基于标准互相关函数的图像分辨率自动标定方法

理想规则图像特征经标准互相关函数匹配后,相似函数C*(x)可用确定的解析式Z(x)表达.但是对于含噪声图像,相似函数C(x)较之C*(x)发生了变化,但存在"零相似不变性".将此原理应与于显微视觉中图像物面分辨率的在线标定,推导了矩形图像特征的一维相似函数解析式Z(x);求解C(x)=0作为Z(x)的近似,并给出了具体标定算法;通过仿真图像实验,给出标定算法的正确度在0.1～0.2 pixel;最后,将标定算法应用于可连续变焦的微对准装配系统,实测算法的精密度可达为0.08 pixel.实验结果表明,基于"零相似不变性"的标定算法是具有实用性的亚像素标定方法.～290nm波长激发下,310～390nm范围内产生荧光光谱,峰位波长在350nm,最佳激励波长为250nm;采用垂直偏振片(起偏角为0°)起偏照射样品,发现偏振荧光峰位不变,荧光峰强度随检偏角的增大而呈明显的线性递减关系.由实验数据计算得到荧光偏振度为0.783,表明分子具有一定确定取向;另外,分析认为酸性橙Ⅱ产生荧光,是由于分子中含有苯环和萘环结构吸收紫外光能量,以及氮键在光子作用下形成顺式异构体的激发单线态后,两者发射的光子所致.整个结果对酸性橙Ⅱ在食品中的违禁使用检测、特性表征、以及分子规律的更深入研究,有一定的参考价值.

A Method of Image Resolution Calibration for Automatic Microscopic Zooming Based on NCCO

Pattern matching tool of normalized cross correlation operator (NCCO) computation C*(x) for ideal images can be determined by analytical expression Z(x). Compared with C*(x), C(x) of NCCO matching between images containing noise shows a little difference. But there is a property of zero similarity invariance (ZSI). A method of image resolution calibration in microscopic vision was proposed. Firstly, similarity functions of rectangular feature in x direction Z(x) were derived and proved. Then C(x)=0 was solved as an approximation of solution of Z(x). The detailed ZSI based calibrating algorithm was illuminated. The results of simulating image experiments show that the calibration accuracy of the algorithm can reach 0.1～0.2 pixel. Finally, the practical experiments were conducted on a hybrid microassembly workcell. Experimental results show that the calibration precision of the algorithm can reach 0.08 pixel. The ZSI based calibrating algorithm is a method with practical value and subpixel precision.