CODEWITHSUNDEEP
c++kinectopennipoint-cloud-library
athoesen
athoesen

Reputation: 63

How can I save a PCD file from a Kinect?

Preface: I'm fairly new to coding. Using Ubuntu 12.04 with latest PCL downloaded from their site (I believe PCL 1.7) I've successfully compiled and built the iograbber program listed here: http://pointclouds.org/documentation/tutorials/openni_grabber.php

I've looked up and down through the tutorials on pointclouds.org and there's nothing in there that explains how to add a few lines of code to save the current Kinect point cloud as a PCD file. In the "writer" tutorial it says

pcl::io::savePCDFileASCII ("test_pcd.pcd", cloud)

But this is simply to save the random example points. I want to execute the PCD saving with a keystroke, like pressing the spacebar. I know people have done this before but I cannot find example code. Can anyone point me in the right direction?

Upvotes: 4

Views: 7520

Answers (3)

Shubodh Sai
Shubodh Sai

Reputation: 41

This is an ideal solution for anyone working on ROS. So I divided the solution into two parts - one, storing it as ROS bag files (a handy tool for storing any kind of data from ros topics) and two, writing rosbag files to pcd files. This is really simple now.

(References: http://wiki.ros.org/Bags)

A) STORING DATA in BAG files. (ROS file type)

First store the data (any kind of data can be stored) as ROSBAG. ROSBAG just records data from topics.

1.To start using kinect, open a terminal and run

 $roslaunch kinect2_bridge kinect2_bridge.launch publish_tf:=true

This will let ROS system start getting data from kinect. You should see the system starts and stops with "waiting for clients to connect".

2.To view the point cloud, open a new terminal. Run

$ rosrun kinect2_viewer kinect2_viewer sd cloud

And you will see a new window pop up with a point cloud view. Here's link explaining the parameters for kinect2_viewer function: https://github.com/code-iai/iai_kinect2/tree/master/kinect2_viewer

3.To record the data,in a new terminal run

$ rosbag record -O pcl_sample1.bag -a

Here "-a" means you will subscribe to all available ros topics and record data from them. After you think the data is enough you can stop it by ctrl-C. The data will be stored in a .bag file, here name.bag. More settings can be found here:http://wiki.ros.org/rosbag/Commandline#record

Now unplug kinect. The bag file has data of all the topics which were run by launching kinect2_bridge. Now you can use the data from topics as if kinect was actually plugged in.

4.To play back the data, you need to stop the program in the first terminal (the launch file). Then you run

$ roscore

This will start a ROS server. Then in the other terminal, run

  1. Play the bag file:

    $ rosbag play pcl_sample1.bag

This will let ROS system play back the data you just recorded as if the device is still working. You can then use kinect2_viewer to see the data i.e.:

  1. Run any commands Kinect was actually plugged in.

    $ rosrun kinect2_viewer kinect2_viewer sd cloud

Note: If you want to record specific topics, visit http://wiki.ros.org/Bags.

B) CONVERTING BAG TO PCD Files: (It is just one command now.)

Writing appropriate topics to respective folders:

rosrun pcl_ros bag_to_pcd pcl_sample1.bag /kinect2/sd/image_color_rect src/

rosrun pcl_ros bag_to_pcd pcl_sample1.bag /kinect2/sd/image_depth_rect src/PCD\ Files/

Upvotes: 2

juliean angeles
juliean angeles

Reputation: 1

i had the same problem, but i got a solution.

In this code:

     void cloud_cb_ (const pcl::PointCloud<pcl::PointXYZ>::ConstPtr &cloud)
 {
   if (!viewer.wasStopped())
     viewer.showCloud (cloud);
 }

You have to add this line

pcl::io::savePCDFileASCII ("test_pcd.pcd", *cloud);

like this

 void cloud_cb_ (const pcl::PointCloud<pcl::PointXYZ>::ConstPtr &cloud)
 {
   if (!viewer.wasStopped())
   {
       viewer.showCloud (cloud);
       pcl::io::savePCDFileASCII ("test_pcd.pcd", *cloud);
   }
 }

It will slow the .exe, but you can try to put thi line in other part in the program

Upvotes: -1

api55
api55

Reputation: 11420

Using the same tutorial, you can add in

 void cloud_cb_ (const pcl::PointCloud<pcl::PointXYZ>::ConstPtr &cloud)
 {
   if (!viewer.wasStopped())
     viewer.showCloud (cloud);
 }

The line you wrote before, in the callback (function that receives the point cloud from the grabber), to have the following

 void cloud_cb_ (const pcl::PointCloud<pcl::PointXYZ>::ConstPtr &cloud)
 {
   if (!viewer.wasStopped()){
     viewer.showCloud (cloud);
     pcl::io::savePCDFile ("test_pcd.pcd", cloud);
   }
 }

This code should save the cloud that you are visualizing. If you are not visualizing the point clouds leave a comment please.

Note: you may also use 

pcl::io::savePCDFile ("test_pcd.pcd", cloud, true);

to save in binary mode that is a lot faster (but you may not read the file in text editors)

Hope this helps

Upvotes: 2

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