The traditional watermarking techniques based on fractal coding is generally using 0

1 sequence as the watermark. This does not implement embedding gray image as the watermark. Based on orthogonal fractal coding

a new fast watermarking technique is proposed in this article which can embed gray images. Just because the orthogonal fractal decoding is a mean-invariant iteration

the watermark can be embedded into the fractal decoding parameters directly. Experimental results show that gray image’s embedding hardly does not have any effect on the fractal decoding image. And also

this scheme is better than the traditional techniques on being robust against many attacks such as cutting

low-passing filtering

and JPEG compression.