摘要基于干涉粒子成像(IpI)测量公式,分析了影响IPI系统中最大和最小可测粒子尺寸以及粒径测量精度的因素。对一给定的CCD、成像透镜、入射光波波长、光束宽度,分析了物距和离焦距离对粒子干涉条纹图大小的影响,进而分析了对粒径测量精度和可测范围的影响。得出了在满足测量范围要求的条件下,尽量采用相对较大的收集角,干涉条纹图尺寸越大,粒径测量误差越小,但必须考虑条纹图重叠,且对条纹间距进行插值得到亚像素精度,给出了对标准粒子测量实验光路系统设计实例和测量结果。
According to the measurement equation of interferometric particle imaging(IPI), the influence factors including the maximum and the smallest measurable particle diameters and its measuring accuracy of particle diameter, are analyzed in IPI optical system. For the given CCD, imaging lens, wavelength of illumination light and the thickness of the laser width, the influence of the object distance and defocusing distance on the size of the interference pattern of a particle is thoroughly analyzed, the measuring accuracy and the measurable range of particle size are then investigated. The result is that the relatively larger collection angle should be used as much as possible on the condition that the requirements of the measurable size range are satisfied. The larger the size of the interference pattern, the smaller the measuremental error of particle size with the finger overlap considered, and the sub-pixel accuracy of the number of fringes/finger spacing is acquired by interpolation. The optical system design example and its test results of the standard particle are given.