Identification of bullets fired from air guns using machine and deep learning methods

Forensic Science International, Journal Year: 2023, Volume and Issue: 349, P. 111734 - 111734

Published: May 19, 2023

Ballistics (the linkage of bullets and cartridge cases to weapons) is a common type evidence encountered in criminal around the world. The interest lies determining whether two were fired using same firearm. This paper proposes an automated method classify from surface topography Land Engraved Area (LEA) images pellets machine deep learning methods. curvature was removed loess fit features extracted Empirical Mode Decomposition (EMD) followed by various entropy measures. informative identified minimum Redundancy Maximum Relevance (mRMR), finally classification performed Support Vector Machines (SVM), Decision Tree (DT) Random Forest (RF) classifiers. results revealed good predictive performance. In addition, model DenseNet121 used LEA images. provided higher performance than SVM, DT RF Moreover, Grad-CAM technique visualise discriminative regions These suggest that proposed can be expedite projectiles firearms assist ballistic examinations. this work, compared air both rifles high velocity pistol. Air guns collect data because they more accessible other could as proxy, delivering comparable LEAs. methods developed here proof-of-concept are easily expandable bullet case identification any weapon.

Language: Английский

---

Approach to breech face impression comparison based on the robust estimation of a correspondence function

Forensic Science International, Journal Year: 2022, Volume and Issue: 333, P. 111229 - 111229

Published: Feb. 11, 2022

Language: Английский

---

Bullet signature measurement with chromatic confocal sensor

Applied Optics, Journal Year: 2020, Volume and Issue: 59(22), P. 6594 - 6594

Published: July 2, 2020

A new, non-contact, three-dimensional (3D) bullet signature measuring system based on a chromatic confocal sensor is developed. The composed of precision rotary table and sensor. measurement uncertainty the less than 1 µm. When surface topography object, acquires wavelength information reflected from object instead intensity information. This advantage very suitable to measurements. works in point mode can acquire data continuously with high speed. One round section body takes minute.

Language: Английский

---

Similarity evaluation of 3D surface topography measurements

Measurement Science and Technology, Journal Year: 2021, Volume and Issue: 32(12), P. 125003 - 125003

Published: Aug. 6, 2021

With the recent advances in three-dimensional (3D) optical scanning technologies, 3D surface topography measurement plays an increasingly important role many fields, such as product quality inspection additive manufacturing (AM), gauge capability analysis, and firearm identification forensic science. In this paper, we establish a thorough flexible new framework of data comparison that generates scaled similarity score for pair measurements, distinguishes matched non-matched pairs based on score. If two measurements are portraying same surface, they defined pair. not, This evaluation can be very useful comparing systems, quantifying different sources variation process, monitoring stability uniformity thus has great potential to improve assurance cycle AM processes long run. We illustrate statistically evaluate binary classification performance measured from manufactured parts large scale. also examine how repeated operators affect performance. compare our work with baseline method using roughness average parameter Ra. The results show methodology distinguish high accuracy, it outperforms greatly. serves benchmark generalized used other fields where critical role.

Language: Английский

---

The validation of 3D virtual comparison microscopy (VCM) in the comparison of expended cartridge cases

Journal of Forensic Sciences, Journal Year: 2021, Volume and Issue: 67(2), P. 516 - 523

Published: Nov. 22, 2021

In this study, the Cadre TopMatch-3D scanner and associated virtual comparison software was evaluated to determine whether technique is a valid reliable method of conducting cartridge component comparisons. That is, if microscopy (VCM) produces results at least equivalent those generated through traditional light (LCM), would be deemed for use in an operational setting. Particular emphasis placed on capability render same source conclusions. Of 40 true identifications available each examiner, corresponding total 520 comparisons, positive were made more frequently using VCM as compared LCM where inconclusive conclusions provided higher rate. produced sensitivity (88.41%) specificity (13.64%) rate than LCM, 80.08% 12.50%, respectively. Based findings considered together with benefits that offers name efficiency, it became apparent Cadre's 3D scanning microscope its tested study appropriate comparisons expended cases can implemented into routine casework purpose.

Language: Английский

---