Fast Fourier Transformation (FFT) for Paper Image Transmission as a Tool for Identification and Differentiation— Method Validation

The aim of this paper is to validate the paper differentiation method using Fast Fourier Transform (FFT). This method allows for visualization of a specific mesh pattern left by the production line machines during paper manufacturing. With this method it is possible to determine whether two compared sheets originate from the same source (the manufacturer), or not (from different batches of the same product or from different manufacturers). During the validation process, which aimed to confirm the method’s effectiveness and identify its limitations, a total of over 2500 comparisons were made of FFT paper samples. The samples were obtained from sheets of paper from the same manufacturer, as well as from different sources. Two algorithms were used for obtaining and comparing FFTs during the research. The obtained results indicated the high efficiency of the Fast Fourier Transform used, in both confirming and refuting the common origin of the compared sheets of paper. Document examination, paper comparison, Fast Fourier Transform (FFT)