Obtaining and processing fingerprint data, fingerprint can be broken down into two basic features. By examining these characteristics, it is possible to extract data from raw fingerprints and store it in a computer database for future comparisons. Images can be captured using one of several devices, including:

Optical Scanners 
Thermal Scanners 
Capacitive (Solid-State) Scanners 

Biometrics consists of automated methods of recognizing a person based on unique physical characteristic. Each type of biometric system, while different in application, contains at least one similarity: The biometric must be based upon a distinguishable human attribute such as a person's fingerprint, iris, voice pattern or even facial pattern.
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A fingerprint is made up of a pattern of ridges and furrows as well as characteristics that occur at Minutiae points (ridge bifurcation or a ridge ending). [See Diagram Below]. Fingerprint scanning essentially provides an identification of a person based on the acquisition and recognition of those unique patterns and ridges in a fingerprint.
 
Fingerprint Scanners Work

(How Fingerprt Scanners Work)
Extract Data after Capture, there are currently two accepted methods for extracting this data: minutia-based and correlation-based. Minutia-based 英语论文网 【http://www.51lunwen.org】is the more microscopic of the two, locating ridge branches and endings and assigning them an XY-coordinate that is then stored in a file. Correlation-based looks into the overall pattern of ridges and valleys. Instead of looking for tiny minutia points, the locations of whorls, loops and arches and the directions that they flow in are extracted and stored.

Neither method actually keeps the captured image; only the data is kept, therefore making it impossible to recreate the fingerprint. Both methods have their drawbacks, though. Minutia-based comparison requires that the fingerprint image be high quality, with dirt, water, scars and cuts having a significant impact on proper identification. On the other hand, correlation-based comparisons can be affected by image translation and rotation.
 
Size of the fingerprint data template, fingerprint requires one of the largest data templates in the biometric field. The finger data template size can range anywhere from several hundred bytes to over 1,000 bytes depending upon the level of security that is required and the method that is used to scan one's fingerprint. The good news is that there are algorithms being developed that can "enhance" images in order to reduce distortion and false data while minimizing file size.
 
After the initial setup of an authorized user, every time he or she wants to access the system, the fingerprint is run through the same algorithms used when it was stored. This data 本文来自：英语论文网 【http://www.51lunwen.org】