数字全息粒子图像测速技术研究

Research of digital holography PIV technique

通过全息照相及再现的理论分析 ,进行了数字全息计算机数值模拟 ,利用快速傅里叶变换技术 (FFT)对拍摄到的干涉条纹进行了图像复频域的信号分析 ,实现了数字全息的复频域滤波技术和全息图的小景深再现技术 ,应用于数字全息粒子图像测速DHPIV(DigitalHolographyParticleImageVelocimetry)技术 .并对立方体对角复杂流动流场进行了试验测量 ,得到了空间中的三维速度向量场分布 ,进而得到了三维流线的空间分布 。

The principal formula of digital holography was deduced and verified from the analysis of holography using Hugeness-Fressnel theory and computer simulation. The thin focus depth of reconstructed 3-D digital image using in holography particle image velocimetry (PIV) was created by a digital image phase filter method. The velocity vector field with 3-components in 3-D space was computed by 3-D cross-correlation algorithm with thin depth image slices after using phase filter and nonlinear image filter. The 3-D vector and streamline resulting in a cubic flow field were achieved by using DHPIV technique. The results demonstrated an important step was made for the practicality of holography PIV.