The effect of optical cleaning method combined with laser speckle imaging (LSI) was discussed to improve the detection depth of LSI due to high scattering characteristics of skin, which limit its clinical application. A double-layer skin tissue model embedded with a single blood vessel was established, and the Monte Carlo method was used to simulate photon propagation under the action of light-permeating agent. 808 nm semiconductor and 632.8nm He–Ne lasers were selected to study the effect of optical clearing agents (OCAs) on photon deposition in tissues. Results show that the photon energy deposition density in the epidermis increases with the amount of tissue fluid replaced by OCA. Compared with glucose solution, polyethylene glycol 400 (PEG 400) and glycerol can considerably increase the average penetration depth of photons in the skin tissue, thereby raising the sampling depth of the LSI. After the action of glycerol, PEG 400, and glucose, the average photon penetration depth is increased by 51.78%, 51.06%, and 21.51% for 808 nm, 68.93%, 67.94%, and 26.67% for 632.8 nm lasers, respectively. In vivo experiment by dorsal skin chamber proves that glycerol can cause a substantial decrease in blood flow rate, whereas PEG 400 can significantly improve the capability of light penetration without affecting blood velocity, which exhibits considerable potential in the monitoring of blood flow in skin tissues.

激光散斑图像压缩对降低数据存储量具有重要的意义。设计了一种激光散斑图像无失真编码器,它由激光散斑位移估计、像素预测和Golomb编码组成。首先估计散斑位移;然后,根据激光动态散斑相关函数设计预测模型,并以预测模型为基础进行像素预测;最后,对预测误差进行Golomb编码。该编码器的主要特点包括使用数字散斑相关方法估计散斑位移,以及基于动态散斑相关函数极值的时间预测。实验结果显示,在压缩激光散斑图像时,激光散斑图像无失真编码器在压缩性能方面取得了较大的提高。