Why is the number of rows and columns of april grid are limited to a minimum of 3

[Ruthrash]

kalibr/aslam_offline_calibration/kalibr/python/kalibr_common/ConfigReader.py

Line 613 in f581b27

if not isinstance(tagRows,int) or tagRows < 3:

Any prinicipled reason for limitied minimum number of rows and columns to 3?

[goldbattle]

I believe this is because it is detecting the inner corners of the checkerboard, which is not possible with less than 3 rows or columns. Maybe you could search about OpenCV's checkerboard detection to understand more.

[Ruthrash]

I understand that's the case for the checkerboard, but my question was for the april grid. I can think of no reason why we need to limit it for the april grid case

[goldbattle]

Very true, would need to test to see if that gives good results.