Caculating the distance of a point from point cloud data
I'm getting the x,y,z values for three points as follows:
x : -0.357200 y: -0.205010 z: 0.940000
x : -0.310266 y: -0.200437 z: 0.961000
x : -0.299289 y: -0.140374 z: 0.927000
and the point cloud :
Why are some of the values negative?
Does z: 0.961000 mean it is 0.961 meter away towards z axis?
Also, how is the center of these x,y,z axes computed?
The origin of the point cloud is likely near center of the sensor used to capture them- you could add detail about which sensor is being used for more help there. It could be helpful in rviz to add a Axes display that is set to the same frame as the point cloud, the colors of the axes rgb correspond to xyz. Camera and image based range sensor frames should follow the optical convention http://www.ros.org/reps/rep-0103.html... (except that they frequently neglect the
_opticalsuffix...) where +z is pointing from the sensor to the data.