Towards substrate-independent age estimation of blood stains based on dimensionality reduction and k-nearest neighbor classification of absorbance spectroscopic data

Bergmann, Tommy; Heinke, Florian; Labudde, Dirk

doi:10.1016/j.forsciint.2017.05.023

“…Commonly analyzed biomolecules for TSD estimation models include hemoglobin (Hb) from red blood cells (RBCs) and genetic material from white blood cells (WBCs). Spectroscopic techniques, such as Raman (Premasiri et al, 2012;Doty et al, 2016Doty et al, , 2017Sun et al, 2017b;Takamura et al, 2019;Menżyk et al, 2020), infrared (Botoniic-Sehic et al, 2009;Lin et al, 2017;Zhang et al, 2017;Hassan et al, 2019), reflectance (Bremmer et al, 2011a(Bremmer et al, , 2011bLi et al, 2011;Edelman et al, 2012aEdelman et al, , 2016Sun et al, 2017a) and UV-Vis absorbance (Hanson and Ballantyne, 2010;Hanson et al, 2011;Agudelo et al, 2015;Bergmann et al, 2017Bergmann et al, , 2021Kaur et al, 2020;Stotesbury et al, 2020;Cossette et al, 2021) spectroscopies have all probed the timewise degradation of Hb. Photography (Thanakiatkrai et al, 2013;Shin et al, 2017;Choi et al, 2019) and hyperspectral imaging (Edelman et al, 2012b;Li et al, 2013;Majda et al, 2018) have measured the colour changes in blood while electron spin resonance and electrochemistry analyzed the conformational changes of the heme groups (Miki et al, 1987;Matsuoka et al, 1995;Fujita et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The crux of time: A meta-analysis of ex vivo whole blood degradation

Elliott

¹

,

Shafer²,

Stotesbury³

2022

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Estimating the time since deposition (TSD) of a bloodstain can provide important medico-legal information for crime scene investigation. Research in this area primarily investigates the degradation of either hemoglobin or genetic material over time. In this work, we present a comprehensive meta-analysis on bloodstain TSD research. Our results are interpreted from 25 quantitative studies used to probe the effect of biomolecule studied, analytical technique used, substrate porosity, environmental conditions, and blood source on TSD estimates. There was an overall strong effect of time across studies (Fisher’s Zr = 1.66, r = 0.93), and generally, we found that the type of biomolecule studied (e.g., hemoglobin, DNA) had equal effect sizes for TSD estimation. Differences in the mean TSD effect size were also observed between substrate porosity. Interestingly, the blood source does not significantly influence the magnitude of the effect sizes in TSD estimation. Despite the clear effect of time, forensically relevant prediction of bloodstain TSD remains complicated by inter-donor variability, type of substrate and environmental conditions. We recommend that future bloodstain TSD research increase sample size, include summary statistics and standardize experimental methodologies so that we can develop a quantitative understanding of the physicochemical processes involved in whole blood degradation in ex vivo conditions.

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“…Neglecting the substrate contribution, it is possible to analyze the absorption peaks of hemoglobin, such as the Soret peak (400 nm), the

and

absorption spectral bands (540 nm and 576 nm), and the change in their pattern considering the time course, once transformed into

and

[ 12 , 13 ]. These features, which would otherwise be lost, are proven to be critical in forensic investigations and analysis for blood traces recognition or blood stain age estimation [ 4 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Correction of Substrate Spectral Distortion in Hyper-Spectral Imaging by Neural Network for Blood Stain Characterization

Giulietti

¹

,

Discepolo

²

,

Castellini

³

et al. 2022

Sensors

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In the recent past, hyper-spectral imaging has found widespread application in forensic science, performing both geometric characterization of biological traces and trace classification by exploiting their spectral emission. Methods proposed in the literature for blood stain analysis have been shown to be effectively limited to collaborative surfaces. This proves to be restrictive in real-case scenarios. The problem of the substrate material and color is then still an open issue for blood stain analysis. This paper presents a novel method for blood spectra correction when contaminated by the influence of the substrate, exploiting a neural network-based approach. Blood stains hyper-spectral images deposited on 12 different substrates for 12 days at regular intervals were acquired via a hyper-spectral camera. The data collected were used to train and test the developed neural network model. Starting from the spectra of a blood stain deposited in a generic substrate, the algorithm at first recognizes whether it is blood or not, then allows to obtain the spectra that the same blood stain, at the same time, would have on a reference white substrate with a mean absolute percentage error of 1.11%. Uncertainty analysis has also been performed by comparing the ground truth reflectance spectra with the predicted ones by the neural model.

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“…Commonly targeted biomolecules in blood include hemoglobin (Hb) from red blood cells (RBCs) and genetic material from white blood cells (WBCs). Spectroscopic techniques, such as Raman 7,24-28 , infrared 8,29-31 , reflectance [32][33][34][35][36][37] and UV-Vis absorbance 9,17,[38][39][40][41][42][43] spectroscopies have all probed the timewise degradation of Hb. Photography 13,14,44 and hyperspectral imaging [45][46][47] have measured the colour changes in blood while electron spin resonance and electrochemistry analyzed the conformational changes of the heme groups [48][49][50] .…”

Section: Introductionmentioning

confidence: 99%

The crux of time: A meta-analysis of ex vivo whole blood degradation

Elliott

¹

,

Shafer

²

,

Stotesbury

³

2022

Preprint

0

View full text Add to dashboard Cite

Estimating the time since deposition (TSD) of a bloodstain can provide important medico-legal information for crime scene investigation. Research in this area primarily investigates the degradation of either hemoglobin or genetic material over time. In this work, we present a comprehensive meta-analysis on bloodstain TSD research. Our results are interpreted from 25 quantitative studies used to probe the effect of biomolecule studied, analytical technique used, substrate porosity, environmental conditions, and blood source on TSD estimates. There was an overall strong effect of time across studies (Fisher’s Zr = 1.66, r = 0.93), and generally, we found that the type of biomolecule studied (e.g., hemoglobin, DNA) had equal effect sizes for TSD estimation. Differences in the mean TSD effect size were also observed between substrate porosity. Interestingly, the blood source does not significantly influence the magnitude of the effect sizes in TSD estimation. Despite the clear effect of time, forensically relevant prediction of bloodstain TSD remains complicated by inter-donor variability, type of substrate and environmental conditions. We recommend that future bloodstain TSD research increase sample size, include summary statistics and standardize experimental methodologies so that we can develop a quantitative understanding of the physicochemical processes involved in whole blood degradation in ex vivo conditions.

show abstract

Towards substrate-independent age estimation of blood stains based on dimensionality reduction and k-nearest neighbor classification of absorbance spectroscopic data

Cited by 20 publications

References 27 publications

The crux of time: A meta-analysis of ex vivo whole blood degradation

The crux of time: A meta-analysis of ex vivo whole blood degradation

Correction of Substrate Spectral Distortion in Hyper-Spectral Imaging by Neural Network for Blood Stain Characterization

The crux of time: A meta-analysis of ex vivo whole blood degradation

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