Color laser printer forensic based on misregistration analysis for offline content protection

Abstract

Media forensics can enhance and protect the reliability of multimedia content where this content is accessed, manipulated, and distributed using high quality computer devices. Color laser printer forensics is a kind of media forensics which identifies the printing source of color printed materials such as fine arts, money, and document and helps to catch a criminal. This paper presents a novel color laser printer forensic algorithm based on noisy texture analysis and support vector machine classifier that can detect which color laser printer was used to print the unknown images. In the color printer mechanism, 4 primary colors are employed for color mixing representation. The 4 primary colors are Cyan, Magenta, Yellow and Black. In the inkjet printers, each of the 4 colors is represented by color inks. On the other hand, in the color laser printers, the 4 primary colors are represented by toner particles. If color inks and color toner particles had transparent characteristic, the color mixing process is quite simple. It is made by just add some primary colors for representing some color. However, the color inks and the color toner particles do not have the transparent characteristic. The halftoning method is the solution for mixing the primary colors in color printer mechanism. For printing some color image, it is decomposed by RGB(Red, Green and Blue) color space. Actually, most of color images in the computer are represented by RGB color space. Next, they are transformed to CMYK(Cyan, Magenta, Yellow and Black) color space which is employed in color printing mechanism. After that, each color planes is sampled and generated by the halftoning method. In that process, some amount and orientation of misregistration between halftone image color planes is unavoidable due to various operations within a printing process such as mechanical paper transport, paper shrinkage, and misalignment of imagers. If there is misregistration of separations overlay, the percentage...