The NAS Report Effect: Could Hyperspectral Imaging Help Shape the Forensic Science Landscape?
By Sara Nedley, Forensic Scientist
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| Hyperspectral imaging of blood, lotion, and lipstick on black 100% cotton material |
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| Spectra of mutiple stains showing spectrally-based differentiation. |
It is hard to imagine a time when drug chemists didn’t rely on GC-MS to help identify illicit drugs. If the time and effort had not been devoted to research the benefits it could bring to forensics, it is possible that many of today’s drug cases would remain unsolved. When validated, new technologies can make marked improvements and advancements to the analytical capabilities available to the forensic science community.
In 2009, the National Academy of Sciences (NAS) released a comprehensive study of forensic science that examined many things, including current practices, the need for more standardized processes, as well as the lack of funding for research within private labs and universities. One of its key recommendations is for the development of “new technical methods” or “in-depth grounding for advances developed in forensic science.” For many reasons, hyperspectral imaging (HSI), an underutilized tool in forensics investigations, could help address some of these issues.
Further research into HSI’s capabilities will allow for validation of its high sensitivity to chemical differences. In addition, HSI has the potential to reduce the human bias in final conclusions, while providing examiners with a faster means for obtaining quantitative data with minimal subjective analysis. HSI techniques provide a more objective analysis through the chemical differences observed by using the inherent spectral data to produce quantitative values, making it a well-suited tool for casework.
By combining digital imaging with spectroscopy, HSI collects images at various wavelengths to provide objective data through visual and chemical information. By thinking of color as a continuous combination of different wavelengths (black being the absorbance of all colors and white the reflectance of all colors), one can begin to understand the power of HSI. When every reflected color, or wavelength, is recombined, the final color can be seen; therefore, using a more sensitive technology to examine discrete wavelengths can provide insight into the chemistry of an object. Through the combination of powerful imaging components, such as a quantum efficient NIR camera and liquid crystal tunable filters (LCTFs), HSI provides forensic scientists access to a highly accurate selection of wavelengths, a narrower band pass, and a sensitive detector. Both the CONDORTM Hyperspectral Imaging System and the HSI ExaminerTM 100 QD can provide HSI datasets within the visible and shortwave near-infrared (NIR) regions of the electromagnetic spectrum by collecting data from 400-1100nm. Obtaining a more “discrete” color of a sample can be used to perform a variety of forensic examinations, such as locating ink differences, enhancing images of fingerprints that have been chemically processed, and creating contrast between body fluid stains and dark substrates.
Recognizing that HSI has a lot to offer to the forensics community, ChemImage will continue to pursue relationships that present valuable research about HSI instrumentation and its applications. For example, universities provide unique opportunities to form collaborations to study the use of this technology for image enhancement, sample characterization and chemical differentiation. In addition, the research being conducted will help validate the effectiveness of HSI on a wide range of evidence types, including latent fingerprints, bloodstains and questioned documents. By developing such relationships, ChemImage intends to take part in the effort to create more research-based forensic programs that will help to recruit top-notch scientists by offering opportunities to learn about cutting-edge technology. For similar reasons, our continued partnership with forensic labs throughout both the United States and international communities is also important to the advancement of HSI applications, as these groups are instrumental in the production of research and validated methods for casework. ChemImage technology has been made available to forensic scientists for research endeavors, and collaborative efforts have been made to further refine the training of questioned document examiners by conducting in-depth studies on their variability as based on interactions with new technology.
The NAS report has certainly given us, as forensic scientists and members of the scientific community, a lot to think about. ChemImage intends to continue its research and partnership opportunities with universities and scientists in the years to come. Our ultimate goal is to be a part of the advancement of forensics practices, providing HSI solutions for the betterment of the forensic science community.
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