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Ground truth

The ground truth was captured via a GoPro, by tracking an ArUco marker's pose (Original ArUco, id=1, 100mm).

slammy_ground_truth_two_loops.gif
Video: assets/slammy_ground_truth_two_loops.avi

Calibrated images

The calibrated images can be dowloaded from: https://webdav.ifp.uni-stuttgart.de/s/aswTjBa3JtDrffM (810Mb).

slammy_cam_calibartion_workflow

Calibration workflow:
Raw -> Linear (via fis eye calibration)
Following this: https://www.mathworks.com/help/vision/ug/fisheye-calibration-basics.html Linear -> Rectangular (via homography and known ground points).
As explaine here: https://docs.opencv.org/4.5.2/d9/dab/tutorial_homography.html

AruCo target tracking

Use openCV to track an AruCo marker:

https://docs.opencv.org/3.4/d5/dae/tutorial_aruco_detection.html

The marker was roughly located by hand. The exact pixel coordinates and the orientation was then determined in openCV.

Transformation from pixel to world

The transformation of pixel coordinate x = [x_pix y_pix] to a world coordinate X = [x_world y_world] can be done by: X=R*x+t with:

R =
  -1.1096e-06    -0.001002
  -0.00099834  -4.9957e-06

and

t =
       5.0288       7.4108

Note: Due to the homography, this transformation is only valid for objects with Z=0.4m. This is equal to height of the ArUco marker in all images.

Path

The file slammy_ground_truth_two_loops.txt contains the path world and pixel coordinates, along with the estimated pose and the image.

X[m],Y[m],Heading [deg],Time,piX,piY,Path_to_Image
0.005,-0.003,7.2,16-Jul-2021 15:30:51,7402,5006,G0019266_linear_linear_rectangle.jpg
0.004,-0.003,5.9,16-Jul-2021 15:30:51,7401,5006,G0019267_linear_linear_rectangle.jpg
0.005,-0.003,7.2,16-Jul-2021 15:30:52,7402,5006,G0019268_linear_linear_rectangle.jpg
0.005,-0.003,6.5,16-Jul-2021 15:30:52,7401,5006,G0019269_linear_linear_rectangle.jpg
0.004,-0.004,6.6,16-Jul-2021 15:30:53,7402,5006,G0019270_linear_linear_rectangle.jpg
0.005,-0.003,7.7,16-Jul-2021 15:30:54,7402,5006,G0019271_linear_linear_rectangle.jpg
0.004,-0.003,6.6,16-Jul-2021 15:30:54,7402,5006,G0019272_linear_linear_rectangle.jpg
0.005,-0.003,7.8,16-Jul-2021 15:30:54,7401,5006,G0019273_linear_linear_rectangle.jpg
...

Coordinate System

The coordinate system is defined as follows:
slammy_office_crs

Note: Due to the homography, this transformation is only valid for objects with Z=0.4m. This is equal to height of the ArUco marker in all images.