Zero-Watermark Method Based on Non-Uniform BTC Partition

Zero-watermarking is an effective method to better pro tect the copyright of images. This paper proposes a new ze ro-watermarking algorithm based on Non-uniform Block Tr uncation Coding (NUBTC). In the proposed scheme, the ori ginal image is divided into different rectangular grids accor ding to the non-uniform block-truncation-coding partition, a nd the feature matrix is formed by calculating number of rectangles in each 8*8 sub-area. The obtained feature matri x is further mapped to a binary watermark after Arnold s crambling, and both of them are stored as the zero water mark. Experimental results indicate that the extracted zero-watermark could keep more than 90% similarity to the un attacked zero-watermark under JPEG com pression attack a nd other various noise attacks, thus proving that the propo sed zero-watermark scheme is very robust when sufferring attacks.