Re: How to extend RTAB-Map Database information

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/How-to-extend-RTAB-Map-Database-information-tp3286p3288.html

Hi Chris,

If you are using ROS, this can be similar to User Data tutorial here: http://wiki.ros.org/rtabmap_ros/Tutorials/WifiSignalStrengthMappingUserDataUsage

In RTAB-Map library, Rtabmap::setUserData(int id, cont cv::Mat & data). If id is <=0, the data will be set to latest node in the graph. If you are going to set only a boolean, use cv:Mat(2,1,CV_8UC1) format (with dummy second row) to avoid rtabmap thinking that data is already compressed (one row CV_8UC1).

RTAB-Map doesn't save in the database exactly when a new node is created. The node stays in RAM until it is transferred to long-term memory or the application finishes (see this issue). You should then use Memory interface instead to access all nodes (those in RAM and those in database). Memory::getAllSignatureIds() return all Ids in the map (RAM and database), then with Memory::getSignatureDataConst(locationId, false, false, true, false), you can get back the userData.

Example with CoreWrapper.cpp

std::set<int> ids = rtabmap_.getMemory()->getAllSignatureIds();
for(std::set<int>::iterator iter=ids.begin(); iter!=ids.end(); ++iter)
{
   int id = *iter;
   SensorData data = rtabmap_.getMemory()->getSignatureDataConst(id, false, false, true, false);
   cv::Mat userData;
   data.uncompressDataConst(0, 0, 0, &userData)
   if(!userData.empty() && userData.at<unsigned char>(0,0) != 0)
      printf("Boolean is true for node %d!\n", id);
}

cheers,
Mathieu