Hierarchical Activities Designed for High-Resolution Visualization and Quantitative Analysis of Fingerprint Sweat Pores

Level 3 characteristics are increasingly important forfingerprintidentification, particularly when the fingerprints are problematicand lack level 2 details. In practice, no reliable visualization methodsfor level 3 features are transferred into a course for the generalpublic, forensic students, or investigators. Our group has reportedthe membrane/water technique and wet-membrane method as simple, instantaneous,high-resolution, and reproducible methods for visualizing level 3features of latent fingerprints (LFPs). Herein, we designed a simple-to-operatelaboratory course on sweat pore visualization and analysis via thetwo methods mentioned. Three modules are included, and students participatein different modular combinations according to their interests andspecialties. Module 1, consisting of a 15 min lecture on fingerprinttheory followed by a brief demonstration of visualization procedures,is designed for broad audiences ranging from primary school to collegelaboratories. In module 2, students explored the deposition forceimpact on level 3 features (for students majoring in forensic science).Module 3 customized for forensic upper-division undergraduates andpostgraduates invites them to conduct Gaussian fitting of the porearea and adjacent pore distance. After discussion, students form theirown opinions on the identifiable strengths of the above parametersin fingerprint matching. In a way, this experiment can be evolvedinto the elective course and specialized curriculum, where electivecourse containing module 1 can stimulate public interest in chemistryand specialized curriculum including modules 1-2 (or modules1-3) may guide students to extract level 3 features and understandthe role of level 3 features at a quantitative level.