Contactless Fingerprint Image Enhancement Algorithm Based on Hessian Matrix and STFT

In order to enhance the contrast between ridges and valleys of contactless fingerprint, a touchless fingerprint image enhancement algorithm based on Hessian matrix and short time Fourier transform (STFT) analysis is proposed. First, initial enhancement is done through building lower computational complexity Hessian matrix filter, on the basis of the feature that the ridges of contactless fingerprint are linear structure and relatively brighter. Then, the method of STFT analysis is used to enhance the contactless fingerprint image once more according to the texture characteristics of fingerprint, which also can effectively restrain the noise. Experimental results show that the proposed algorithm can not only significantly enhance the contrast of contactless fingerprint image, but also is faster.