共查询到20条相似文献,搜索用时 93 毫秒
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光电混综合判别相关器 总被引:1,自引:0,他引:1
论述了综合判别函数的基本理论,简明地给出了用综合判别函数实现畸栾不变相关的技术途径。在此基础上,构造了一个光电混合综合判别相关器实验系统,并用它实现了三重畸变不变实时相关识别。 相似文献
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提出利用线性判别函数,d(x)=W'x,对轰炸机和战斗机两类目标进行旋转不变识别。每一目标有72个旋转模式,其中9个为训练样本,63个为测试样本,在每个目标的训练样本中随机取一个相减作为线性判别函数的系数(Wij)的初始值,然后利用误判的训练样本优化判别函数的权值以提高函数的正确识别率。为便于光电实现,线性判别函数的权值系数只有2、1、0、-1、-2五个值。计算机模拟表明利用此判别函数进行分类的正 相似文献
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基于光学子波变换的SDF匹配滤波器 总被引:2,自引:1,他引:2
提出了一种基于光学子波变换的综合判别函数匹配滤波器(WFSDF),将光学子波变换和综合判别函数相结合,只用一个简单的4f系统就能实现输入图像和SDF子波变换的相关运算。采用计算全息的方法制作复数匹配滤波器。计算机模拟仿真结果表明,与传统的SDF匹配滤波器相比,WFSDF匹配滤波器,锐化了相关峰,提高了识别率,同时简化了光路,能够实现多目标的畸不变识别。 相似文献
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从分数傅里叶变换(FRFT)的定义出发,理论分析了联合分数变换相关器(JFRTC)的分数相关特性.从所得JFRTC的数学表达式中可以看出,将FRFT应用到联合变换相关器(JTC)中得到的JFRTC具有与传统JTC不同的性质.对于传统JTC,一旦输入平面上参考图像与目标图像之间的距离给定,相关输出峰的位置即确定,而JFRTC的相关输出峰的位置则可以由分数级次p1和p2来自由调节,这个特性在实际模式识别中非常有用.另一方面,JFRTC的相关输出峰值在大多数情况下低于传统JTC的相关峰值,却是JFRTC的一大缺点.最后,从FRFT的比例性质出发,给出了FRFT谱畸变不变的实现条件,并由此预言了JFRTC畸变不变模式识别的功能. 相似文献
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用相关矩阵特征判据法实现三重不变光学图像识别 总被引:1,自引:0,他引:1
本文首先在K-L变换中用相关矩阵作为特征判据进行特征压缩,然后用综合判别函数法制备空间综合匹配滤波器,可以有效地压缩特征图像数目.用这种滤波器实现了平移、旋转、尺度三重不变光学图像识别,且有较高的信噪比. 相似文献
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介绍一种用动态滤波及统计相关数据处理的滤波器设计方法。光学一数字混合系统使用该滤波器用于畸变(平移、比例、旋转、强度)不变目标识。计算机仿真和实验证明该系统对大的畸变范围具有检测识别目标的能力。还给出多目标识别的数值模拟。 相似文献
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应用联合变换相关器对目标进行探测和识别时,由于实际探测到的目标相对于参考图像存在比例、旋转、平移畸变,因此在传统的光学相关器中很难实现目标的探测和识别。为了更好地探测到目标,提出了面积-极坐标的算法,该算法利用相似图形之间的尺寸与面积存在满映射函数关系,实现了比例不变光学探测,并结合极坐标变换实现旋转不变光学探测,最后,对变换后的联合图像进行小波边缘提取,既能提取到清晰的图像边缘,又能有效地抑制噪声,不但提高了相关峰,并使得相关峰更为尖锐,成功实现了大尺度混和畸变目标的探测和识别。作为实例,对混合畸变目标进行了计算机模拟和光学实验,验证了该算法在大尺度混合畸变光学相关探测中的可行性。 相似文献
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四元量化的综合鉴别函数滤波器实现比例不变相关识别 总被引:2,自引:2,他引:0
设计一种基于综合鉴别函数(SDF)的比例不变相关识别滤波器,将频域中被SDF调制的相关输出函数进行复数形式的四元量化(QFCQ),并采用叠代算法调整SDF的系数,使输出的相关峰尖锐,区分能力强,同时满足不同比例图像等相关峰输出的准则,从而达到了比例不变识别的要求.计算机仿真实验对属于训练图像系列的目标图像进行了识别,并与基本的SDF及二元化纯相位SDF做了比较,结果表明该方法具有较好的识别效果. 相似文献
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Chau-Jern Cheng 《Optical Review》2001,8(6):431-435
An image-encrypted joint transform correlator for pattern recognition is proposed and evaluated. The correlator performs twofold
correlation for recognizing the primary image and cipher, and the encrypting cipher acts to enhance or inhibit the correlation
peak if the cipher is correctly input. By incorporating the original image with an appropriate cipher, the correlator achieves
better pattern discrimination and is robust against distortion. Simulation results show that the pixel number and the cell
size of cipher affect the characteristics of the correlator. 相似文献
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Optical means of performing pattern recognition possessing shift-, rotation- and limited size-invariance is demonstrated. The experimental set-up is a standard Fourier transform correlator with a binary circular harmonic (CGH) filter. The filtering function of the filter is obtained by the synthetic discriminant functions (SDF) method. In the process of synthesizing the filtering function, circular harmonic functions are chosen as the basic functions. Both optical results and computer simulation results demonstrate that the filter is able to recognize the target in every rotational orientation and in the relative size range of 1–1.82. 相似文献
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Chung J. Kuo 《Optical and Quantum Electronics》1994,26(9):941-948
