Corneal-Smart Phone: A novel method to intelligently estimate postmortem interval.

Area of Science:

• Forensic Science
• Digital Image Analysis
• Ophthalmology

Background:

• Postmortem corneal opacity changes are used for estimating postmortem interval (PMI).
• Current methods lack objective and rapid quantification of corneal changes at crime scenes.
• Accurate PMI estimation is crucial in forensic investigations.

Purpose of the Study:

• To develop an intelligent system for rapid postmortem interval estimation using corneal digital images.
• To construct a data analysis model correlating corneal image features with PMI.
• To validate the accuracy and reliability of the developed system.

Main Methods:

• Developed a smartphone-based system (Corneal-Smart Phone) with a darkroom attachment for image capture.
• Extracted six color features (R, G, B, H, S, V) and four texture features (CON, COR, ASM, HOM) from segmented corneal pupil regions.
• Correlated extracted features with PMI using a data analysis model, identifying Contrast (CON) as the most significant feature.

Main Results:

• Contrast (CON) showed the highest correlation with PMI (R² = 0.983) with no significant intra/intersubject variation.
• CON values increased with higher ambient temperature and lower humidity.
• PMI prediction error was <3 hours within 36 hours postmortem, extending to 6-8 hours after 36 hours.
• Blind test samples achieved an 82% correct classification rate.

Conclusions:

• The Corneal-Smart Phone system offers a novel, objective, and rapid method for PMI estimation.
• Digital analysis of postmortem corneal images provides a reliable forensic tool.
• This technology can significantly aid forensic practitioners in time-of-death investigations.