Matched filter design for fingerprint image enhancement

A procedure for filter design is described for enhancing fingerprint images. Four steps of this procedure are described: user specification of appropriate image features, determination of local ridge orientations throughout the image, smoothing of this orientation image, and pixel-by-pixel image enhancement by application of oriented, matched filter masks. The contribution of this work is to quantify and justify the functional relationships between image features and filter parameters so that the design process can be easily modified for different conditions of noise and scale. Application of the filter shows good ridge separation, continuity, and background noise reduction