time and attendance systems background knowledge Our palms and fingers, feet, toes medial surface skin rough and uneven produce lines will form all kinds of design. The existence of these grain increased at the surface of the skin friction, so that we can use hand to grab the weight. People also pay attention to, including fingerprint, the skin texture in the pattern, breakpoint and crossing each are not identical, that is to say, is the only. Rely on this uniqueness, we can put a man with his fingerprint corresponding up, through to his fingerprints and preserved fingerprint comparison, it can be used to verify his true identity. This depend on human body characteristic to carry out identity verification technology, called biological recognition technology, fingerprint recognition is a kind of biological recognition technology.
At present, from a practical point of view, time and attendance systems is superior to others biological recognition technology identification method. This is because the fingerprint each are not identical, lifelong fundamental characteristics have been recognized. The earliest fingerprint recognition system application and the police criminal suspects detection, there have been more than 30 years of history, the fingerprint identification of research and practice have laid a good technical basis. Especially now fingerprint identification system has reached the operation is convenient, accurate and reliable, price moderate stage, is gradually applied in civil market.
time and attendance systems is refers to the human finger appear on strip lines. Their formation depends on the environment during embryonic development. “No two identical fingerprint” this view has been accepted. Fingerprint recognition has a long history of time. At present, fingerprint identification has been accepted by the official in the legal profession to become a kind of effective identity identification method. The global scope have established the fingerprint identification institutions and criminals fingerprint database. As the most traditional, the most mature biological appraisal way, fingerprint as follows two prominent advantages:
1) stability: fingerprint time clock has a strong relative stability. From fetal six months fingerprint fully formed bodies to decay, fingerprint ridge type, structure, statistical characteristics of the population distribution and always did not change significantly. Although with the increase of age, fingerprint in appearance size, grain line weight will produce some change, local grain online may also appear new features. However, from the overall perspective, fingerprint is relatively stable: even if the finger skin injury, as long as it doesn’t hurt and the dermis, after his grain line can still restore; If the injury and genuine leather, formed from the scar although damaged grain line, but the scar itself is the formation of a new stability characteristics.
Local features: time and attendance systems endpoint and bifurcation point is the most commonly used fingerprint local structure characteristics, also known as the detail characteristics. Use this feature a example is details – coordinate model, that is, using fingerprint minutiae and coordinates and other features to describe the fingerprint. For fingerprint identity identification, especially the fuzzy fingerprint recognition on when the use of information is detail feature point, as shown in figure 3 shows the bridge, ring, branch point, triangulation point and end. People according to the grain of local structure characteristics were defined about more than 150 kinds of details characteristics, if at the same time use all of these characteristics, it would be very difficult to automatic and quickly from fingerprint image extraction and distinguish between them. Usually, the automatic fingerprint identification system using only two main characteristics, namely bifurcation point and end. Other details characteristics can use their combination said. For example, small bridge is made up of two end of composition, and ring is made up of two branch point of composition.