Data Hiding in Halftone Images using Error Diffusion Halftoning with Adaptive Thresholding

Halftoning is the process of representing a gray-level image with a binary image. Data hiding is the technique of embedding data in an image without affecting its perceptual quality. DHSED is a watermarking algorithm to embed hidden binary visual patterns in two error diffused halftone images such that the hidden patterns can be visually inspected when the images are overlaid. A drawback of the DHSED method is that if the image has large areas of the same grey-level, hiding data causes some edge effects which may reveal the hidden data. In this paper we propose an improvement to the DHSED which fairly reduces the edge effects