Image Hatching for Visual Cryptography

Abstract

Image hatching (or non-photorealistic line-art) is a technique widely applied in the printing or engraving of currency. Diverse styles of brush strokes have previously been adopted for different areas of an image to create textures and shading. Because there is no continuous tone within these types of images, we propose a multi-level scheme, which uses different textures based on a threshold level. These textures are then applied to the different levels and are then combined to build up the final image. We propose a technique by which one can hide a secret using visual cryptography (VC) within the hatched images. Visual cryptography provides a very powerful means by which one secret can be distributed into two or more pieces known as shares. When the shares are superimposed exactly together, the original secret can be discovered without computer participation.