A New Method for Improving Robustness of Registered Fingerprint Data Using the Fractional Fourier Transform

Inspired by related studies, a new data processing method in fingerprint authentication using the fractional Fourier transform (FRT) was proposed for registered fingerprint data. In this proposal, protection of personal information was also taken into account. We applied the FRT instead of the conventional Fourier transform (FT) which has been used as one of the representative fingerprint authentication algorithm. Our method solved the problem of current registration method and the robustness was verified. In this study, a modeled fingerprint image instead of the original raw fingerprint images was analyzed in detail to make the characteristic clear. As one dimensional (1D) modeled fingerprint image, we used the finite rectangular wave which is regarded as the simplification of the grayscale distribution in an arbitrary scanned line of the raw fingerprint images. As a result, it was clarified that the data processed by the FRT provide higher safety than those processed by the FT, because it is difficult to specify the orders from the intensity distribution of FRTs (the intensity FRTs) when the combination of the various FRTʹs order at every scanned line is used.