小波尺度参数对粒子场数字全息重建图像的影响

Effects of Scale Parameter of Wavelet on the Numerical Reconstruction of Particle Hologram

在小波尺度参数取值范围研究的基础上,探讨了小波尺度和粒子衍射波尺度的关系(即衍射波覆盖率),深入研究了小波尺度对重建图像分辨率、景深、信噪比以及粒子图像灰度分布的影响.研究结果表明:当小波函数尺度能够覆盖颗粒衍射波的中心和二环区域时,重建图像的分辨率高、景深小和信噪比高,否则,重建图像质量将无法保证.但是,较大的小波尺度将使重建图像的灰度分布在光轴方向产生振荡,不利于颗粒的空间定位.

The relationship between the wavelet scale and particle diffraction scale is discussed and based on which the effects of wavelet scale on the resolution,depth of field,signal-to-noise（SNR） and gray distribution in axial direction of the reconstructed particle image are extensively investigated.The results show that：high resolution,small depth of field and high SNR of the reconstructed image can be obtained when the wavelet scale is large enough to cover both the center and the second ring area of the particle diffraction pattern.And,the quality of the reconstructed image is poor.But,large value of wavelet scale makes the gray distribution of the reconstructed image in axial direction to be oscillated,which has a negative effect on the identification and locating of particles.