基于小波变换的匹配滤波器优化设计及应用研究

发布时间：2019-02-12 06:37

【摘要】：小型集成化和优异稳定的识别性能是光学相关器发展的两个关键,本实验室提出利用纯相位数字微透镜代替物理透镜构成平面集成2f光学相关器,以压缩体积、提高了系统的集成度,但识别率有所降低。为提高系统的识别性能,考虑到OTSDF匹配滤波器在光学相关器的畸变不变识别应用中良好的识别效果,本文提出基于小波变换的OTSDF滤波器(W_OTSDF)算法,对其进行了优化设计,将优化设计的W_OTSDF滤波器应用于平面集成2f光学相关识别系统开展理论和实验研究,利用小波变换的多尺度与带通滤波特性,提高了系统进行相关识别的相关输出峰值强度和信噪比(SNR)。数值仿真验证了该优化设计方案的可行性,实验上搭建实际光路在空间光调制器(SLM)上加载该匹配滤波器,实现了对待识别目标的畸变不变识别。本论文的主要研究工作如下:(1)将小波变换与OTSDF相结合,提出了W_OTSDF滤波器的优化设计算法。通过对小波变换和匹配滤波的理论分析,设计了适合平面集成2f光学相关识别系统,能提高对畸变不变目标识别的效果的W_OTSDF滤波器算法。(2)建立了平面集成2f光学相关器的仿真模型。基于平面光学传递函数理论和平面集成2f光学相关器系统结构参数限制,确定了系统的结构参数,建立了系统的MATLAB仿真模型,利用菲涅耳衍射和透镜的相位调制特性模拟了平面集成2f光学相关器的识别过程。(3)将本文提出的W_OTSDF滤波器算法应用于平面集成2f光学相关器中,自编程序模拟分析结果表明,优化后的W_OTSDF滤波器比原OTSDF滤波器具有更好的识别效果。W_OTSDF滤波器在识别旋转、缩放、旋转缩放同时存在的畸变目标时,峰值相关能量比(PCE)、峰值旁瓣比(PSR)、SNR整体性能指标与OTSDF滤波器识别性能指标相比均有较大提高。同时对W_OTSDF滤波器的性能改善的机理进行了分析。(4)搭建了平面集成2f光学相关器的等效实验光路,实验结果与仿真分析基本一致。在SLM上加载设计的W_OTSDF滤波器来验证滤波器对畸变目标的识别效果,实验结果表明:对[-48°,+44°]范围内的旋转畸变目标、[60%,148%]的缩放畸变目标以及同时存在旋转角度为[-32°,+36°]和缩放尺度[72%,134%]的畸变目标,该匹配滤波器都有较好的识别能力。本文优化设计的W_OTSDF滤波器较OTSDF滤波器在峰值相关能量比(PCE)、峰值旁瓣比(PSR)、SNR整体性能指标均有较大提高,具有更好的识别效果,有利于提高集成化相关器系统的识别能力,该滤波器的优化设计方案可普遍适用于平面集成化光学相关器系统,对光学模式识别领域的发展和推进光学相关器的实用化有一定的研究意义及应用价值。
[Abstract]:Small-scale integration and excellent stable recognition performance are the two key points in the development of optical correlator. In order to compress the volume of optical correlator, we propose to use pure phase digital microlens instead of physical lens to form planar integrated 2f optical correlator. The integration of the system is improved, but the recognition rate is reduced. In order to improve the recognition performance of the system, considering the good recognition effect of the OTSDF matched filter in the distortion invariant recognition of optical correlator, this paper presents the OTSDF filter (W_OTSDF) algorithm based on wavelet transform, and optimizes its design. The optimized W_OTSDF filter is applied to the planar integrated 2f optical correlation recognition system for theoretical and experimental research. The multi-scale and band-pass filtering characteristics of wavelet transform are utilized. The correlation output peak intensity and signal-to-noise ratio (SNR).) of the system for correlation identification are improved. The feasibility of the optimal design scheme is verified by numerical simulation. The actual optical path is constructed to load the matched filter on the spatial light modulator (SLM), and the distortion invariant recognition of the target is realized. The main work of this thesis is as follows: (1) combining wavelet transform with OTSDF, the optimal design algorithm of W_OTSDF filter is proposed. Based on the theoretical analysis of wavelet transform and matched filtering, a plane integrated 2f optical correlation recognition system is designed. The algorithm of W_OTSDF filter can improve the recognition effect of distorted invariant target. (2) the simulation model of planar integrated 2f optical correlator is established. Based on the theory of planar optical transfer function and the limitation of structural parameters of planar integrated 2f optical correlator system, the structural parameters of the system are determined, and the MATLAB simulation model of the system is established. The recognition process of planar integrated 2f optical correlator is simulated by using Fresnel diffraction and phase modulation characteristics of lens. (3) the proposed W_OTSDF filter algorithm is applied to planar integrated 2f optical correlator. The simulation results show that the optimized W_OTSDF filter has better recognition effect than the original OTSDF filter. When the W_OTSDF filter is used to identify the distorted targets which exist at the same time as rotation, scaling and rotation scaling, the optimized W_OTSDF filter is better than the original OTSDF filter. Peak correlation energy ratio (PCE),) peak sidelobe ratio (PSR), SNR) is higher than that of OTSDF filter. At the same time, the mechanism of improving the performance of W_OTSDF filter is analyzed. (4) the equivalent experimental optical path of planar integrated 2f optical correlator is built, and the experimental results are in good agreement with the simulation analysis. The designed W_OTSDF filter is loaded on the SLM to verify the effect of the filter on the distortion target recognition. The experimental results show that for the rotating distorted target in the range of [-48 掳, 44 掳], [60], The scale distortion target of 148% and the distortion target with rotation angle [-32 掳, 36 掳] and zoom scale [722 / 134%] both have good recognition ability. Compared with the OTSDF filter, the W_OTSDF filter optimized in this paper improves the overall performance of the (PCE), peak sidelobe compared with the (PCE), peak sidelobe, and has a better recognition effect. It is helpful to improve the recognition ability of the integrated correlator system. The optimal design scheme of the filter can be widely used in the plane integrated optical correlator system. It has some research significance and application value for the development of optical pattern recognition and the practical application of optical correlator.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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