Colour Image Watermarking Algorithm Based on the Arnold Transform

G channel of the RGB color host image was divided into different bit-planes and the watermark is embedded into the lowest one. Then the binary image watermark is processed by using error correcting coding and Arnold transform before embedded. The embed position is chosen according to the secret key obtained during the course of the best scrambling degree calculation in Arnold transform, so the security of traditional LSB watermarking algorithm is improved. The watermarked image was adjusted by using Radon Transform before the watermark was extracted from it. The experimental results show that the watermarks are invisible and robust against noise and commonly used image-processing methods.