Linear Scan Palmprint Image Acquisition System Design And Implementation

Pamlprint recognition is used for identification with valid information from people's palmprint. People's palmprint is unique, so it can be used for identification. It is thought to be one of the best secure keys in the information society. This technology has getton more and more focus from international academic community, companies, government and national defense department. Palmprint acquisition system is the basis of the palmprint recognition system and a good palmprint image can provide a good result for following image process. Palmprint acqusition system is mostly constructed by array CCD cameras and the system is too big to reach a smaller size because of the big size of array CCD camera. This paper introduces three kinds of new palmprint acquisition systems that are constructed by linear CCD camera, which can resolve this difficult problem. The main content of this paper is as follows:Movement linear scan palmprint acquisition system, this system uses linear CCD to acquisition palmprint image drived by fixed frequency external signal. Palmprint image gotten by it has a high resolusion. However, this system is too big to meet our need, so it is only used to give a standard to evaluate the following systems.Roller linear scan palmprint acquisition system, this system is constructed by a smaller linear CCD camera and acquires palmprint image drived by external frequency conversion signal, which is synchronous with the speed at which the palm slide on the device provided by system. It is very small and meets our need, the palmprint image gotten by it has a identifiable main line. However, the CCD camera has a poor quality and will produce supersaturated result.Improved Roller linear scan palmprint recognition system, compared with the above system, it improves in three sides. One is that it substitutes direct optical path with reflection light path and reduce the distance of optical path, the second is that it adds a control module which can control the external signal, so the number of external signal system gotten can be twice as much as the above system or half of that. The last is that the system uses a new linear CCD camera which resolves supersaturated problem. Palmprint image gotten by system has a high resolution and identifiable texture.There are two innovations in this paper, the first is that the linear CCD camera is firstly used in acquisition palmprint image; the second is that the synchronized problem occurred in the process that the system acquisitions palmprint image drived by external signal is resolved.