Ballistics Imaging System for Spent Cartridge Feature Extraction
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Solution Overview
Problem
Current systems for imaging and analyzing spent firearm cartridges are inefficient due to high costs, slow response times, and inaccuracies, limiting their effectiveness in linking cartridges to specific firearms in crime scene investigations.
Innovation Solution
A ballistics imaging system captures high-definition images of spent cartridges under different illumination conditions, extracts features indicative of firing pin impact, and compares these features to determine the likelihood that cartridges were fired from the same firearm, using a trained image feature filter to reject noise features and simplify visual comparison.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual analysis by human specialists is used, then accuracy in linking cartridges to firearms is improved, but productivity and response time deteriorate
Solution Approach 1:
The patent replaces manual visual inspection and comparison by human specialists with an automated digital imaging and analysis system. The system captures high-resolution images of cartridge bases and primer faces, then uses computer algorithms to extract and compare feature patterns, substituting human cognitive analysis with automated image processing while maintaining or improving accuracy.
Solution Approach 2:
The patent creates digital copies (images) of the physical cartridge features instead of requiring direct physical examination. By capturing high-resolution images of the cartridge base and primer face, the system allows for repeated analysis, comparison, and archiving without handling the original evidence, thereby improving both accuracy through enhanced visualization and productivity through automated processing.
2Measurement precision
If traditional imaging systems are used, then device complexity is reduced, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent segments the imaging system into specialized functional modules: a cartridge holder for precise positioning, multiple illumination devices for different lighting conditions, and a digital imaging device for capture. This segmentation allows each component to be optimized for its specific function, improving overall measurement precision while managing complexity through modular design.
Solution Approach 2:
The patent applies local quality by providing different illumination conditions at different locations around the cartridge. Multiple illumination devices are positioned to provide varied lighting angles and intensities, which enhances the visibility of specific feature patterns on the cartridge base and primer face, thereby improving measurement precision for different types of markings.
3Measurement precision
If multiple illumination devices are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements universality by designing illumination devices that can serve multiple functions. The same illumination system is used to capture images of both the cartridge base and primer face under different lighting conditions, maximizing the utility of each device while improving feature detection accuracy across different surface areas.
Data Source
AI summary
Methods and systems for collecting high definition images of spent firearm cartridges under different illumination conditions described herein. Features indicative of firing pin impact with each spent firearm cartridge are extracted and compared to features extracted from different spent firearm cartridges. The likelihood that the cartridges were fired from the same firearm is determined based on the differences between the extracted features. A cartridge fixture locates a spent firearm cartridge inside an imaging chamber illuminated by different combinations of illumination devices located in different locations with respect to the spent firearm cartridge. Collected images are filtered by a trained image feature filter to extract features indicative of a firing pin strike. Features extracted from different spent firearm cartridges are compared to determine the likelihood that the spent firearm cartridges were fired from the same firearm based on one or more error metrics characterizing feature differences.