POST-MORTEM INTERVAL ESTIMATION BY CEREBRO-SPINAL FLUID FILMS POLARIZATION IMAGES OPTICAL STRUCTURE CHANGING

INTRODUCTION: Post-mortem interval (PMI) estimation has been and remains one of the main issues of forensic medicine. Complex photometric, polarization, and correlation techniques of biological tissue (BT) structure are crucial in this area. OBJECTIVES: The purpose of this study is to develop and test two-dimensional Stokes-polarimetric mapping of biological layers to evaluate the accuracy of PMI assessments using statistical analysis of post-mortem changes and dynamics of the coordinate distributions for the polarization ellipticity (PE) images of polycrystalline films of liquor (PFL). Coordinate distributions of polarization ellipticity (PE) 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. RESULTS: The most sensitive statistics to the post-mortem manifestations in terms of changes to liquor polycrystalline optical networks were those for the 3rd and 4th order. They characterized asymmetry and kurtosis (peak sharpness) of coordinate distributions for polarization ellipticity images of polycrystalline films of liquor. The optimal interval was 32 hours, with accuracy of 60 min, from the method of two-dimensional Stokes-polarimetric mapping used.