Affine Resilient Image Watermarking Based on Trace Transform

In digital image watermark applications, geometric affine transform attacks (including rotation, scaling, change of aspect ratio, translation, shearing etc) can prevent detection of watermarks. In order to solve this problem, we propose an affine resilient watermark algorithm, which uses a trace transform to normalize the image before watermark embedding and detection. Because the normalization is invariant to affine transforms, the watermark vector, which is embedded in the normalized image, is invariant to affine transforms too. What's more, the original host image is not required in watermark detection. Experimental results verify that the false positive rate is very low, and the proposed watermark algorithm is resistant to affine transforms, cropping, noising, JPEG and other image processing attacks.