Improvement of the watermark detector performance using image enhancement filters

In this paper we consider the influence of some image processing techniques on the watermark detection rate. Even today´s state of the art watermarking methods are still very sensitive to complex degradation attacks such are JPEG compression, or print-scan process, so the detection rate of a watermark method decreases considerably after such attacks on a watermarked image. To improve the detection rate we reduce the degradation of the image by using unsharp, Laplacian or deconvolution filter. For the experiment dataset of 1000 images were watermarked and then compressed or printed and scanned. Degraded images were enhanced using unsharp, Laplacian and blind deconvolution filter. The watermark detection rate before and after enhancement was measured and compared. The results show that the enhancement filtering improves the watermark detection rate for almost 10 % for print scan attack and 8 % for JPEG compression.