Using dynamic pixel value mapping method to construct visible and reversible image watermarking scheme

A reversible and visible image watermarking scheme extracts a visibly embedded binary watermark image and recovers the original cover image. This paper presents a reversible and visible image watermarking scheme that embeds visible watermarks into a part of the cover image, called the embedded region R, and embeds required binary strings into the whole image through the conventional difference-expansion method. The size of the embedded visible watermark is determined by the coefficient k; a large k value leads to a large embedded region for the visible watermark. The embedded region R is first segmented to non-overlapped k×k blocks, and each block is related to one bit of the watermark image. For those blocks that are related to the logo bits of the watermark image, these k×k blocks are adjusted by the proposed dynamic pixel value mapping method for highly visual detection. The binary bit string S, composed of the binary watermark image and LSB bits of the logo watermark bits’ corresponding k×k blocks, is embedded into the cover image using the conventional difference-expansion method. Experimental results show that the watermark is clearly embedded into the embedded region R and that the distortion of the reversible embedding is limited.