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Advances in Fingerprint Technology.pdf

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(a) (b)<br />

(c)<br />

Figure 8.3 F<strong>in</strong>gerpr<strong>in</strong>t compression: (a) an uncompressed f<strong>in</strong>gerpr<strong>in</strong>t image; (b)<br />

portion of image <strong>in</strong> (a) compressed us<strong>in</strong>g a generic image compression algorithm,<br />

JPEG 13 ; and (c) portion of image <strong>in</strong> (a) compressed us<strong>in</strong>g Wavelet/Scalar Quantization<br />

(WSQ), a compression algorithm specifically developed for compress<strong>in</strong>g<br />

images. Both JPEG and WSQ use a compression ratio of 12.9; JPEG typically<br />

<strong>in</strong>troduces blocky artifacts and obliterates detailed <strong>in</strong>formation. See Reference<br />

14 for more detailed imagery.<br />

identification system, it is both <strong>in</strong>feasible and socially unacceptable to use the<br />

rolled <strong>in</strong>ked method to acquire f<strong>in</strong>gerpr<strong>in</strong>ts <strong>in</strong> the operational phase, although<br />

it may be feasible to use the rolled <strong>in</strong>ked method <strong>in</strong> the enrollment phase.*<br />

Another method of acquir<strong>in</strong>g an <strong>in</strong>ked impression is called a dab (see<br />

Figure 8.4b). In this method, the <strong>in</strong>ked f<strong>in</strong>ger is simply impressed on the paper<br />

without roll<strong>in</strong>g it from nail to nail. Obviously, the f<strong>in</strong>gerpr<strong>in</strong>t dab images cover<br />

a smaller f<strong>in</strong>gerpr<strong>in</strong>t pattern area, but there is a smaller distortion <strong>in</strong> the pr<strong>in</strong>t.<br />

* For example, Master Card relies on <strong>in</strong>ked impressions for enrollment.

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