基于Image J软件的血迹遗留时间推断研究

Research on bloodstain age inference based on Image J software

目的探究血迹在非渗透性客体表面的干燥过程,建立基于Image J软件的血迹遗留时间推断方法。方法选取塑料板、玻璃板、漆层木板、瓷砖和铁片5种常见的非渗透性客体作为血迹的承载介质,分析不同靶面血迹干燥特征的时序变化,运用Image J图像处理软件量化分析平均灰度值、血池比率和裂纹比率3项特征性指标与遗留时间的相关性。结果塑料板和铁片表面血迹的平均灰度值变化率较小,裂纹比率较大。塑料板、玻璃板和瓷砖的血池比率较漆层木板和铁片的变化率大。依据血迹的特征量化指标拟合了不同时段血迹遗留时间的回归方程。结论建立了非渗透性客体表面血迹遗留时间的推断方法,可为犯罪现场出血时间的判定提供依据,为智慧警务应用提供技术支撑。

Objective The drying process of blood on the non-porous surface was explored,and the method for inferring remaining time of blood stain based on Image J software was established.Methods Five common non-porous objects,including plastic plate,glass slide,painted board,ceramic tile and iron sheet,were selected as the carrying media of bloodstains.The temporal changes in drying characteristics of bloodstains on different target surfaces were analyzed.Image J image processing software was used to quantitatively analyze the correlation between average gray value/blood pool ratio/crack ratio and the residual time.Results The average gray value of bloodstains on the surface of plastic plate and iron plate has less change rate,while that on the crack ratio is much larger.The ratio of blood pools in plastic plate,glass slide and ceramic tile changed more significantly than that in painted board and iron sheet.According to the characteristic quantification index of bloodstains,the regression equations of bloodstains in different periods were established.Conclusion A method of predicting the age of bloodstains on non-porous object surfaces was established,which can provide a basis for judging the bleeding time on crime scene and provide technical support for the application of intelligent police management.