【摘要】 首先推导出光学４Ｆ系统的一般衍射变换公式，用不透明圆盘模型算出了象平面附近三维空间内的光强分布。根据计算结果，定义了象的归一化半径和象的变缘锐化率，给出了它们与粒子离物平面远场数之间的关系，从而定量地得出成象区、失真区和远场区的物理图象。最后，对粒子场测量中的粒径和空间位置测量的最小误差作了讨论。这些结果，对分析粒子的大小和分布是十分重要的，并在喷嘴雾化场测试中得到了应用。更多还原

【Abstract】 In this paper,we have deduced the general diffraction transformation formula in optical 4F system,and calculated the optical intensity distribution near the imaging plate over three-dimensional space with obstacle disk model. The normalized radius and the edge sharpness for particle image are defined,and thus the relation among the normalized radius,the edge sharpness and the far-field number of particles can be calculated. Then the position of the survey plate that lies in image region or distortion region or far-field region could be determined. At the end,the minmum error of particle radius and particle position also have been discussed. All above results are very important for particle size and distribution analysis. And these results have been successfully applied to measure the droplet field of nozzle atomization.更多还原