No corners could be extracted

[1zgh]

I've taken a lot of photos, why do I keep having this problem? Can anyone help me see it, here's my error and photos. Thank you so much！！

importing libraries
Initializing cam0:
Camera model: pinhole-radtan
Dataset: /data/20240423/vis_ir_nir.bag
Topic: /cam0/image_raw
Number of images: 43
Extracting calibration target corners
Progress 43 / 43 Time remaining: 59m 60s
[FATAL] [1713867776.590952]: No corners could be extracted for camera /cam0/image_raw! Check the calibration target configuration and dataset.
Traceback (most recent call last):
File "/catkin_ws/src/kalibr/aslam_offline_calibration/kalibr/python/kalibr_calibrate_cameras", line 465, in
main()
File "/catkin_ws/src/kalibr/aslam_offline_calibration/kalibr/python/kalibr_calibrate_cameras", line 188, in main
if not cam.initGeometryFromObservations(observations):
File "/catkin_ws/src/kalibr/aslam_offline_calibration/kalibr/python/kalibr_camera_calibration/CameraCalibrator.py", line 57, in initGeometryFromObservations
success = self.geometry.initializeIntrinsics(observations)
RuntimeError: [Exception] /catkin_ws/src/kalibr/aslam_cv/aslam_cameras/include/aslam/cameras/implementation/PinholeProjection.hpp:716: initializeIntrinsics() assert(observations.size() != 0) failed: Need min. one observation

[AntonioLuisGlez]

Hello! Did you checked yout target table .yaml? In this file you have to specify the number of rows and columns as well as the square size.

[katafoxi]

I had the same error. It turned out that rows and columns are something completely different. Therefore, I specified incorrect data in the configuration grid.yaml file.
You need to correctly count rows and columns like this.

[WFram]

Regarding AprilGrids, sometimes the problem lies not in incorrect configuration written in .yaml, but in wrong ID assignment issues. Here assumed that IDs are starting with 0:

kalibr/aslam_cv/aslam_cameras_april/src/GridCalibrationTargetAprilgrid.cpp

Line 132 in 1f60227

if (iter->id >= (int) size() / 4)

As a hotfix, you can find out the start ID and subtract it from all the IDs. For my case I was able to obtain proper calibration with this fix.