Laser speckle contrast imaging (LSCI) is a powerful tool for monitoring blood flow changes in tissue or vessels in vivo, but its applications are limited by shallow penetration depth under reflective imaging configuration. The traditional LSCI setup has been used in transmissive imaging for depth extension up to 2lt–3lt (lt is the transport mean free path), but the blood flow estimation is biased due to the depth uncertainty in large depth of field (DOF) images. In this study, we propose a transmissive multifocal LSCI for depth-resolved blood flow in thick tissue, further extending the transmissive LSCI for tissue thickness up to 12lt. The limited-DOF imaging system is applied to the multifocal acquisition, and the depth of the vessel is estimated using a robust visibility parameter Vr in the coherent domain. The accuracy and linearity of depth estimation are tested by Monte Carlo simulations. Based on the proposed method, the model of contrast analysis resolving the depth information is established and verified in a phantom experiment. We demonstrated its effectiveness in acquiring depth-resolved vessel structures and flow dynamics in in vivo imaging of chick embryos.

为实现远距情况下的实际应用, 对赝热源鬼成像进行了从透射到反射的实验研究.首先利用CCD的两个独立区域分别探测参考光和信号光, 得到双缝的透射型鬼成像, 继而利用一个CCD和一个独立的桶探测器分别探测参考臂和物臂的光强信息, 通过对没有空间分布的物臂光强和没有经过物体而有空间分布的参考臂光强信号进行关联计算实现透射和反射鬼成像.为设计和研制能进行现场应用的样机系统, 以透射结构为例, 对成像结果与系统各参数之间的关系进行了详细的对比实验研究, 结果表明通过增加采样率、增大光强、适当调节快门时间和光阑大小可以提高成像的分辨率和可见度.