The theoretical analysis for a nonlinear and bipolar frequency-selective joint-transform correlator is reported without any impractical assumptions and verifield. The theoretical results are similar to those for a nonlinear and bipolar joint-transform correlator. In addition, the optimal threshold value for a bipolar frequency-selective joint-transform correlator is found to be zero. Moreover, a bipolar frequency-selective joint-transform correlator can provide a phase-only correlation signal with delta-function shape. The theoretical study for a DC-block bipolar frequency-selective joint-transform correlator is also given. It is shown that its autocorrelation peak remains the same as that without a DC block. 相似文献
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In this work an optical-digital correlator for pattern recognition and input scene restoration is described. Main features of the described correlator are portability and ability of multi-element input scenes processing. The correlator consists of a consumer grade digital photo camera with a diffractive optical element (DOE) inserted as a correlation filter. Correlation of an input scene with a reference image recorded on the DOE are provided optically and registered by the digital photo camera for further processing. Using obtained correlation signals and DOE’s point spread function (PSF), one can restore the image of the input scene from the image of correlation signals by digital deconvolution algorithms.The construction of the correlator based on the consumer grade digital photo camera is presented. The software procedure that is necessary for images linearization of correlation signals is described. Experimental results on optical correlation are compared with numerical simulation. The results of images restoration from conventionally and specially processed correlation signals are reported. Quantitative estimations of accuracy of correlation signals as well as restored images of the input scene are presented. 相似文献
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An encrypted holographic scheme with a compact alignment system for a phase key is proposed. Alignment for a phase key is performed by a holographic correlator. A filter in the correlator system contains the phase information used for encryption. Thus, it can be used to check the authorization of the phase key. Owing to the shift-invariant property of the holographic correlator, the location of the correlation peak is highly related to the alignment of the phase key. Therefore, the phase key can be repositioned on the desired location by searching for the specific position of the correlation peak. With the help of the correlator, alignment of the phase key can be done in 1 min. Experimental results using a correlator system in support of our proposed idea are demonstrated as well. 相似文献
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Performances of an all-optical subtracted joint transform correlator that uses a photorefractive crystal 总被引:1,自引:0,他引:1
An all-optical subtracted joint transform correlator (JTC) was proposed and it was experimentally shown that the correlator successfully performs the pattern recognition with the number of reference patterns. In the correlator, an optical interferometer was introduced to remove the additional correlation signals between the reference patterns themselves from the output plane and a photorefractive crystal was also introduced to record the joint power spectra as volume holograms. The processing for removing the additional correlation signals was performed by the parallel computations in the interferometer in real time. In this study it has been found that the correlator yields significantly better correlation results than the classical joint transform correlator does and the recording of the volume hologram corresponds to a nonlinear processing of the joint power spectrum in the fringe-adjusted joint transform correlator. However the volume hologram has angular selectivity for matching the Bragg condition. It would restrict the shift-invariant area of the input image plane. This restriction has been investigated experimentally. 相似文献