ROS : laser_assembler
OS : Ubuntu 18,04 Distro : melodic
Hello guys,
im trying the laser_assembler but i have the following error :
[ERROR] [1627088238.325826329]: Client [/myassembler] wants topic /livox/lidar to have datatype/md5sum [sensormsgs/LaserScan/90c7ef2dc6895d81024acba2ac42f369], but our version has [sensor_msgs/PointCloud2/1158d486dd51d683ce2f1be655c3c181]. Dropping connection.
I am using livox mid 40, which topic list about laser os /livox/lidar.
The steps im trying to follow are the below:
1)roslaunch lasertopcl kaserassembler.launch 2)roslaunch loamlivox rosbag.launch 3)rosbag play bag.bag
The error happening when im try to play rosbag (step 3). I found some other posts here about different msgs versions, but i need help to fix it.
My launch file is :
and my .py file is :
Thanks in advance.
Asked by ManChrys on 2021-07-23 20:15:39 UTC
Answers
I'm responding to the original question: the error indicates your launch file has not correctly hooked up the topic names recorded in the bag file. You can use rosbag info to see the topics & message types inside the bag file.
Asked by Mike Scheutzow on 2021-07-24 10:11:40 UTC
Comments
im using the right topic and msgs i think
types: sensor_msgs/PointCloud2 [1158d486dd51d683ce2f1be655c3c181]
topics: /livox/lidar 6500 msgs : sensor_msgs/PointCloud2
Asked by ManChrys on 2021-07-24 10:22:42 UTC
Comments
i tried point_cloud_assembler instead of laser_scan_assembler.
my launch is now
when im running the launch file i have new error
Client [/my_assembler] wants topic /livox/lidar to have datatype/md5sum [sensor_msgs/PointCloud/d8e9c3f5afbdd8a130fd1d2763945fca], but our version has [sensor_msgs/PointCloud2/1158d486dd51d683ce2f1be655c3c181]. Dropping connection.
so i have to change PointCloud to Pointclkoud2. How can i do this ? i have to change inside the launch file the string remap from ="cloud" to remap from:cloud2" ? Is this the change or i have to do something more?
Asked by ManChrys on 2021-07-24 07:41:00 UTC
Please don't upload images of screen captures of text. You should copy/paste the actual text and format it using control-k.
Asked by Mike Scheutzow on 2021-07-24 10:08:47 UTC
What are you trying to accomplish? Your bag file appears to already have PointCloud2 messages.
Asked by Mike Scheutzow on 2021-07-24 10:43:46 UTC
i am using livox mid 40 lidar. So i record bag file or convert .lvx file to bag and i want to create a single pointcloud through this bag file. I tried
rosrun pcl_ros bag_to_pcd <input_file.bag> <topic> <output_directory>but it creates multiple pcd files (one for each frame). As i said i want a single pointcloud (ply, las, las) which i can use it in cloudcompare meshlab or something like that. I saw that cloud assembler its the solution thats why im trying to solve this . I dont know if there is a better way.Asked by ManChrys on 2021-07-24 10:48:12 UTC
I have no knowledge about pcd files. It seems like this topic now is quite far from your original question up above. Consider posting a new question asking for a methodology to get PointCloud2 into cloudcompare (or whatever tool you want to specify.)
Asked by Mike Scheutzow on 2021-07-24 11:40:49 UTC
ok thank you my friend.
Asked by ManChrys on 2021-07-24 11:43:08 UTC