Application of the recognition technology of fingerprint
To use history to be long fingerprint, can trace back to several thousand year, begin, apply administration of justice to practise in a manner to put one’s fingerprint ancient times and among the commercial trade. With the development of computer technology, the recognition technology of fingerprint has grown from past artificial discernment to automatic fingerprint recognition too. As biological for one kind of the characteristic recognition technology ones,last uniqueness and characteristics of stability, so we, through the identity that we can be only of confirming a person of fingerprint. Discern the method as to the traditional identity, fingerprint recognition does not have the problem that lost and forgotten, have already become the grinding and generating heat to click of the market. The recognition technology of automatic fingerprint is one of the biological characteristic recognition technology used most extensively at present, according to investigating statistics of the company, the market share of the recognition technology of fingerprint has accounted for above 60 that the whole biological characteristic discerns the market. And the reducing with the cost of goods of recognition technology of automatic fingerprint, the range of application of the fingerprint products and capacity of the market are larger and larger, and present annual market growth rate is all above 30%, attract numerous investors.
One of the key technology of the fingerprint products is the fingerprint transducer. The main one at present of fingerprint transducer is divided into three kinds. Optical transducer, the transducer of the semiconductor, ultrasonic transducer.
The optical transducer is the most traditional fingerprint transducer, reflect the fingerprint picture on the photoelectric device through a piece of prism, get the picture through sampling. The characteristic of the optical transducer is that a formation of image is effectual, the shortcoming is relatively bad to the dry formation of image of fingerprint, it was epidermis fingerprint that was gathered, not able to bear spots, and more difficult miniaturization.
The transducer of the semiconductor is divided for the electric capacity type again according to measuring the difference of principles, the inductance type, temperature sensing type three big classes. Three picture that technology gather these has his strong points, advantage with low costs generally speaking, small, the shortcoming is that the quality of the transducer formation of image is worse than the optical one, and antielectrostatic, it is bad to resist the destructiveness, the life-span is relatively short too. Divided into two big classes, pressing type and slipping type again according to user’s occupation mode.
Principle that ultrasonic transducer exceed to based on skin, reflect to whom supersonic wave produce with impedance measure fingerprint with air the fingerprint. This kind of technology had the characteristics that the formation of image is clear, it was genuine leather fingerprint that was gathered, the ability to resist spot is strong. But its shortcoming is that the price is very expensive, it is unable to be used on a large scale all the time.
The technology of the transducer has been already ripe day by day at present, towards higher quality of formation of image in the future, smaller volume of using, the more low-cost direction is developed. Among them develop fastest with the fingerprint transducer of the semiconductor, need bigger silicon to accumulate one-sidedly because of adopting and pressing the way semiconductor transducer of formation of image, so the space that the cost in the future reduces is limited. We think and mainly concentrate transducer development in future on the slipping type fingerprint transducer of the semiconductor, the products with typical in this respect have AES2501 series of Authentec Company,etc.. And the volume of the transducer that the main developing direction of optical transducer should dwindle mainly, improve the quality of the formation of image. The typical products have U.are.U 4000 series of DigitalPerson Company of U.S.A.,etc..
According to characteristic of the transducer, the transducer of the semiconductor is relatively suitable for pressing less number of times, the occasion with better environment for use such as information safety of the computer, hand-held device (PDA, cellular telephone) ,The fingerprint U plate, fingerprint keyboard, the fingerprint mouse,etc.. The optical transducer is relatively suitable for fingerprint to lock, the entrance guard, attendance,etc. employ the occasion. Especially make fingerprint locked, what basically use is all the products of the optical transducer at present.
The fingerprint recognition algorithm is another key technology of the fingerprint products. The fingerprint recognition algorithm through using on PC at present has been already riper, but the algorithm used in various embedded systems has larger development space. Because of in the embedded system, treatment resource and memory resource that can be used are all very limited, so when the fingerprint algorithm is transplanted to the embedded system, must trade off in discerning performance and use cost, so the development of the embedded fingerprint recognition algorithm becomes one of the difficult points of product development of fingerprint. The ones that met for using are such as deformation, cast off a skin, rupture, questions such as the scar,etc., question needing overcoming in the fingerprint recognition algorithm.
At present but the embedded fingerprint algorithm is generally developed on DSP platform or ARM platform. The system developed on DSP platform, algorithm performance is stronger, discern the pace is very fast, but the difficulty of development of the algorithm is large, the manufacturing cost is higher. And it is lower to develop the difficulty in system based on ARM, but come up wholly and see discerning pace and result want difference a little, adapt to some application occasions of lower end. See it is still a position of occupying the mainstream of embedded fingerprint recognition algorithm based on DSP platform in the whole market at present.
fingerprint