Intellectual property right protection of image data using DCT and spread spectrum-based watermarking

For digital image, watermarking provides intellectual property right protection through embedded copyright mark. However, due to attacks using signal processing methods offers challenges in designing robust copyright techniques. This paper presents a novel method for enhancing robustness in copyright marking into mid-frequency discrete cosine transform (DCT) coefficients of an image using spread spectrum techniques. Performance evaluation of proposed algorithm has been made using bit error rate (BER) and peak signal to noise ratio (PSNR) value for different watermark size and images: Lena, Girl, and Tank images yield similar results. This algorithm is simple and does not require the original cover image for watermark recovery. A set of systematic experiments, including JPEG compression, Gaussian filtering and addition of noise are performed to prove robustness of our algorithm. Thus, it is potentially useful in robust copy-right marking for intellectual property right protection applications.