Treffer: 死后角膜数字图像变化与死亡时间关系的实验性研究.

Objective To discuss the color changes in postmortem corneal digital images measured by digital image processing and provide a feasible method for quantitatively estimating the postmortem interval( PMI) . Methods After death by hanging，rabbits were placed in a dark room at temperature 20 ℃. A custom-made“ postmortem corneal image acquisition system” was used to acquire corneal images of the rabbits at one-hour intervals within 72 hours after death. The corneal-pupil region in the images were segmented using MATLAB software，and the values of the six color features of R，G，B，H，S，and V were extracted. Next，the regression equations that reflect the relationship between the parameters and PMI were established. Finally，the regression equation with the highest coefficient of determination was selected to perform verification experiments. Results R，G，and B were significantly correlated with PMI( P < 0.01 or P < 0.05)， and there was no significant correlation between H，S，V and PMI( P > 0.05)；R had the highest correlation with PMI( R2 = 0.935)，and no intra- and inter-individual variations of CON values were observed( P > 0.05) . The verification experiment results indicated that changes in the ambient temperature and humidity around the cadavers resulted in changes in the error range of the estimated PMI. Conclusion Postmortem corneal digital image acquisition and digital image processing were used to detect the color changes in the corneal-pupil region images. These color changes can provide an objective and quantifiable method for PMI estimation. [ABSTRACT FROM AUTHOR]

目的 探讨利用数字图像处理技术检测家兔死后角膜数字图像颜色变化，客观量化分析死亡时间( PMI) 的可行方法。 方法 家兔缢死后置于20 ℃室内环境，死后72 h内每间隔1 h应用自制的“死后角膜图像采集系统”采集角膜数字图像，基于 MATLAB软件分割角膜瞳孔区域图像后，提取6项颜色特征指标R、G、B、H、S、V的参数值，分别建立反映各指标与PMI关系的回 归方程。筛选判定系数最高的回归方程，进行可行性验证实验。结果 6 项颜色特征指标中，R、G、B与PMI显著相关( P < 0.01或P < 0.05)，H、S、V与PMI无统计学相关( P > 0.05)；经比较发现，R与PMI相关性最高( R2＝0.935)，死后相同时间个体间及个体内R值无 统计学差异( P > 0.05)；验证实验结果表明，尸体所处环境温、湿度变化，可导致PMI推断误差范围变化。结论 采集死后角膜数 字图像，结合数字图像处理技术检测角膜瞳孔区域图像颜色变化，为利用死后角膜颜色变化推断PMI提供了一种客观、可量化 的方法。 [ABSTRACT FROM AUTHOR]

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