Improved Area of Origin Estimation for Bloodstain Pattern Analysis Using 3D Scanning

Area of Science:

• Forensic Science
• Crime Scene Investigation

Background:

• Bloodstain Pattern Analysis (BPA) is crucial for crime scene reconstruction, particularly estimating the area of origin for impact patterns.
• Traditional methods rely on manual measurements and trigonometric calculations, which can present logistical and practical challenges.

Purpose of the Study:

• To evaluate the accuracy of 3D scanning technology (FARO Focus 3D scanner and FARO Zone 3D software) for estimating the area of origin in BPA.
• To compare the accuracy of 3D scanning methods against traditional manual trigonometric calculations.

Main Methods:

• Eight bloodstain impact patterns were created and analyzed using both manual trigonometric calculations and the FARO 3D scanning system.
• Paired analysis was performed to estimate the areas of origin for each pattern using both methods.

Main Results:

• FARO 3D scanning generally yielded more accurate area of origin estimates compared to the manual method.
• FARO-derived height estimates were closer to the true origin height.
• Both methods showed underestimation for origins further than 150mm from the wall and overestimation for closer origins, with underestimation increasing with distance.

Conclusions:

• The FARO 3D scanning system demonstrates improved accuracy for BPA area of origin estimation, supporting its operational implementation.
• 3D scanning offers practical benefits and provides reliable documentation for BPA reconstruction, aiding technical review and court presentation.