A novel pixel scoring method for watermarking of binary images

In order to embed data into binary images, some pixels need to be modified. Modification of these pixels will cause visual distortion. This paper proposes a novel approach to measure the distortions introduced by modifying individual pixels in binary images and the approach can be used as part of a watermark embedding process. The distortion scores of pixels are determined by the occurrence frequencies of 3×3 patterns in original binary image. Experiments results show that the proposed method matches well to human visual perception and it can be more widely applied in various types of binary images such as text images, drawings, handwritten signature, and even in halftone images.