Running ROS Openni Tracker (Offline) with Recorded data '.oni' files

It is always more convenient to run the tracker on a recorded data.  I recorded an '.oni' file using Openni Sample 'NiViewer'. Initialized the Context manually rather than from the 'xml' file.

You need to make the following changes in your openni_tracker.cpp

Note:
I had created a ros package mimicking the openni_tracker {i.e with same dependencies}. Then i created an Eclipse project for it. It makes debugging and changing the code easier.



// Declare .oni player

xn::Player   g_Player;  




Instead of

/*
    string configFilename = ros::package::getPath("openni_tracker") + "/openni_tracker.xml";
    XnStatus nRetVal = g_Context.InitFromXmlFile(configFilename.c_str());
    CHECK_RC(nRetVal, "InitFromXml");

*/


    // added for Reading '.oni' file

    XnStatus nRetVal = g_Context.Init();
    CHECK_RC(nRetVal, "Init");
    nRetVal = g_Context.OpenFileRecording("your .oni file", g_Player);
    if (nRetVal != XN_STATUS_OK)
    {
    printf("Can't open recording %s\n", xnGetStatusString(nRetVal));
    return 1;
    }

• make
•  run openni_tracker
• rosrun rviz rviz 

Hopefully you will see the skeleton.

Following video shows ros openni tracker on recorded data :)

Running OpenNi tracker on ROS Bag files/ Subscribed Depth topics
/ / OpenNI Context
xn::Context g_context;
g_context.Init ();
// OR initialize from an XML file
nRetVal = nRetVal = xnLogInitFromXmlFile(SAMPLE_XML_PATH);
/ / Depth generator
xn::DepthGenerator depth_generator;
depth_generator.Create (g_context);
/ / Mock depth generator
xn::MockDepthGenerator g_mock_depth;
g_mock_depth.CreateBasedOn (depth_generator, "the mock-depth" );
/ / Create user generator using mock depth generator
xn::Query g_Query;
g_Query.AddNeededNode ( "mock-depth" );
xn::UserGenerator g_user;
g_user.Create (g_context, & g_Query);
//following runs in a while loop
while (ros::ok())
{
/ / Update data
g_context.WaitOneUpdateAll (depth_generator);
/ / Get original depth map
xn::DepthMetaData depthMD;
depth_generator.GetMetaData (depthMD);
/ / Make data writable and modify
depthMD.MakeDataWritable ();

/ / Modify data ....
//write a function which changes the depth data in your original depth map
transformDepthMD(DepthMetaData& depthMD)
/ / set the data of the mock-depth generator and pose will tracking will run on this
g_mock_depth.SetData (depthMD);
//rest of the code
.............
............
}
//the function for modifying depth data could like this
void transformDepthMD(DepthMetaData& depthMD)
{
          xn::Depthmap & depthMap = depthMD.WritableDepthMap ();
          for ( unsigned int y = 0; y < depthMap.YRes (); + + y)
                   for ( unsigned int x = 0; x < depthMap.XRes (); + + x)
                           depthMap (x, y) = 0; // replace the values of the depth map by recorded depth map
}