Font Size: a A A

Study Of Multi Modal Biometric Fusion Method Under Non-contact Conditions

Posted on:2016-04-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y H TangFull Text:PDF
GTID:1108330482475737Subject:Measuring and Testing Technology and Instruments
Abstract/Summary:PDF Full Text Request
Some physiological structure of the human body, or called biometrics, such as face, iris, fingerprint, hand geometry, palmprint, unique, is invariant in a fairly long period of time. And it is not to be lost and not to be forgotten. In recent years, the biology characteristics of human body has been used to replace easily lost or imitation keys, ID, easily forgotten or stolen password and so on, in some occasions more and more.Adn it has played more and more important role in daily life and production of public security and people’s.Multimodal biometric recognition is a biometric identification technology based on information fusion technology, which is the application of "learn from each other, the advantage is complementary" thought. Multimodal biometric recognition technology can effectively improve the overall performance of the biometric system, which has very strong robustness, and can achieve the quality of single biometric unable or very difficult to achieve. In this paper, taking the hand multimodal biometrics as the main research contents, using self-made hand multimodal image acquisition device as the foundation, proposed the solution of embedded hand multimodal fusion problem. In this paper, the main work is as follows:Firstly, according to the characteristics of biological characteristics of hand in hand shape, palm, palm vein image by image acquisition device characteristics can be one-time can be acquired, based on comprehensive analysis of palmprint and palm vein imaging principle, double CCD hand multi modal image acquisition device is produced, which can be used to validate the pattern recognition of hand multi-mode algorithm. The device is equipped with infrared LED includes a plurality of bands in the visible and multi wavelength multi spectral light source, and the wavelength of the LED light source can flexibly adjust the luminous intensity. Dual CCD camera can be in more than one band of LED, respectively, at the same time access to the palmprint and palm vein image. The device can conveniently obtain the hand three modal images of samples, the establishment of the corresponding Gallery, validates the fusion recognition method. In order to be able to be better hand multimodal biometrics methods used in our daily life, hand dual camera embedded system of multi modal image acquisition and processing system is developmented. Low resolution hand multi modal image can be obtained through the system, and it has the possibility for the practical application of hand multimodal biometric modality. At the same time, in order to effectively reduce hand multimodal image acquisition required LED extended source size, while ensuring the uniformity of irradiation to the whole palm light, this paper proposes the construction of small size LED extended source using finite high brightness LED, and then through the lens extends two distribution of light source on small LED, finally it will make the light intensity be sufficient and uniform objective. Based on the analysis of the two distribution of light, with theoretical ray tracing simulation and experiment, the quite ideal effect is be obtained.Secendly, according to the characteristics of non- contact conditions acquisition palmprint and palm vein image texture, palmprint palm vein fusion method is be proposed. Firstly, the full hand image of palmprint and palm vein will be normalized for size and direction, and then extract ROI images from full hand palmprint image. Since the time of multi modality image acquisition is very short, multi modal image no shift in space, so the palm vein image ROI can be directly extracted according to the ROI palmprint image coordinate. The palmprint ROI images and palm vein image ROI images were normalized to gray. According to the characteristics of different direction and width of local minimum values of texture, the texture structure will be extracted. Then according to the corresponding relationship of palmprint and palm vein texture under different circumstances, texture fusion will be made respectively. Finally, the fused image will be identificated. The experimental results show that the palmprint recognition effect of the fused image recognition effect is better than the single mode and palm vein recognition effect, through the self-made double CCD hand multimodal image acquisition device.Thirdly, according to the characteristics of palmprint and palm vein image from the double CCD hand multimodal images non contact acquiring device, wavelet transform fusion method is proposed based on palmprint and palm vein. ROI of palmprint and palm vein image from double CCD will be extracted and registration pretreated firstly. Then according to the pre-selection wavelet, palmprint ROI and palm vein ROI images were multilevel wavelet decomposition. Then the high frequency and low frequency coefficients of the palmprint and palm vein are fused according to different strategies. Finally the fused image is obtained through inverse wavelet transfer. The experimental results show that, recognition effect through the fused images is better than single modal palmprint recognition and single mode of palm vein recognition, and is better than other fusion methods.Fourthly, for data processing capacity of embedded hand multimodal image acquisition and processing system is limited, join the hand shape recognition based on data fusion on the palm and palm vein. First use of hand shape recognition mode speed advantage, through dual threshold appropriate to identify objects into three categories: identity confirmation classes, classes and unknown identity veto. Then according to the recognition of the objects of the category, to decide whether or not to perform wavelet transform fusion recognition based on palmprint palm vein. The experimental results show that, through the comprehensive utilization of three hand hand identification mode, the average time in embedded system is greatly shortened; the recognition effect is obviously improved.
Keywords/Search Tags:Hand multimodal imaging, Data fusion, Wavelet transform, Embedded system
PDF Full Text Request
Related items