Reversible fragile image watermarking by fuzzy approach

A reversible fragile image watermarking recovers the original image from the watermarked image and checks the integrity and authenticity of the watermarked image. In this paper we propose a high capacity reversible fragile image watermarking scheme based on a two dimensional difference expansion (2D-DE) technique which can control the distortion of watermarked image by a fuzzy approach. We divide an input image into non-overlapping 4 × 4 blocks and watermark is embedded into the high frequency wavelet coefficients of each block. Based on the structural information of each block and by using fuzzy technique, the blocks are partitioned into three groups: smooth, texture and edge. The distortion control operations for these three groups are different from each other. We control the distortion of watermarked image based on three thresholds, defined for three groups. Experimental results show that the proposed scheme has higher capacity than conventional difference expansion (DE) methods.