Parameter characterizing the minimal accepted quality of image corners.

The parameter value is multiplied by the best corner quality which is the minimal eigenvalue (see cv.cornerMinEigenVal) or the Harris function response (see cv.cornerHarris). The corners with the quality measure less than the product are rejected. For example, if the best corner has the quality measure = 1500, and the QualityLevel=0.01, then all the corners with the quality measure less than 15 are rejected. Default 0.01