Robust Fingerprint Image Enhancement: An Improvement to Directional Analysis of Fingerprint Image Using Directional Gaussian Filtering and Non-subsampled Contourlet Transform

In this paper, a new fingerprint image enhancement method based on the integration of directional Gaussian filtering and non-subsampled contourlet transform (NSCT) has been proposed. As the fingerprint images suffers from non-uniform illumination, so there is a need to completely remove or reduce the non-uniform illumination present in the fingerprint image before applying any enhancement technique. In this paper, we have used bandpass filter for the elimination of non-uniform illumination and for the creation of frequency ridge image. Further the directional noise present in the fingerprint image have been removed by using the directional Gaussian filter and the noise-free image was decomposed into non-subsampled directional images by using NSCT. Lately, we construct an enhanced image through a block-by-block process which compares the energy of all the directional images and picks the one that provides maximum energy. Further, binarization and thinning are also applied on the enhanced image.