| Laser speckle imaging is a two dimensional blood flow detection technology in living tissues, which is widely concerned in recent years. It is applied in the basic research of life science and disease diagnosis. The electric field decorrelation time of the scattering light in the turbid medium is obtained by laser speckle contrast analysis, and the velocity of the scattered medium is related to the decorrelation time. The Brownian motion and the single scattering model was used in previous studies, the relationship between the laser speckle contrast and the scattering electric field decorrelation time was built by the autocorrelation function of Lorenz spectrum. However, the scattering characteristics of the biological tissue and the form of the blood flow are very complex, and the simple approximation makes the laser speckle imaging difficult for quantitative detection of the blood flow. In order to improve the accuracy of blood flow quantitative detection in laser speckle imaging, it is necessary to find out the form of electric field autocorrelation function in complex biological tissue, and then we can obtain more accurate movement information of the scatters by speckle contrast analysis. In response to these needs, combining with the dynamic particle system and the electric field Monte Carlo method, this paper realized the characteristic of back scattering light field simulation when coherent light transmitted in different dynamic turbid medium. The main contents of this paper are showed as bellow:1)The electric field autocorrelation function of scattering light in different dynamic turbid medium used in the laser speckle blood flow imaging was compared and analyzed, and their application situation was listed and the result was proofed by experiment. The electric field autocorrelation function containing the static component was analyzed, and give out the solving method of multi exposure speckle analysis, the validity of the method is verified by the model experiment results.2)Simulated the coherent light transmission in dynamic medium model, Dynamic media EMC(DMEMC) simulation was based on particle system and EMC method. The particle system simulation realized the simulation of Brownian motion media, ballistic motion media and static media, GPU accelerated Monte Carlo simulation realized the process of coherent light transmission in the medium.3)Research on the characteristic of back scattering light field transmit in dynamic turbid medium by DMEMC method, the scatters of medium can do Brownian motion ballistic motion and hybrid motion. |
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