Lossless Information Hiding in Images

3.2. Overview of Transform-Based Information Hiding

In general, transform-based information hiding algorithms are based on spectrum spread. Among various information hiding algorithms, transform domain–based algorithms are the most frequently used information-embedding algorithms. Compared with the spatial domain, transform domain is more complex, but it is robust, even if a lot of payload is embedded, the visual effect is still very good. Now a widely accepted view is that secret information should be embedded in the middle-frequency coefficients of the transform domain of the host image. This is because the high-frequency part has little effect on the quality of the original image, whereas the low-frequency part can achieve good robustness (after ...