微纳级示踪粒子图像灰度与粒径量化关系研究

Research on Quantitative Relationship Between Image Gray Value and Particle Diameter of Micro-Nano-Scale Tracer Particle

基于传统粒子追踪测速(PTV)技术的粒径分析方法只能通过几何成像检测粒径,无法对衍射成像尺寸远远大于几何成像尺寸的粒子图像进行分析。根据衍射成像原理,通过对激光-粒子散射光-CCD信号-图像灰度值物理流程的定量分析,提出确定微纳米级示踪粒子图像灰度值与粒径之间量化关系的模型,弥补了PTV技术在粒径检测方面的不足。基于PTV实验系统,应用数字相机和Micro Vec V3软件完成SiO2粒子图像的拍摄,运用所提模型对拍摄的粒子图像进行粒径分析。实验结果表明,所提方法具有较高的准确性。

Particle diameter analysis method based on traditional particle tracking velocimetry(PTV) technology can be used to detect particle diameter only by geometric imaging, and it is impossible to analyze particle images when diffraction imaging size is much larger than geometric imaging size. Based on the principles of diffraction imaging, a quantitative relationship model for determining image gray value and particle diameter of a micro-nano-scale tracer particle is proposed through the quantitative analysis of the whole physical process related to laser, particle scattered light, CCD signal, and image gray value and thus the shortcomings of PTV technology in particle diameter detection are addressed. Based on the PTV experimental system, the digital camera and software of Micro Vec V3 are used to complete the shooting of SiO2 particle images, and the proposed model is used to analyze particle diameter from the captured images. The experimental results show that the proposed method has a high accuracy.