[ros-users] Frame questions

[Dejan Pangercic]

Hey Todd,
what exactly is the question, you do not understand the code?
Can you post the whole h/cpp files?
Do you have some laser scan data in a bag file we could try the code on?

cheers,

On Wed, Mar 17, 2010 at 5:00 PM, Todd Anderson <tdansel88 at gmail.com> wrote:
> Hello, I am trying to use the point cloud on laser data... but the
> transform/frame stuff is messing with me.  I want to be able to get points
> with reference to the robot and points with reference to the fixed frame
> map.  Currently I am looking up the transform between base_laser_link and
> odom which outputs points in a manner that is beyond my spatial
> understanding.  Here is the code:
> static tf::TransformListener tf_listener;
>   //const sensor_msgs::LaserScan::ConstPtr msg_in_myframe =
> tf_listener.transformPoint(
>   // Get the transform from the laser frame to the odometry frame
>   tf::StampedTransform transform;
>   try {
>     tf_listener.lookupTransform(msg->header.frame_id, "odom",  ros::Time(),
> transform);
>
>     // Turn the laser scan into a point cloud, in the odom coordinate frame
>     sensor_msgs::PointCloud point_cloud;
>     laser_projection.transformLaserScanToPointCloud("odom", *msg,
> point_cloud, tf_listener);
>
>     for(vector<geometry_msgs::Point32>::iterator it =
> point_cloud.points.begin(); it != point_cloud.points.end(); ++it)
>       ss << it->x << ' '<< it->y << endl;
>   } catch (tf::TransformException &ex){
>     ROS_ERROR("%s", ex.what());
>   }
> --
> Todd Anderson
> (919) 710-0546
> Washington University in St. Louis Class of 2011
> School of Engineering and Applied Sciences
>
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>
>



-- 
MSc. Dejan Pangercic
PhD Student/Researcher
Computer Science IX
Technische Universität München
Telephone: +49 (89) 289-17780
E-Mail: dejan.pangercic at in.tum.de
WWW: http://ias.cs.tum.edu/people/pangercic