Presentation is loading. Please wait.

Presentation is loading. Please wait.

New perspectives in the use of ink evidence in forensic science

Similar presentations


Presentation on theme: "New perspectives in the use of ink evidence in forensic science"— Presentation transcript:

1 New perspectives in the use of ink evidence in forensic science
Cedric Neumann, Pierre Margot  Forensic Science International  Volume 185, Issue 1, Pages (March 2009) DOI: /j.forsciint Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

2 Fig. 1 representation of the scan of the elution track of an ink sample when the elution track is simultaneously scanned at 31 different wavelengths (x-axis: migration distance in mm; y-axis: wavelengths in nm; z-axis: absorption intensity in au). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

3 Fig. 2 Presentation of the concept of the calibration process. The new coordinate system (grid) is anchored on the three ladders on each plate. The new coordinates of the other elution tracks of the plate are computed from these three ladders, the base line and the solvent front (dots) by linear interpolation. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

4 Fig. 3 Schematic description of a possible strategy. All components from each sample are identified and the respective lists of components are compared. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

5 Fig. 4 Schematic description of a second possible strategy: The presence/absence of each component of the first sample in the second sample is recorded and reciprocally. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

6 Fig. 5 Schematic description of the third strategy: the two-dimentional matrices for both inks are compared mathematically. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

7 Fig. 6 Euclidean distance (algorithm A) on dataset 5 (samples from same ink on the same. plate) Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

8 Fig. 7 Euclidean distance (algorithm A) on dataset 4 (samples from same ink on different. plates) Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

9 Fig. 8 Euclidean distance (algorithm A) on the entire dataset.
Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

10 Fig. 9 Pearson correlation (algorithm B) on the entire dataset.
Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

11 Fig. 10 ANN (algorithm D—compilation along the migration distances) on the entire dataset. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

12 Fig. 11 ANN (algorithm F—compilation along the wavelengths) on the entire dataset. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

13 Fig. 12 Comparison between the performances of the six algorithms on all samples from all datasets together. The ANN are referenced by their letter in Table 2, by the number of neurones in each layer, as well as by whether they have been trained on fresh (F) or fresh and degraded (F&D) samples. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

14 Fig. 13 Comparison between the performances of the six algorithms on the samples from dataset 9 (exposure to sun). The ANN are referenced by their letter in Table 2, by the number of neurones in each layer, as well as by whether they have been trained on fresh (F) or fresh and degraded (F&D) samples. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

15 Fig. 14 Comparison between the performances of the six algorithms, when processing only fresh ink samples (datasets 1–5). The ANN are referenced by their letter in Table 2, by the number of neurones in each layer, as well as by whether they have been trained on fresh (F) or fresh and degraded (F&D) samples. Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

16 Fig. 15 DET curves for all different conservation conditions for algorithms A (Euclidean distance). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

17 Fig. 16 DET curves for all different conservation conditions for algorithms B Pearson correlation). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

18 Fig. 17 DET curves for all different conservation conditions for algorithms C (ANN trained on fresh samples). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

19 Fig. 18 DET curves for all different conservation conditions for algorithms D (ANN trained on fresh and degraded samples). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

20 Fig. 19 DET curves for all different conservation conditions for algorithms E (ANN trained on fresh samples). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions

21 Fig. 20 DET curves for all different conservation conditions for algorithms F (ANN trained on fresh and degraded samples). Forensic Science International  , 38-50DOI: ( /j.forsciint ) Copyright © 2009 Elsevier Ireland Ltd Terms and Conditions


Download ppt "New perspectives in the use of ink evidence in forensic science"

Similar presentations


Ads by Google