Time since deaht estimation by the method of the three- dimensional-frequency polarizing maping filtering of polycrystalline cerebro-spinal fluid films images

There are many new methods ware researched in recent years for time since death estimation and laser polarimetric techniques are one of the most perspectiv of them. Thay have demonstrated the high accuracy and objectivity of biological tissue investigation for various intervals of post-mortem period. The purpose of the work. The post-mortem interval establishment by statistical analysis of the dynamics changes of coordinate distributions of values polarization azimuth (PA) of the polycrystalline films of liquor (PFL) using the three-dimensional-frequency filtering method of biological multiscale layers investigation. Materials and methods. Objects of investigation are PFL, taken in 67 corpses with accurately known time of death and 6 healthy volunteers. Coordinate distributions of PA image values were estimated for each sample of PFL in the optical arrangement of the Stokes polarimeter using the method of two-dimensional distributions of Stokes-parameters measurement. The value of statistical points of the 1 - 4 th order was perfomed for each two-dimensional distribution of PFL images PE values. Statistical processing of the calculated values of set of points that characterize the PA distributions within representative sampling was carry out. The depending on the time change of the most sensitive points of statistical values were built to achieve values stabilization. Results and conclusions. Optimal interval in 30 hours and the accuracy of the time since death determination 80 min for the large-scale component of polycrystalline films of liquor and optimal interval in 14 hours and the accuracy of the time since death determination 30 min for the small-scale component of polycrystalline films of liquor were established by the method of two- dimensional Stokes-polarimetric mapping of liquor images polarization azimuth values distribution.