源码里的教程：
Using Custom Bag Files (or Real Robots)
Bag files (or real robots) must provide at least images for RatSLAM on topics //camera/image [sensor_msgs::Image] or //camera/image/compressed sensor_msgs::CompressedImage. Odometry may also be provided on topic //odom [nav_msgs::Odometry], or can be estimated using visual flow from the image data. Aside from the bag file, two other files are required: a config file and a launch file.
他这里提到的config文件和launch文件我自己写好了
下面的教程就看不懂了，请大佬解读一下
Creating a bag file
Loading a dataset into a bag file
The easiest way to tune RatSLAM is using an offline dataset. Any robot providing camera images as sensor_msgs/CompressedImage and odometry as nav_msgs/Odometry can be used. The images and odometry must be in the form /camera/image and /odom.
To convert topic names to the correct format run:
rostopic echo | rostopic pub /camera/image sensor_msgs/CompressedImage &
rostopic echo | rostopic pub /odom nav_msgs/Odometry &
Start recording into a bag file:
rosbag record -O .bag /camera/image /odom
Start the robot and collect the dataset. Press Ctrl-C at the terminal to finish recording.
请问你看的这个教程在哪里看的，我现在只能用ratslam跑数据集，不会调用USB摄像头来运行ratslam
这个就是要求录一个rosbag
由于ratslam代码中调用的是 sensor_msgs/CompressedImage & nav_msgs/Odometry
所以使用（rostopic echo | ）rostopic pub /camera/image sensor_msgs/CompressedImage &
（rostopic echo |） rostopic pub /odom nav_msgs/Odometry
两个命令将话题/camera/image和/odom 转换成sensor_msgs/CompressedImage & nav_msgs/Odometry。
然后运行rosbag record -O .bag /camera/image /odom
开始录就行了