Optical profilometry for forensic bloodstain imaging
Brayden Valea, Amanda Orrb, Colin
Elliottc, Theresa Stotesburyd*
*Corresponding author:theresa.stotesbury@ontariotechu.ca
a Forensic Science Undergraduate Program, Ontario Tech
University, 2000 Simcoe St N, Oshawa, ON, Canada, L1G 0C5
b Environmental and Life Sciences Graduate Program,
Trent University, 1600 West Bank Drive, Peterborough, ON, Canada, K9J
0G2
c Applied Bioscience Graduate Program, Faculty of
Science, Ontario Tech University, 2000 Simcoe St N, Oshawa, ON, Canada,
L1G 0C5
d Faculty of Science, Forensic Science, Ontario Tech
University, 2000 Simcoe St N, Oshawa, ON, Canada, L1G 0C5
ORCID: AO (0000-0002-2245-8448); CE (0000-0001-5883-0291); TE
(0000-0001-6452-4389)
Data Availability Statement: Scans are available by request and
data is available through
https://gitlab.com/f4301/bloodstain-profilometry.
Funding Statement: We are thankful for the funding support to
conduct this research. This work was supported by the Natural Sciences
and Engineering Research Council of Canada (NSERC) Discovery and
Discovery Accelerator Supplement Grants (RGPIN-2020-05816) awarded to
TS. Authors CE and AO are supported through the NSERC Canada Graduate
CGS-M (MSc) and CGS-D (PhD) Scholarship programs respectively.
Conflict of Interest Disclosure: The authors have no conflicts
of interests to declare.
Acknowledgements:The authors would like to formally acknowledge Mitchell Tiessen,
Kgalalelo Rampete, Julia Harvey, Dhrumik Patel, and Laurianne Lagace,
who assisted BV with fluid property measurements throughout his
undergraduate thesis. A most special thank-you goes to Dr. Iraklii
Ebralidze, of the Ontario Tech University Materials Characterization
Facility for training BV on the optical profilometer.
Abstract:
Understanding the physical,
chemical and biological changes that occur during the drying of a
bloodstain is important in many aspects of forensic science including
bloodstain pattern analysis and time since deposition estimation. This
research assesses the use of optical profilometry to analyze changes in
the surface morphology of degrading bloodstains created using three
different volumes (4, 11, and 20 µL) up to four weeks after deposition.
We analyzed six surface characteristics, including surface average
roughness, kurtosis, skewness, maximum height, number of cracks and
pits, and height distributions from the topographical scans obtained
from bloodstains. Full and partial optical profiles were obtained to
examine long-term (minimum of 1.5 hour intervals) and short-term (5
minute intervals) changes. The majority of the changes in surface
characteristics occurred within the first 35 minutes after bloodstain
deposition, in agreement with current research in bloodstain drying.
Optical profilometry is a non-destructive and efficient method to obtain
surface profiles of bloodstains, and can be integrated easily into
additional research workflows including but not limited to time since
deposition estimation.