Hi @TdiRex
As you know, symmetric patterns look the same when you turn them 180º. So an algorithm can come up with two solutions, and that’s why you don’t use symmetric patterns when calibrating stereo cameras.
Thus, when you use symmetric pattern on a monocular camera, findCirclesGrid uses a different algorithm, an specialized one that knows there can be two solutions, and knows which one to choose.
And that’s pretty much all of this.