Related Experiment Videos
Three dimensional visualization and comparison of impressions on fired bullets
Atsuhiko Banno1, Tomohito Masuda, Katsushi Ikeuchi
1Ikeuchi Laboratory 4-6-1, Institute of Industrial Science, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505, Japan. vanno@cvl.iis.u-tokyo.ac.jp
Forensic Science International
|March 24, 2004
Summary
Forensic science can now identify bullets using 3D geometric data of tool marks, overcoming limitations of optical methods affected by lighting. This new approach offers precise, condition-independent analysis for reliable evidence matching.
Area of Science:
- Forensic Science
- Metrology
- Computer Vision
Background:
- Current forensic identification of bullets and tool marks relies on optical devices like microscopes and CCD cameras.
- These optical methods are susceptible to variations in illumination, potentially altering the appearance of striations and impacting identification accuracy.
- Appearance-based methods lack objectivity and are influenced by external lighting conditions.
Purpose of the Study:
- To investigate the use of three-dimensional (3D) geometric data of landmark impressions on fired bullets for forensic identification.
- To develop a method for analyzing 3D surface data that is independent of lighting conditions.
- To enable objective and reliable matching of tool marks using quantifiable geometric information.
Main Methods:
- Acquisition of 3D surface data of tool marks using a confocal microscope.
- Reconstruction of virtual impressions from 3D geometric data on a PC monitor.
- Numerical matching of two surface shapes through automatic alignment and determination of corresponding points.
- Distance analysis between paired points for quantitative shape comparison.
- Visualization of shape differences for intuitive interpretation.
Main Results:
- Successful acquisition and reconstruction of 3D surface data for tool mark impressions.
- Development of an automated process for aligning and comparing 3D surface models.
- Quantitative comparison of surface shapes based on geometric data, independent of lighting.
- Visualization of shape differences, providing easily perceptive and intuitive results.
Conclusions:
- Three-dimensional geometric data offers a robust alternative to appearance-based methods for forensic identification of tool marks.
- The proposed 3D analysis method provides objective, reliable, and condition-independent identification of bullets and tool marks.
- Visualization of geometric differences enhances the interpretability and perceptibility of comparison results in forensic investigations.