激光微粒影象的粒径判读准则

1.引言 在许多工程及科学领域中,微粒尺寸及分布的测量是很重要的。在诸类测粒方法中,摄影测粒技术尤受重视。因为摄影方法可将结果长期保存,记录信息量大,测量结果直观易于分析。当以脉冲激光照明进行摄影时,还能将高速运动的微粒“冻结”下来,完全可视作静态处理。激光摄影测粒技术有激光显微摄影和激光全息摄影,二者最后都转化为从

THE CRITERION OF DETERMING PARTICLE SIZE WITH LASER COHERENT IMAGING

The coherent imaging process of particles and the determination of particle size from their coherent images are discussed in this paper. An experimental investigation on the characteristics of coherent images of particles has been taken. It is concluded that when recording far-field number is small, the size of the particle can be measured directly by its coherent image. Using two dimensional discrete Fourier transform (DTF), a theoretical calculation of the intensity of the coherent image of a particle has been taken. Depending on the experimental and calculated results, it is found that when recording far-field number is less than 0.3 the particle size can be determined directly by the coherent images.