Research on Identification Method of Covered Handwriting Based on Hyperspectral Imaging Technology

In criminal and civil cases, signatures, dates, numbers, and other handwritings of several important documents are deliberately covered to conceal the real information such that they cannot be used as evidence. Therefore, it is necessary to study the feasibility of hyperspectral imaging technology (approximately 450–950 nm) for rapid and non-destructive identification of covered handwriting. Black handwriting pens are mostly used such that two pens are randomly selected from 21 kinds of black handwriting pens to cover each other as samples. Simultaneously, two kinds of black handwriting pens with carbon in the ink and two kinds of black handwriting pens without carbon in the ink are selected, and the same pen is used to write and cover by itself as a sample. The experimental results show that most of the covered handwriting can be completely and clearly identified using hyperspectral imaging technology in the band of approximately 450–950 nm with the real shape and information, which has a good effect. Part of the identification effect is not good, and the details of the original handwriting are incomplete, but the original handwriting can be recognized. In addition, few parts are blurred, which cannot meet the identification requirements. However, most of the covered handwriting is difficult to develop using the traditional infrared method.