I have a small doubt, for example, if I have a PCL data structure of type pcl::PointCloud and I want to convert this into sensor_msgs::msg::PointCloud2 form, is there any function or way to achieve this? As far as I understood from PCL documentation regarding the function pcl::toROSMsg it only takes pcl::PointCloud as an argument
Hi, I have 2D-Lidar(lms511pro)x4 and I want to convert 2d lidars from laser_scan1,2,3,4 to PointCloud2 data. If I follow the way you do, I get pointcloud data though 4 laser scanners??
No, you would get 4 different PointClouds(one per each laser). We will publish a video showing how to combine several lasers into a single PointCloud very soon
Thank you very much for your reply. I will add one more question. What is the ROS version used in the video? I'm using a kinetic version and do it work fine if I follow the video?
Hi, very educative content. I love it. it help me alot, since I want to get the RPLIDARA3 since I want to use it in vertical configuration to make 3D maps. so in order to do it I need is the point cloud, but now do I array the point cluouds to build a 3D map? any Ideas? thanks for the tutorial.
By default when we convert the scan messages to point cloud data, it is in base_link frame, can you explain how we can get the point cloud values in map frame instead of 'base_link' frame so that we can use it for many other purposes ?
Use ROS TF to transform the data from one frame to another. Check this course to learn how to do it: www.theconstructsim.com/robotigniteacademy_learnros/ros-courses-library/tf-ros-101/
Hi,is it possible to "update" package dependencies? if i create a catkin package with my dependencies like your videos and after writing my code I discover i need more dependencies,how to do that? Thank you for your videos!!!
If you mean that you need more dependencies installed in RDS for your specific package, just send us an email to info@theconstructsim.com with the required dependencies and we will install them for you (and all other users)
Thanks for making such informative video. I am working on lidar based project and I am using RPlidar A1M8 360°. I want to make 3d point cloud using 2d lidar using ROS on raspberry pi 3. Please help me in this.
Hi, I have 2d urg 04lx-ug01 laser scanner(LIDAR) and ı want to convert this laser scanner from 2d to 3d . According to you, should ı do like this video (convert laserscan to point cloud ) or you said that we will share how to concatenate several laser scans into a single point cloud in order to get the 3d view ,should ı wait for that video ? please help me
Hi Ahmet, you should do as in this video. The video shows how to convert in 'real-time' the scans that the laser is generating into PointClouds. If your laser is not being moved by a motor (if the laser is fixed in the structure of your robot) then that is all you would need. Then this video is for you. However, sometimes, people mount the laser into a motor (like for example PR2) in order to use the laser to scan a 3D environment instead of a plane (2D). If that is your case, you should concatenate different readings of the laser taken from different positions of the laser motor. The result will still be a Point Cloud but it will contain all the lasers. How to do this last step is the matter of a future video. Hope this helps. Do not hesitate to ask again if not clear enough
Firstly ,thank you for your reply. My laser is being rotated by a motor but I couldn't even execute these steps that you are describing in this video. For example, - Since I am not use kobuki ,my rostopic list haven't kobuki/laser/scan . My rostopic list have /diagnostics , /rosout, /rosout_agg, /scan, /urg_node/parameter_description, /urg_node/parameter_updates . -Despite this situation, when ı run the code , I got an error like: Couldn't find executable named laser2PC below/home/ahmet/catkin_ws/src/laser2PC [rosrun] found the following ,but they're either not files,or not executables. - Have you made any changes in cmakelists.txt and package xml files. -I would love it if you take a video related to 3d image acquisition while laser rotating by a motor .
I see your situation. First, you must change the '/kobuki/laser/scan' topic of the video by you '/scan' topic. Second, due to the fact that you are not using the ROS Development Studio to develop your program, you need to do one step more for your program in order to be able to execute it. Go to the directory of your Python file and type 'chmod 777 ' This will provide executable permissions for your program Third, we will do that video of rotating scan next week. Staty tuned
Hello, I want to filter the PointCloud data. I'm using a development kit called JETSON TX1 and the system is slowing down because there are too many PointCloud data streams. I also want to reduce the number of points cloud data. How can I do that?
You have two options: 1- reduce the publication frequency of the pointcloud topic 2- just subscribe to the pointcloud topic when you want to get a pointcloud message then unsubscribe. The pointcloud publisher will not be publishing if nobody is subscribed, so you will be reducing a lot the load of your system
Hello there, I received the following messages, do you know why? [rosrun] Couldn't find executable named laser2pc.py below /home/ryan/catkin_ws2/src/laser2pc [rosrun] Found the following, but they're either not files, [rosrun] or not executable: [rosrun] /home/ryan/catkin_ws2/src/laser2pc/src/laser2pc.py Thank you
You can do that going to the location of the script and $ chmod +x laser2pc.py. Also, you can right click on the python file and properties>permissions and tick "allow executing file as a program"
![[ROS Q&A] 010 - How to import python modules from different ROS packages](http://i.ytimg.com/vi/9bgrzZ45HMA/mqdefault.jpg)
![[ROS Q&A] 010 - How to import python modules from different ROS packages](/img/tr.png)
![[ROS Q&A] 053 - How to Move a Robot to a Certain Point Using Twist](/img/1.gif)
I have a small doubt, for example, if I have a PCL data structure of type pcl::PointCloud and I want to convert this into sensor_msgs::msg::PointCloud2 form, is there any function or way to achieve this? As far as I understood from PCL documentation regarding the function pcl::toROSMsg it only takes pcl::PointCloud as an argument
Hi,
I have 2D-Lidar(lms511pro)x4 and I want to convert 2d lidars from laser_scan1,2,3,4 to PointCloud2 data.
