DWT and DCT embedded watermarking using chaos theory
Lifford McLauchlan, Mehrübe Mehrübeoğlu · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2010
In this research, a new combination discrete cosine transform (DCT) and discrete wavelet transform (DWT) based watermarking system is studied. The first embedded watermark is encrypted using a chaos function, specifically the Lorenz function, based key to further conceal the data. A chaos based embedded watermark method in the DCT domain with blind watermark identification is developed and tested. Next the system is modified to utilize a second watermark embedding and identification/detection process. The second uses a pseudo random number generated (PRNG) watermark that is developed with a function of a Lorenz attractor data point as the seed state for the PRNG watermark in the detection process in the DWT domain. The efficacy of the DCT based technique, DWT based method as well as the combined DCT and DWT method is then compared to a previous techniques such as a NN based DWT based watermark embedding and identification. The three studied methods are subjected to a subset of the Checkmark attacks. Results for projection, shearing, warping, linear distortions, and Wiener filtering attacks are shown for the DWT embedded case.