Directional edge enhancement using superposed vortex filter

• We propose new vortex based filter for directional edge enhancement.
• The mathematical analysis for the Fourier transform of the filter and explanation for the filer characteristics are presented.
• The filter application is experimentally demonstrated.
• The application of proposed filter in fingerprint contrast enhancement is shown.

A new filter with azimuthal amplitude variation for directional edge enhancement is demonstrated. The filter can be seen as a superposition of two radial Hilbert filters of opposite topology. Directional edge enhancement property is explained by studying the filter and its transfer functions. Experimental and simulation results are presented and the advantages of this filter in fingerprint contrast enhancement are shown.