Inter- and intra-individual variation in earprints

Meijerman, L. (2006)

Doctoral Thesis

The feasibility of earprint individualization depends upon the amount of variation in prints of different ears, but also upon that in prints of a single ear. In order to determine the limits to intra-individual variation, we need to explore its potential causes. As the amount of force that is applied by the ear to the listening surface influences the appearance of the earprint, we investigated factors potentially affecting this force, such as the level and frequency of a target sound, and the level of ambient noise. We also investigated whether presence or absence of a target sound was of influence. Additionally, we explored if the duration of listening, and whether the ear had been recently cleaned or not, affected the appearance of an earprint. To evaluate the extent to which features may vary with passing time, we further attempted to determine the rate of growth of the external ear during adult life. As a next step, we then compared realistic intra-individual variation in earprints with a very small degree of inter-individual variation, i.e., that in prints of identical twins. To do so, we explored a method to fully automatically analyze prints. To our knowledge, this was the first time that any method capable of fully automated earprint comparisons has been described.

• Earprint
• Forensic science
• Individualization
• Ear identification
• Classification

• All authors: Meijerman, L.
• Supervisor: Maat, G.J.R.
• Qualification: Doctor (dr.)
• Awarding Institution: Faculty of Humanities, Leiden University
• Date: 2006-02-15
• Publisher: Leiden: Barge's Anthropologica
• ISBN (print): 9789080645691
• Court: LEI Universiteit Leiden