Semiautomatic reconstruction of strip-shredded documents
Patrick DE SMET, Johan De Bock, Wilfried R. Philips · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
Until recently, the forensic or investigative reconstruction of shredded documents has always been dismissed as an important but unsolvable problem. Manual reassembly of the physical remnants can always be considered, but for large amounts of shreds this problem can quickly become an intangible task that requires vast amounts of time and/or personnel. In this paper we propose and discuss several image processing techniques that can be used to enable the reconstruction of strip-shredded documents stored within a database of digital images. The technical content of this paper mainly revolves around the use of feature based matching and grouping methods for classifying the initial database of shreds, and the subsequent procedure for computing more accurate pairing results for the obtained classes of shreds. Additionally, we discuss the actual reassembly of the different shreds on top of a common image canvas. We illustrate our algorithms with example matching and reconstruction results obtained for a real shred database containing various types of shredded document pages. Finally, we briefly discuss the impact of our findings on secure document management strategies and the possibilities for applying the proposed techniques within the context of forensic investigation.