Diatom morphological classification method for inferring drowning location in forensic medicine

A diatom morphological classification method for inferring a drowning location in forensic medicine, comprising:

• acquiring diatom vector data and tissue vector data;
• extracting three principal component variables from the diatom vector data and the tissue vector data individually, and representing the three principal component variables as a coordinate point in a three-dimensional space to obtain a first coordinate point and second coordinate points;
• calculating distances between the first coordinate point and the second coordinate points respectively corresponding to sampling sites;
• and
• determining one of the sampling sites corresponding to one of the second coordinate points with a shortest distance to the first coordinate point as a potential drowning location;
• wherein the acquiring diatom vector data and tissue vector data comprises:
• collecting water samples from the sampling sites in a target area, and preparing water sample smears from the water samples;
• counting a diatom quantity in each of the water sample smears of the sampling sites;
• classifying diatoms in the water sample smears by a diatom classification system, and calculating percentages of respective diatom types relative to the diatom quantity in each of the water sample smears;
• arranging values of the percentages of respective diatom types in a predetermined order to obtain the diatom vector data for each of the sampling sites;
• and
• extracting a human tissue sample to be tested, preparing a tissue smear from the human tissue sample, and classifying diatoms in the tissue smear by the diatom classification system to obtain the tissue vector data;
• wherein a process for classifying the diatoms in the water sample smears or the tissue smear by the diatom classification system comprises:
• extracting a diatom frustule feature, an outline feature, and a texture feature for the diatoms from the water sample smears or the tissue smear;
• determining, based on the diatom frustule feature, symmetry classification of the diatoms from the water sample smears or the tissue smear;
• determining, based on the outline feature, outline classification of the diatoms from the water sample smears or the tissue smear;
• and
• determining, based on the texture feature, texture classification of the diatoms from the water sample smears or the tissue smear.