Verification of Xtion calibration

Preparing

It's needed to choose locations on the robot, where position of marker has to be measured accurate enough (for example on the gripper), otherwise error of verification will be bigger than error of calibration.

  • Marker description: /clopema_testbed/clopema_description/urdf/alvar_marker.urdf.xacro
  • This xacro is loaded in: clopema_description/robots/clopema_PARTNER.urdf.xacro (origin is target center)

Verification

  • In clopema_testbed/clopema_calibration/verification_xtion_alvar, there is node verification_xtion_alvar.cpp

rosrun clopema_calibration -r 1 - only r1
rosrun clopema_calibration -r 2 - only r2
rosrun clopema_calibration - both r1 and r2

  • This node loads file verification_markers_list.yml, which has to be located in package clopema_testbed/clopema_calibration/verification_xtion_alvar/src/ folder.
  • In this file is list with definition of alvar markers used for verification and with defined positions of xtion with respect to these markers. All of used marker you must have in robot xacro, of course.
  • After node is done, some output files are saved in clopema_testbed/clopema_calibration/verification_xtion_alvar/output.
  • These files can be than evaulated in m-file clopema_testbed/clopema_calibration/verification_xtion_alvar/src/verify_xtion_alvar.m

1. Residual errors of marker position calculated as intersecion of xtion rays to marker in robot coordinates (all markers together)

2. Residual errors of marker position calculated as intersecion of xtion rays to marker recomputed to xtion image coordinates (for each marker)

verification_robot.png (9.17 KB) Karel Krehnac, 05/06/2014 14:07

verification_xtion_image.png (6.13 KB) Karel Krehnac, 05/06/2014 14:07