If I follow the way you do, I get pointcloud data though 4 laser scanners??
No, you would get 4 different PointClouds(one per each laser). We will publish a video showing how to combine several lasers into a single PointCloud very soon
Thank you very much for your reply.
I will add one more question.
What is the ROS version used in the video? I'm using a kinetic version and do it work fine if I follow the video?
We are using Indigo, but it should work with no problem with Kinetic
Hi, very educative content. I love it. it help me alot, since I want to get the RPLIDARA3 since I want to use it in vertical configuration to make 3D maps.
so in order to do it I need is the point cloud, but now do I array the point cluouds to build a 3D map? any Ideas?
thanks for the tutorial.
is it possible to convert std_msg float32 to the point cloud?
By default when we convert the scan messages to point cloud data, it is in base_link frame, can you explain how we can get the point cloud values in map frame instead of 'base_link' frame so that we can use it for many other purposes ?
Use ROS TF to transform the data from one frame to another. Check this course to learn how to do it: www.theconstructsim.com/robotigniteacademy_learnros/ros-courses-library/tf-ros-101/
Sir, is there a way to use .png files of rgb and depth images and convert to point cloud.
how point cloud is different from laser scan??
Thank you it was very helpful !!
Hi,is it possible to "update" package dependencies? if i create a catkin package with my dependencies like your videos and after writing my code I discover i need more dependencies,how to do that? Thank you for your videos!!!
If you mean that you need more dependencies installed in RDS for your specific package, just send us an email to info@theconstructsim.com with the required dependencies and we will install them for you (and all other users)
Thanks for making such informative video. I am working on lidar based project and I am using RPlidar A1M8 360°. I want to make 3d point cloud using 2d lidar using ROS on raspberry pi 3. Please help me in this.
how to represent different scanned images togather at one simulation
Hi,
I have 2d urg 04lx-ug01 laser scanner(LIDAR) and ı want to convert this laser scanner from 2d to 3d . According to you, should ı do like this video (convert laserscan to point cloud ) or you said that we will share how to concatenate several laser scans into a single point cloud in order to get the 3d view ,should ı wait for that video ? please help me
Hi Ahmet,
you should do as in this video. The video shows how to convert in 'real-time' the scans that the laser is generating into PointClouds.
If your laser is not being moved by a motor (if the laser is fixed in the structure of your robot) then that is all you would need. Then this video is for you.
However, sometimes, people mount the laser into a motor (like for example PR2) in order to use the laser to scan a 3D environment instead of a plane (2D). If that is your case, you should concatenate different readings of the laser taken from different positions of the laser motor. The result will still be a Point Cloud but it will contain all the lasers. How to do this last step is the matter of a future video.
Hope this helps. Do not hesitate to ask again if not clear enough
Firstly ,thank you for your reply. My laser is being rotated by a motor but I couldn't even execute these steps that you are describing in this video. For example,
- Since I am not use kobuki ,my rostopic list haven't kobuki/laser/scan .
My rostopic list have /diagnostics , /rosout, /rosout_agg, /scan, /urg_node/parameter_description, /urg_node/parameter_updates .
-Despite this situation, when ı run the code , I got an error like: Couldn't find executable named laser2PC below/home/ahmet/catkin_ws/src/laser2PC [rosrun] found the following ,but they're either not files,or not executables.
- Have you made any changes in cmakelists.txt and package xml files.
-I would love it if you take a video related to 3d image acquisition while laser rotating by a motor .
I see your situation.
First, you must change the '/kobuki/laser/scan' topic of the video by you '/scan' topic.
Second, due to the fact that you are not using the ROS Development Studio to develop your program, you need to do one step more for your program in order to be able to execute it. Go to the directory of your Python file and type 'chmod 777 '
This will provide executable permissions for your program
Third, we will do that video of rotating scan next week. Staty tuned
ok
Even Though I haven't been succesfull running the code ,ı appreciate your help and patience.
Hello,
I want to filter the PointCloud data. I'm using a development kit called JETSON TX1 and the system is slowing down because there are too many PointCloud data streams. I also want to reduce the number of points cloud data. How can I do that?
You have two options:
1- reduce the publication frequency of the pointcloud topic
2- just subscribe to the pointcloud topic when you want to get a pointcloud message then unsubscribe. The pointcloud publisher will not be publishing if nobody is subscribed, so you will be reducing a lot the load of your system
Thank you very much
yo men, that sounds great!!!! ty so much
How can I convert point cloud to image data?
Thaaaaaaaaaaaaaaaanks so much , this videos helps me alot
Hello there, I received the following messages, do you know why?
[rosrun] Couldn't find executable named laser2pc.py below /home/ryan/catkin_ws2/src/laser2pc
[rosrun] Found the following, but they're either not files,
[rosrun] or not executable:
[rosrun] /home/ryan/catkin_ws2/src/laser2pc/src/laser2pc.py
Thank you
Yes. The reason of that message is that your Python file does not have execution permissions. Just assign permission for execution and that's it
You can do that going to the location of the script and $ chmod +x laser2pc.py.
Also, you can right click on the python file and properties>permissions and tick "allow executing file as a program"
how do i convert laser scan to pointcloud or even pointcloud2 to pointcloud?
You should use the PCL library. Check this link: wiki.ros.org/pcl/Overview
@@TheConstruct thanks