Radtan distortion model

[Fernando Cladera]

We tracked down the problem of #5 to be the camera model, not the ROS version. This is our yaml:

cam0:
  cam_overlaps: [1]
  camera_model: pinhole
  distortion_coeffs: [-0.39654918708083786, 0.1558790317565405, -0.0010594148000153032,
    0.00025709826301464087]
  distortion_model: radtan
  intrinsics: [1073.6761539395402, 1073.8330237715743, 639.8740708893763, 350.2857551988687]
  resolution: [1280, 800]
  rostopic: /ovc/left/image_raw
cam1:
  T_cn_cnm1:
  - [0.9999989072413765, -0.00011383197661488926, 0.0014739600837072292, -0.11987932107607416]
  - [0.0001063945042586905, 0.9999872682098861, 0.0050450072678856275, 5.2472004355748504e-05]
  - [-0.0014745156007061513, -0.005044844933658041, 0.999986187576275, -0.000119575350025956]
  - [0.0, 0.0, 0.0, 1.0]
  cam_overlaps: [0]
  camera_model: pinhole
  distortion_coeffs: [-0.3966983368290133, 0.15458308333712786, -0.0009595676428343468,
    0.0005824619005361072]
  distortion_model: radtan
  intrinsics: [1070.4739652775727, 1070.8246115855497, 660.8552697003395, 357.0592968241504]
  resolution: [1280, 800]
  rostopic: /ovc/right/image_raw

Using equidistant instead of radtan works with multicam_calibration. I don't know if this is an issue, but it may be a good idea to add a note in the readme. I can submit a PR for this.

Thanks again @berndpfrommer for your help!

[Bernd Pfrommer]

I just successfully calibrated a (albeit single) camera with radtan under noetic without error. I see nothing wrong with your input file. How can I repeat this failure? It's kinda weird that it throws this error about the matrix type being wrong (cut-and-paste from #5):

Termination:                      CONVERGENCE (Function tolerance reached. |cost_change|/cost: 1.557614e-13 <= 1.000000e-12)

[ INFO] [1627162181.284741213]: writing calibration to /home/dcist/autonomy-ws/src/autonomy_stack/calibration/multicam_calibration/calib/example/./ovc-2021-07-24-17-29-41.yaml
[ERROR] [1627162181.294380799]: Exception thrown while processing service call: OpenCV(4.2.0) ../modules/core/src/matmul.dispatch.cpp:337: error: (-215:Assertion failed) type == B.type() in function 'gemm' 

As the frames arrive the calibration node writes a file "corners.csv" somewhere. Do you still have that? That should allow me to reproduce the error. Thanks!

[Bernd Pfrommer]

was bug with input arguments to stereoRectify(). The bug only bites when calibrating radtan stereo cameras.
Fixed.

[erinline]

What was the input argument error, and how did you fix? I'm getting the same error with stereoRectify, and my distortion model is plumb_bob, not radtan

[erinline]

NVM, fixed it myself. In my case, the issue was I had initialized the translation vector as Vec3f in input to stereoCalibrate, but stereoRectify required Vec3d