Akademik Veri Yönetim Sistemi
ELECTRONICS (Basel), cilt.11, sa.23, ss.1-17, 2022 (SCI-Expanded)
Despite the huge advances in digital communications in the last decade, physical documents
are still the most common media for information transfer, especially in the official context. However,
the readily available document processing devices and techniques (printers, scanners, etc.) facilitate
the illegal manipulation or imitation of original documents by forgers. Therefore, verification of
the authenticity and detection of forgery is of paramount importance to all agencies receiving
printed documents. We suggest an unsupervised forgery detection framework that can distinguish
whether a document is forged based on the spectroscopy of the document’s ink. The spectra of
the tested documents inks (original and questioned) were obtained using laser-induced breakdown
spectroscopy (LIBS) technology. Then, a correlation matrix of the spectra was calculated for both
the original and questioned documents together, which were then transformed into an adjacency
matrix aiming at converting it into a weighted network under the concept of graph theory. Clustering
algorithms were then applied to the network to determine the number of clusters. The proposed
approach was tested under a variety of scenarios and different types of printers (e.g., inkjet, laser, and
photocopiers) as well as different kinds of papers. The findings show that the proposed approach
provided a high rate of accuracy in identifying forged documents and a high detection speed. It also
provides a visual output that is easily interpretable to the non-expert, which provides great flexibility
for real-world application.