A new quaternion color image watermarking algorithm

A new quaternion color image watermarking algorithm is presented. Firstly, mathematical background is introduced. Then the algorithm itself is described in detail, followed by results of experiments performed to date. At the end, conclusions are drawn and areas of possible further research are indicated. The algorithm is capable of embedding an arbitrary size binary watermark in a color image of any size. Watermarking is peformed in Quaternion Fourier Transform domain. A block of the transform pixels is assigned to every pixel (bit) of the watermark. If the logical value of the block is 1, the quaternion modulus of every pixel in the block is modified. The watermark detection scheme uses the average value taken over the QFT blocks in order to increase the algorithm´s robustness.