光学小波包变换及其滤波器的研究

基于对光学小波变换必要条件的分析，提出光学小波包变换的概念.选出虹膜图库的联合最优小波包基，利用最优基的线性组合生成相应的复合光学小波包滤波器.将滤波器用于光电混合虹膜识别系统中对待识别输入进行小波包特征提取预处理，模拟结果不仅证明引入该滤波器可明显提升系统的识别效果，也证明了光学小波包变换提出的意义.

Research on Optical Wavelet Packet Transform and Its Filter for Iris Recognition

To introduce wavelet packet transform into optical transform and improve the recognition performance of optical iris recognition,optical wavelet packet transform is proposed based on the analysis of the necessary condition for optical wavelet transform.Using the eigen-image based correlation recognition method and replacing the entropy criterion with the identification rate for iris recognition,the joint best wavelet packet bases for the whole image bank are chosen.Corresponding eigen images are generated.To further improve the performance of optical iris recognition, an optical wavelet packet filter is designed through linearly combining these wavelet packet bases.The filter is inserted in a volume holographic opto-electronic hybrid iris recognition system for feature extraction.The wavelet packet features extracted correlate with the eigen images stored in the photorefractive crystal.The correlation results are captured and transferred to a computer for post processing. In simulation,the mother wavelet,Db4,is utilized.Four wavelet packet bases are selected.The filter can obviously improve the identification rate from 90.91% to 95.45%.This result not only proves the efficiency of the filter designed but also shows that the capacity of optical information processing is enhanced after the introduction of wavelet packet transform into optics.