光电混合联合变换相关器中各元器件结构参数之间的关系

Relationship between parameters in hybrid optical/electronic joint transform correlator

分析了空间光调制器(SLM)和面阵CCD的像元结构对输入图像和功率谱的抽样,以及抽样对光电混合联合变换相关器(JTC)性能的影响;推导出了光电混合JTC中,SLM、面阵CCD、傅里叶变换透镜、输入图像等各结构参数之间应满足的关系。根据推导出的关系公式,结合实验所用透镜、SLM、CCD的各项参数,选择不同的图像间距,对联合变换相关识别过程进行了模拟验证。输入大小都为32×32像素的参考图像和目标图像,当两者间距大于64像素且小于374像素时,可以得到理想的识别效果;间距小于64像素时,同级输出光场的自相关和互相关信号不能完全分离;间距大于374象素时,相邻两级互相关信号交叠错位;当间距大到超过405像素时,无法进行相关识别。模拟结果与理论推导一致。这些关系对JTC的设计及应用有重要意义。

Based on the grid pixel structure of spatial light modulator (SLM) and CCD used in a hybrid optical/electronic joint transform correlator (JTC), the relationship among the structure parameters of SLM, CCD, Fourier transform lens and input images are presented. According to the relations, the JTC recognition processes are simulated with different distance between the object and the reference image which are equal in size: 32 × 32 pixels. When the distance of the two input images is 64 pixels to 374 pixels, a perfect recognition result can be obtained. When the distance is less than 64 pixels, self-correlation peak and cross-correlation peak in the same order output signals can not be separated completely. The distance of more than 374 pixels results in the overlap of adjacent of correlation signals, and when the distance is more than 405 pixels, the JTC can not recognize the two input images. These simulation results have proved the theoretical analysis. The relationship is important to the configuration and application of JTC.