FEATURE EXTRACTING DEVICE FOR FINGERPRINT IMAGE

摘要

PURPOSE:To realize the quick extraction of features of a fingerprint image by obtaining the feature points based on an extremely small number of image elements (image elements set along a contour) only out of an entire fingerprint image. CONSTITUTION:The image elements set along a contour of a fingerprint image are extracted by a contour extracting means 1. Then an image element extracting means 2 extracts a series of those extracted image elements every fixed numbers, e.g., three image elements. A directional difference calculation means 3 connects two adjacent image elements to each other to obtain a directional vector out of those image elements extracted every fixed number of image elements. Then the angle difference between two adjacent directional vectors is calculated and compared with a prescribed threshold value by a comparison means 4. Parts larger than said threshold value are regarded as feature point candidates and outputted. Thus only the image elements set along a contour of an entire fingerprint image extracted and the feature points of a fingerprint image are obtained based on said image elements. Then the features of the fingerprint image can be quickly extracted.