| 摘要 |
The detection of fingerprint feature is performed on the basis of a directional distribution of fingerprint obtained by setting a plurality of points on a circle having a center corresponding to a mark point on a directional pattern of ridges, obtaining inner products of vectors indicating tangent lines and vectors indicating ridges at the respective points and providing a distribution of the inner products as a directional distribution of ridges, in the following manner. That is, as the first method, Fourier expansion means Fourier-expands the directional distribution of ridges and outputs Fourier coefficient every frequency component, power calculation means calculates power of every frequency component on the basis of the Fourier coefficients and power determination means detects the fingerprint feature on the basis of the power of every frequency components. As a second method, smoothing means divides the directional distribution of ridges into a plurality of paraiel distributions and smooths the respective partial distributions and zero cross detection means detects the number of changes of value of the plurality of the smoothed partial distributions from positive to negative or negative to positive as the number of zero crossings and detects the fingerprint feature on the basis of the number of zero crossings. <IMAGE> |
