Estimation of the directional field anisotropy based on Mohr's Circle in fingerprint images

Traditional gradient based methods are used for the estimation of directional field anisotropy and the associated values called coherence/strength that denote the consistency of the orientation. Using a geometric interpretation of Mohr's Circle, a new method is proposed to estimate the directional field anisotropy and a new indicator called uniformity is introduced. Starting from the autocovariance 2×2 symmetric matrix, eigenvalues are computed and yield the new measure for anisotropy.