Two steps for fingerprint segmentation

A fingerprint image usually consists of different regions: non-ridge regions, high quality ridge regions, and low quality ridge regions. Fingerprint segmentation is usually to exclude non-ridge regions and unrecoverable low quality ridge regions as background so as to avoid detecting false features. In ridge regions, including high quality and low quality, there are often some remaining ridges which are the afterimage of the previously scanned finger and are expected to be excluded as background. However, existing segmentation methods do not take this case into consideration, and often, the remaining ridge regions are falsely taken as foreground. This paper proposes two steps for fingerprint segmentation to exclude the remaining ridge region from the foreground. The non-ridge regions and unrecoverable low quality ridge regions are removed as background in the first step, and then the foreground produced by the first step is further analyzed so as to remove the remaining ridge region. The experimental results showed the effectiveness of the proposed method in segmenting the remaining ridges as background and in turn producing much less spurious minutiae than the existing method.