Should We Consider Adaptivity in Moment-based Image Watermarking?

The term adaptivity is absent from the state-of-the-art moment-based image watermarking methods. A question to be answered is whether adaptive watermark insertion will guide to the enhancement of image's security (concerning a number of requirements such as robustness, imperceptibility, complexity and capacity). Initially, the term adaptivity is being unfold from different perspectives; the selection of the most qualified coefficients (considering their order and magnitude) for carrying the watermark information; the selection of the most qualified image region for hosting the watermark information; and finally the optimum calibration of the quantizer parameters for embedding the watermark information. An experimental justification of the need for adaptivity is being presented, highlighting also the classic tradeoff between imperceptibility and robustness. Furthermore, a number of solutions for each adaptivity perspective are presented along with its corresponding analysis (limitations and future work). To the best of our knowledge, the current chapter constitutes the primary attempt for highlighting/justifying the significance of adaptivity during moment-based watermarking process providing also the readers with a number of tools (adaptivity solutions) that function in gray-scale and color space. Next generation moment-based image watermarking algorithms should consider and benefit from the current adaptivity solutions regarding a high quality security result.