Enhanced Dct Image Watermarking Scheme Based on Zonal Sampling Algorithm Applied With Sspce Contour Extraction, Ramer and Adaptive Triangle Contour Compression Methods

Abstract

This paper proposes an image watermarking scheme based on DCT transform and selected zonal sampling algorithms. The scheme used LPF and HPF transform coefficients in a certain geometric zone of the original image are retained. All the rest of the parameter is set to zero (0), quantized and transmitted where the watermark will be embedded. In order to test robustness, some attacks are performed.  However, prior to the watermark extraction process, the attacked watermarked image will be subdued into contour processing methods using Single Step Parallel Contour Extraction, Ramer and Adaptive Triangle algorithms. The proposed method for contour compression will help enhance image recognition, security and especially where time (speed) is an essential factor. The results show that the proposed watermarking method is robust and secure against various signal/image processing attacks with PSNR values of approximately 35 dB with NCC values of 0.60 and above. In addition, experimental results from contour compression indicate that the proposed Adaptive Triangle method has a high compression ratio without significant visible distortion