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Transform realtive to absolute position

Hello everyone,

i am looking for a way to transform a tf message to the absolute position.

My project: I have 5 cams wich should observe a certain area in wich i detect ar tags using ar_track_alvar. I set up 3 cams so far. Theire fields of view overlap to make enable sensor fusion. I am working with python usung ros indigo on a ubuntu 14.04

My Problem: I am listening to the tf tree updates to get to know where the markers are detected but the tf tree only gives me the relative position to the camera which is detecting the marker at the moment. I can't use lookupTransform because i wont be able to tell which camera gave me that transform (there are switching back and forth quickly). This is important for me because i am gathering data for the sensor fusion. I know there is a method in cpp to do just what i need but i am not yet willing to rewrite my whole code to cpp only for that function. Is there a quick way to solve my problem in python or do i need to code it myself? If i need to code it myself i would be thankfull for a quick description how this is done since i am not that fit in linear algebra.

I hope you get my question and i have not overseen an easy way to solve this

RichardS

Transform realtive to absolute position

Hello everyone,

i am looking for a way to transform a tf message to the absolute position.

My project: I have 5 cams wich should observe a certain area in wich i detect ar tags using ar_track_alvar. I set up 3 cams so far. Theire fields of view overlap to make enable sensor fusion. I am working with python usung ros indigo on a ubuntu 14.04

My Problem: I am listening to the tf tree updates to get to know where the markers are detected but the tf tree only gives me the relative position to the camera which is detecting the marker at the moment. I can't use lookupTransform because i wont be able to tell which camera gave me that transform (there are switching back and forth quickly). This is important for me because i am gathering data for the sensor fusion. I know there is a method in cpp to do just what i need but i am not yet willing to rewrite my whole code to cpp only for that function. Is there a quick way to solve my problem in python or do i need to code it myself? If i need to code it myself i would be thankfull for a quick description how this is done since i am not that fit in linear algebra.

I hope you get my question and i have not overseen an easy way to solve this

RichardS