Quad refinements are randomly selected

[qbonnard]

If multiple quads are found to contain a tag, the latest detected is chosen. This may explain why the corners are sometimes "shaking".
There should be a better way to pick the best quad for a detected tag.

[severin-lemaignan]

What about keeping the one with the smallest perimeter? this should be the one the closest to the actual marker.

[qbonnard]

Sounded good, but it doesn't work perfectly. Now it flickers towards the inside. Do you want me to share my branch ?

[severin-lemaignan]

One option that could help mitigate: use thresholding instead of Canny:

l.90 of FindQuads:

cv::threshold(mGrayPyramid[i], mBinaryPyramid[i], -1, 1, cv::THRESH_BINARY | cv::THRESH_OTSU);