terminate called after throwing an instance of 'cv::Exception' what(): OpenCV(4.2.0) ../modules/calib3d/src/calibration.cpp:3681: error: (-215:Assertion failed) nimages > 0 in function 'calibrateCameraRO'

[mahadyRayhan]

System information (version(

• Operating System / Platform => jetson AGX orin Ubuntu 20.04.5
• OpenCV => 4.7.0.72
• Boost => 1.71.0
• Compiler => 9.4.0

Describe the issue / bug

I want to use this repo for camera calibration. As a test I run it using your images (Blender_Images/Scenario_4). I use this config file "configs/Blender_Images/calib_param_synth_Scenario4.yml"

but I got this error. 0000762 | 2023-03-10, 02:24:33.156627 [info] - NB of board available in this camera :: 67 0000763 | 2023-03-10, 02:24:33.156632 [info] - NB of frames where this camera saw a board :: 0 0000764 | 2023-03-10, 02:24:44.361150 [info] - cameraMatrix : [1635.287632190865, 0, 910.472362025855; 0, 2180.326265734438, 687.7097065417272; 0, 0, 1] 0000765 | 2023-03-10, 02:24:44.361268 [info] - distCoeffs : [0.0001881855340537709, 0.0001065567381201567, 7.716848715255847e-06, -0.0001258552711169724, -0.001051052282729498] 0000767 | 2023-03-10, 02:24:44.361315 [info] - NB of board available in this camera :: 141 0000768 | 2023-03-10, 02:24:44.361320 [info] - NB of frames where this camera saw a board :: 0 0000769 | 2023-03-10, 02:24:53.939454 [info] - cameraMatrix : [1578.668569187077, 0, 911.4712304244889; 0, 2104.935810986766, 687.5970880791547; 0, 0, 1] 0000770 | 2023-03-10, 02:24:53.939569 [info] - distCoeffs : [6.609636345427984e-05, -0.0006555977869654838, 8.510591129891801e-06, -5.470965711278653e-06, 0.001270262034885951] 0000772 | 2023-03-10, 02:24:53.939625 [info] - NB of board available in this camera :: 0 0000773 | 2023-03-10, 02:24:53.939632 [info] - NB of frames where this camera saw a board :: 0 terminate called after throwing an instance of 'cv::Exception' what(): OpenCV(4.2.0) ../modules/calib3d/src/calibration.cpp:3681: error: (-215:Assertion failed) nimages > 0 in function 'calibrateCameraRO'

Aborted (core dumped)

As you can see,

NB of board available in this camera :: 141 NB of frames where this camera saw a board :: 0

NB of board available in this camera :: 0 NB of frames where this camera saw a board :: 0

could you support me ?

[rameau-fr]

Hello,

It seems that the third camera did not capture any images where a checkerboard had been detected. Therefore, the intrinsic calibration of the camera cannot be performed, and the function returns an error.

It can be due to multiple reasons:

• No boards appear at all in this camera (in this case, the camera cannot be calibrated at all)
• A problem with folder naming (make sure you follow the proper naming convention)
• A problem with the checkerboard generation/detection

The third issue is by far the most probable. I would have a few questions to help you:

1. May you please share your configuration file
2. How have you generated your checkerboards?

If you could share your images with me, I can also check them in more detail. If you do not want to share your entire calibration data, at least one picture from each camera looking at a checkerboard would help too.

Thank you very much for using MC-Calib!

[mahadyRayhan]

Hi,

thank you for your response. I am using your Blender generated images as a test approach.

• I check the images, and there are images with boards
• folder names are as expected (Cam_001 Cam_002 Cam_003 Cam_004)

regarding detection issue:

• As I said I am using your Blender generated images as a test images (after test is successful, I will use my own images). I used your this (configs/Blender_Images/calib_param_synth_Scenario4.yml) config file unchanged.
• to generate checkerboard, i use this command as you mentioned (./generate_charuco ../configs/configs/Blender_Images/calib_param_synth_Scenario4.yml)

[rameau-fr]

Thank you for your response! Sorry I missed the part of your original message where you mentioned the data you were using. I will try on my computer first to see if I can replicate this error. Between our initial tests and the current version, we might have modified the way we generate the checkerboards, it might be related to that. For now, I have no access to my desktop computer, but I will try to keep you updated as soon as I can. Thank you again!

[mahadyRayhan]

did you get time to check the issue?

[rameau-fr]

We have just tried the sequence you mentioned. It is working well on our side. I am unsure what problem you are facing exactly; it might be a problem with the path in the configuration file that you might need to adjust on your system. It could also potentially be a problem with versioning, have you tried using docker by any chance?