Local features is refers to the fingerprint of nodes on the biometric fingerprint time clock characteristics, these have some characteristics of the node called feature points. Two fingerprint often have the same general characteristics, but their local characteristics - feature points, but could not completely the same. Fingerprint grain is not continuous, smooth straight, but often interrupt, points and or discount. The breakpoint, bifurcation point and turning point is called "feature point". "Feature point" can be subdivided into endpoint, points and point, bifurcation, isolated point, ring point and short grain etc., one of the most typical is the endpoint and bifurcation point. It is these characteristics point provides fingerprint only - sex confirmation.

Automatic time and attendance systems technology is from science fiction and Hollywood movie into our real life, maybe one day, you don't have to carry that a bunch of keys, just a click of the fingers, the door will open; Also don't have to remember that annoying password, using fingerprint can drawings, computer login. Believe this one day, not too far away.

point 1. The biometric time clock is the unique features of the human body, and complexity to provide is used to identify characteristics. 2. Scanning fingerprints very fast, easy to use. 3. Read fingerprints, users must will fingers and fingerprint acquisition head direct contact, enhance recognition reliability. (4) fingerprint acquisition head can be more miniaturization. shortcomings 1. Some groups of fingerprint features are very few, difficult to imaging. 2. Collection head left the user's fingerprint trace, has been one copy, the possibility of using.
Optical take like fingerprint time clock equipment has the long history, can be traced back to the 1970 s. Optical take like equipment based on the light's total reflection principle (FTIR). The light to pressure have fingerprint glass surface, reflex the light by CCD to get, and the amount of reflected light depends on the pressure in the glass surface fingerprint ridge and depth and skin and glass between oil and water. Light through glass shot to the valley after the place in the glass and air interface happen total reflection, the light is reflected to the CCD, and into ridge light does not occur total reflection, but by ridge and glass contact surface absorption or diffuse to other places, so in the CCD is formed on the fingerprint image.



Each person's fingerprints skin texture in the design and fingerprint time clock delivery, breakpoint righteousness point each are not identical, is the only, and lifetime is changeless, rely on the uniqueness and stability, you can take - individual with his fingerprint corresponding up, through his fingerprints and preserved fingerprint comparison, can verify his true identity, this is the fingerprint recognition technology. principle Fingerprint is actually more complex. And artificial processing different, many biological recognition technology companies do not direct memory fingerprint image. For many years in the companies and research institutions have many digital algorithm (the United States relevant laws that fingerprint image belong to personal privacy, therefore cannot directly processing fingerprint image). But the fingerprint identification algorithm finally boil down to find and in fingerprint image than the characteristics of fingerprint.