On the design of 2-D Gabor filtering of fingerprint images

The directional bandpass Gabor filter-bank approach is one of the most effective and mathematically elegant techniques to date for fingerprint image enhancement. The filter output, however, is very sensitive to the ridge orientation and frequency that the filter is tuned to, and also to the spatial parameters of the Gaussian envelope. Unfortunately, filtering of a fingerprint image with an adaptive 2-D Gabor filter bank is computationally expensive because ridge orientation and frequency vary significantly throughout the fingerprint. In this paper we propose to use an array of 8 x 1 two-dimensional Gabor fibers tuned to eight directions and four ridge frequencies. Filtered fingerprint images at any combination of local ridge orientation and frequency can be calculated using a 2-D interpolation algorithm The proposed technique produces a better quality of image than current Gabor-based techniques. The results are compared using a goodness index measure of the reliability of the automatic minutiae detection.