System and Method for Improved Forensic Analysis

Abstract

The present disclosure provides for a system and method for analyzing questioned documents. A sample document is illuminated to thereby generate a first plurality of interacted photons. The first plurality of interacted photons are detected at a first detector to thereby generate a digital image. The digital image is analyzed to thereby identify at least one region of interest of the sample document. This region of interest is illuminated to thereby generate a second plurality of interacted photons. This second plurality of interacted photons are passed through a tunable filter and detected at a second detector to thereby generate a hyperspectral image representative of the region of interest. The hyperspectral image may then be analyzed to evaluate changes to or differentiate different inks present in the sample document. Chemometric techniques such as k-means clustering, PCA, and/Or PLSDA may also be applied.

What is claimed is: 
     
         1 . A method comprising:
 (a) selecting a first location of a sample document, wherein the first location comprises at least one ink type;   (b) generating at least one hyperspectral image representative of the first location;   (c) analyzing the hyperspectral image to determine whether or not two or more ink types are distinguishable in the first location.   
     
     
         2 . The method of  claim 1  wherein in the analyzing further comprises:
 (d) if two or more inks are distinguishable in the first location, reporting a result, and 
 (e) if two or more inks are not distinguishable in the first location,
 (i) applying a first chemo metric technique to generate a processed image, and 
 (ii) analyzing the processed image to determine if two or more inks are distinguishable in the first location. 
 
 
     
     
         3 . The method of claim further comprising, if two or more inks are not distinguishable in the first location, repeating step (e) for at least one other chemometric technique. 
     
     
         4 . The method of  claim 2  wherein the first chemometric technique further comprises at least one of: principle component analysis, partial least squares discriminate analysis, cosine correlation analysis, Euclidian distance analysis, k-means clustering, multivariate curve resolution, band t. entropy method, mahalanohis distance, adaptive subspace detector, spectral mixture resolution, and combinations thereof. 
     
     
         5 . The method of  claim 3  wherein the other chemometric technique further comprises at least one of: principle component analysis, partial least squares discriminate analysis, cosine correlation analysis, Euclidian distance analysis, k-means clustering, multivariate curve resolution, band t, entropy method, mahalanobis distance, adaptive subspace detector, spectral mixture resolution, and combinations thereof. 
     
     
         6 . The method of  claim 1  wherein analyzing the hyperspectral image further comprises automatically detecting at least one of: ink pixels, background pixels, and combinations thereof. 
     
     
         7 . The method of  claim 6  wherein the first chemometric technique is applied only to ink pixels. 
     
     
         8 . The method of  claim 1  wherein the analyzing is at least semi-automated. 
     
     
         9 . The method of  claim 1  wherein selecting the first location of the sample document further comprises:
 generating a digital image representative of the sample document, and 
 analyzing the digital image to select the first location. 
 
     
     
         10 . The method of  claim 1  wherein the hyperspectral image further comprises at least one of: a visible hyperspectral image, a fluorescence hyperspectral image, an infrared hyperspectral image, a visible-near infrared hyperspectral image, and combinations thereof. 
     
     
         11 . The method of  claim 1  wherein the analyzing further comprises visual inspection by a user. 
     
     
         12 . The method of  claim 1  further comprising extracting spectral information from the hyperspectral image and evaluating at least one spectra associated with at least one ink present in the first location. 
     
     
         13 . The method of claim further comprising repeating steps (a)-(c) for at least one other location in the sample document. 
     
     
         14 . The method of  claim 2  further comprising repeating steps (d)-(e) for at least one other location in the sample document. 
     
     
         15 . The method of  claim 1  wherein generating the hyperspectral image further comprises:
 illuminating the first location to generate at least one plurality of interacted photons; 
 passing the interacted photons through a tunable filter to filter the interacted photons into a plurality of wavelength bands; and 
 detecting the filtered interacted photons to generate the hyperspectral image. 
 
     
     
         16 . The method of  claim 15  wherein the illuminating further comprises the use of at least one of:
 a UV light source, a broadband light source, and combinations thereof. 
 
     
     
         17 . The method of  claim 3  wherein the first chemometric technique and the at least one other chemometric technique are different. 
     
     
         18 . The method of  claim 3  wherein the first chemometric technique and the at least one other chemometric technique are the same. 
     
     
         19 . The method of  claim 13  wherein the first location of the sample document and the at least one other location of the sample document at least partially overlap. 
     
     
         20 . The method of  claim 13  wherein the first location of the sample document and the at least one other location of the sample document do not overlap.