An objective inter-comparison of trash mark constellations generated by manual and automated detection methods

Area of Science:

• Forensic Science
• Document Examination
• Image Analysis

Background:

• Trash marks on documents are unintentional markings from office machines.
• Used for source attribution in forensic document examination.
• Current methods lack empirical testing and rely on subjective analysis.

Purpose of the Study:

• To empirically test the theory that unique trash mark constellations distinguish photocopiers.
• To provide objective data for trash mark analysis in forensic science.
• To validate the use of trash marks for source attribution.

Main Methods:

• Generated objective trash mark location and size data from 50 photocopiers.
• Employed both traditional and novel automated methods for data collection.
• Utilized a variant of the Hausdorff distance algorithm for quantitative comparison of trash mark patterns.

Main Results:

• Each photocopier exhibited objectively different trash mark constellations.
• Quantitative analysis revealed distinct differences between machine patterns.
• The study successfully supported the foundational hypothesis of trash mark uniqueness.

Conclusions:

• Objective data analysis supports the uniqueness of trash mark constellations among photocopiers.
• This provides a scientifically validated basis for using trash marks in forensic document examination.
• The findings enhance the reliability of source attribution for photocopied documents.