Fingerprints are made up of ridge lines and intervening valleys. The points at which these lines branch or terminate are the features used in fingerprint based identification. In this image, the fingerprint itself is separated out from the rest of the image by identifying where the ridge pattern is more or less uniform over a small area of the image. The ridges are then enhanced using a process that smoothes, or blurs, the image along the direction of the ridges, but not at right angles to the ridges. Watch carefully as small breaks, false joins and zigzags are gradually removed from the ridge pattern.