camera-calibration-supervisor

August 2, 2021 · View on GitHub

This README is a guide to use the camera-calibration-supervisor for the ATIS cameras mounted on iCub. If you need more information just have a look to the original repo!

The stereo calibration or the mono calibration allows obtaining intrinsic and extrinsic parameters removing distortions from the lenses. The camera-calibration-supervisor is a user-friendly framework that identifies the best chessboard poses guiding you into the next chessboard position. This set of positions are the best set to obtain a good calibration.

How to set up your calibration on the robot 🤖

Requirements

  • Laptop with the installed camera-calibration-supervisor app: icub23
  • Checkerboard-fast: SAMSUNG tablet
  • iCub's eyes vergence ~ 5

Let's start with the calibration on the robot!

  • First of all you need to turn on the iCub's motors and CPU by clicking the buttons on the side of the iCub's backpack. Then, run yarpmanager and run icub-head,icub-zynq & icub-23/24from the Cluster.

  • From Entities search foriCubStartup-eventdriven application and run:

    • yarplogger to check any error occurring using the robot.
    • yarprobotinterface to run the robot.
    • Do not forget to shift iCub's eyes vergence to ~ 5 (yarpmotorgui from the terminal, /head, JOINT5)

  • From Entities search for vViewCamCalibSupervisor application, run and connect everything.

  • From Entities search for Event_Cam_Calib_Supervisor_App application and run all the yarpviews.

    • Then, from a terminal run stereoCalib --from icubEyes_ATIS-board-gazebo.ini.
    • Finally, run calibSupervisor from the Event_Cam_Calib_Supervisor_App application and connect everything.

Please, make sure to check the .ini file. It should look like the one below:

[CAMERA_CALIBRATION_RIGHT]

projection         pinhole
drawCenterCross    0

w 304
h 240
fx 195.625
fy 195.719
cx 141.748
cy 131.03
k1 -0.341102
k2 0.0972876
p1 -0.00761546
p2 0.00759488

[CAMERA_CALIBRATION_LEFT]

projection         pinhole
drawCenterCross    0

w 304
h 240
fx 179.823
fy 178.975
cx 157.431
cy 114.611
k1 -0.304171
k2 0.193928
p1 -0.000112923
p2 -0.0111818

[STEREO_DISPARITY]
HN (0.999425 0.00522887 -0.0335127 0.096062 -0.00676219 0.998928 -0.0458046 -0.0046386 0.0332373 0.0460048 0.998388 0.0465875 0 0 0 1)
QL (-0.000767	-0.000192	-0.026078	 0.003068	-0.003068	-0.001534	-0.000479	 0.043191)
QR (-0.000767	-0.000192	-0.026078	 0.003068	-0.003068	-0.001534	-0.000479	-0.043191)

[STEREO_CALIBRATION_CONFIGURATION]
boardWidth 8
boardHeight 6
boardSize 0.021675
numberOfPairs 30
  • Open a yarp rpc port: yarp rpc /stereoCalib/cmd and type start. You should get something like this:
>>start
Response: "Starting Calibration..."

This step should be handled by stereoCalib, but if you want to monitor the ongoing process I advise you to run stereoCalib from a terminal looking at what the application returns.

  • Now, your calibration is ready to start. Therefore, take your chessboard and put the yarpviews (/display, /viewleft and /viewright) visible whilst you are moving your board. The calibration process needs to collect several good positions for the board that is equal to the numberOfPairs of the .ini file. Please, be sure stereoCalib is collecting the images writing: [INFO] Saving images number #

  • Once you have collected all the positions is the time to obtain the intrinsic and extrinsic parameters running the script:

modify-params.sh icubEyes_ATIS-board-gazebo.ini outputCalib.ini cameraCalibration

This script will overwrite the results on the initial .ini file. You should obtain something like this:

Using file /home/icub/.local/share/yarp/robots/iCubGenova02/icubEyes_ATIS-board-gazebo.ini
stereoCalib writes the following file: /home/icub/.local/share/yarp/contexts/cameraCalibration/outputCalib.ini
 
Running script...with params /home/icub/.local/share/yarp/robots/iCubGenova02/icubEyes_ATIS-board-gazebo.ini /home/icub/.local/share/yarp/contexts/cameraCalibration/outputCalib.ini cameraCalibration
 
 
Script completed successfully...
  • Let's now check our calibration! Run Event_Calib_Cameras and conenct everything. You now should be able to see the chessboard with no distortion!