Development of a Watermark Embedding Algorithm within Digital Images in Frequency Domain using Ant colony Algorithm

Abstract

In this paper, an algorithm of watermark embedding within digital cover images was developed, in order to guarantee the copyright of digital images. The proposed algorithm depends transform the image to frequency domain, and ant colony algorithm to determine the optimal blocks to execute the embedding process. Many factors affects the achievement of watermark requirement, the most important factors are embedding domain, embedding method, coefficient used for embedding and blocks locations where The optimal location of them, that varies depending on the nature of the image and the attacks. First, we divided the cover image into 8*8 blocks and calculating standard deviation between their pixels to detect blocks of pixels with strong edges, which is considered the best in the embedding process due to its robustness towards the attacks. Then we used DCT (Discrete cosine transform) on blocks to transfer the original cover image to frequency domain and execute the embedding process relying on the proposed algorithm in two coefficients that belong to the medium frequency of  the specific blocks from ants algorithm which provides flexibility in determined the most important blocks in terms of balancing between robust of watermark and transparency of the watermark image. The proposed algorithm provided good results in the watermark robustness and transparency in proportion to the nature of cover image towards various types of image processing.