本文开发了一套基于声光调制的粒子图像速度粒度场仪成像系统,其中包括双脉冲激光系统和光强调整两部分.该系统选用连续激光器,利用声光调制器对激光束的外调制作用,产生不同光强不同频率的激光脉冲,简化了激光系统,实现了基于灰度统计判别的查询方法;采用数字摄像机记录图像,省略了图像采集卡.光强调整减小了光强的高斯分布对成像质量的不利影响.采用像增强技术,使小功率激光器能够达到与大功率激光器相同的效果,降低了激光器功率的要求.利用该系统对循环水槽模拟水涡流开展了测量,并分析了相应的试验结果.

This paper developed the imaging system of a particle image velocimetry & sizer(PIVS) based on acousto-optic modulator.The imaging system comprises double-pulses laser,laser intensity adjustment,CMOS camera,and signal synchronization unit.The pulsed laser is modulated from a continuous laser and presents an adjustable light intensity and frequency using a external modulation of acousto-optic modulator.The gray-scale classification interrogation method is easily achieved by the flexibility of difference of laser intensity．A CMOS camera is used for the image recording．The intensity modulation improves the negative influence of Gauss distribution on image quality．The application of image intensification decreases the requirement of laser output power and therefore benefits the COSt of the imaging system．The simulated swirl of a circular water-tunnel was measured by this system and the relevant experimental results were analyzed．