The Application of Infrared Chemical Imaging to the Detection and Enhancement of Latent Fingerprints: Method Optimization and Further Findings

Abstract

Fourier transform infrared (FTIR) chemical imaging allows the collection of fingerprint images from backgrounds that have traditionally posed problems for conventional fingerprint detection methods. In this work, the suitability of this technique for the imaging of fingerprints on a wider range of difficult surfaces (including polymer banknotes, various types of paper, and aluminum drink cans) has been tested. For each new surface, a systematic methodology was employed to optimize settings such as spectral resolution, number of scans, and pixel aggregation in order to reduce collection time and file-size without compromising spatial resolution and the quality of the final fingerprint image. The imaging of cyanoacrylate-fumed fingerprints on polymer banknotes has been improved, with shorter collection times for larger image areas. One-month-old fingerprints on polymer banknotes have been successfully fumed and imaged. It was also found that FTIR chemical imaging gives high quality images of cyanoacrylate-fumed fingerprints on aluminum drink cans, regardless of the printed background. Although visible and UV light sources do not yield fingerprint images of the same quality on difficult, nonporous backgrounds, in many cases they can be used to locate a fingerprint prior to higher quality imaging by the FTIR technique. Attempts to acquire FTIR images of fingerprints on paper-based porous surfaces that had been treated with established reagents such as ninhydrin were all unsuccessful due to the swamping effect of the cellulose constituents of the paper.

Effect of substrate surface topography on forensic development of latent fingerprints with iron oxide powder suspension

“…Forensic casework and research laboratory studies show that latent fingerprint development efficiency can be affected by characteristics of the deposition surfaces as well as the donors [1][2][3][4][5][6][7][8][9][10][11][12].…”

The development of a wide-field infrared spectroscopic imaging apparatus using a bolometer camera and feasibility test for forensic examination

“…Obliterated writings that cannot be revealed by conventional methods may be uncovered by using MIR spectral imaging [1,2]. In addition, MIR spectral imaging has also been shown to be an excellent technique for the detection of latent and developed fingermarks on a number of challenging surfaces [3][4][5][6][7][8][9][10][11]. Attempts have also been made to apply this technique to the analysis of automobile paint chips, in medicine, etc.…”

Advances in the development and component recognition of latent fingerprints

“…In addition, the past few years have witnessed a renewal of research interest in the possibility that a fingerprint can provide additional information about the donor than mere identification [7]. To this end, numerous methods including infrared [26] and Raman spectroscopy [27], mass spectrometry (MS) [28], and immunological techniques [29,30] have been utilized.…”