.
这里IMU和camera之间的外参矩阵建议使用Kalibr工具进行离线标定，也可以改成1或者2让估计器自己标定和优化。
4、IMU参数，这个需要对IMU的噪声和Bias进行标定，同时重力加速度对结果有影响。
#imu parameters The more accurate parameters you provide, the better performance
acc_n: 0.2 # accelerometer measurement noise standard deviation. #0.2
gyr_n: 0.05 # gyroscope measurement noise standard deviation. #0.05
acc_w: 0.02 # accelerometer bias random work noise standard deviation. #0.02
gyr_w: 4.0e-5 # gyroscope bias random work noise standard deviation. #4.0e-5
g_norm: 9.81 # gravity magnitude
5、realsense d435i说是已经做好了硬件同步所以不需要在线估计同步时差（但是用kalibr标定出来和在线估计出来都存在大概-0.06的时间差）
#unsynchronization parameters
estimate_td: 0 # online estimate time offset between camera and imu
td: 0.000 # initial value of time offset. unit: s. readed image clock + td = real image clock (IMU clock)
6、相机曝光方式应为全局曝光
#rolling shutter parameters
rolling_shutter: 0 # 0: global shutter camera, 1: rolling shutter camera
rolling_shutter_tr: 0 # unit: s. rolling shutter read out time per frame (from data sheet).
然后就可以运行了
roslaunch realsense2_camera rs_camera.launch
roslaunch vins_estimator realsense_color.launch
roslaunch vins_estimator vins_rviz.launch
报错：
[ WARN] [1652767456.813384298]: waiting for image and imu...
vocabulary_file/home/sfann/catkin_ws/src/VINS-Mono/pose_graph/../support_files/brief_k10L6.bin
loop start load vocabulary
OpenCV Error: Assertion failed (_mask.empty() || (_mask.type() == CV_8UC1 && _mask.sameSize(_image))) in goodFeaturesToTrack, file /build/opencv-L2vuMj/opencv-3.2.0+dfsg/modules/imgproc/src/featureselect.cpp, line 366
terminate called after throwing an instance of 'cv::Exception'
what(): /build/opencv-L2vuMj/opencv-3.2.0+dfsg/modules/imgproc/src/featureselect.cpp:366: error: (-215) _mask.empty() || (_mask.type() == CV_8UC1 && _mask.sameSize(_image)) in function goodFeaturesToTrack
BRIEF_PATTERN_FILE/home/sfann/catkin_ws/src/VINS-Mono/pose_graph/../support_files/brief_pattern.yml
/home/tony-ws1/output/pose_graph/ not exists, trying to create it
/home/tony-ws1/output not exists, trying to create it
/home/tony-ws1 not exists, trying to create it
Failed to create folder /home/tony-ws1
/home/tony-ws1/output/ not exists, trying to create it
/home/tony-ws1 not exists, trying to create it
Failed to create folder /home/tony-ws1
no previous pose graph
[feature_tracker-1] process has died [pid 8424, exit code -6, cmd /home/sfann/catkin_ws/devel/lib/feature_tracker/feature_tracker __name:=feature_tracker __log:=/home/sfann/.ros/log/2a718c1c-d5a7-11ec-a32c-000c298e2de6/feature_tracker-1.log].
log file: /home/sfann/.ros/log/2a718c1c-d5a7-11ec-a32c-000c298e2de6/feature_tracker-1*.log
[ WARN] [1652767552.186227336]: image discontinue! detect a new sequence!
new sequence
sequence cnt 2
[ WARN] [1652767557.666477363]: image discontinue! detect a new sequence!
new sequence
sequence cnt 3
[ WARN] [1652767601.168880999]: image discontinue! detect a new sequence!
new sequence
sequence cnt 4
[ WARN] [1652767626.179102064]: image discontinue! detect a new sequence!
new sequence
sequence cnt 5
[ WARN] [1652767632.880353309]: image discontinue! detect a new sequence!
new sequence
sequence cnt 6
[ WARN] [1652767632.908686706]: only support 5 sequences since it's boring to copy code for more sequences.
[FATAL] [1652767632.908739701]: BREAKPOINT HIT
file = /home/sfann/catkin_ws/src/VINS-Mono/pose_graph/src/pose_graph_node.cpp
line=77
[pose_graph-3] process has died [pid 8426, exit code -9, cmd /home/sfann/catkin_ws/devel/lib/pose_graph/pose_graph __name:=pose_graph __log:=/home/sfann/.ros/log/2a718c1c-d5a7-11ec-a32c-000c298e2de6/pose_graph-3.log].
log file: /home/sfann/.ros/log/2a718c1c-d5a7-11ec-a32c-000c298e2de6/pose_graph-3*.log
解决办法：
修改enable_gyro,enable_accel为true;默认不发布
<arg name="enable_gyro" default="true"/>
<arg name="enable_accel" default="true"/>
修改相机的图片大小相关参数，以及根据相机的内参矩阵K对相机的内参进行修改
image_width: 1280
image_height: 720
参考文献
https://blog.csdn.net/weixin_44444810/article/details/121252009?
https://blog.csdn.net/qq_41839222/article/details/86552367
