Fingerprint Image Enhancement via Raised Cosine Filtering

This paper aims to present fingerprint image enhancement by using directional circular raised cosine filters which are implemented using a radial component and an angular component. It has been compared with the common filters used for bandpass filtering, i.e. circular Gabor filters and Log-Gabor filters at the same bandwidth. The experimental results have found that the circular raised cosine filters perform at par with the Gabor filters at bandwidth of three octaves for fingerprint image enhancement. The circular raised cosine filters have the advantages of: i) the frequency tail has gradual frequency response that drops towards zero, and ii) its residual can be implemented as a lowpass filter in tandem with a narrow bandpass filter. The Log-Gabor filter did not perform as well due to its design of null DC and thus the results have also shown that the DC component is necessary for fingerprint image enhancement.