Robust data hiding for images

Data hiding is the process of encoding extra information in an image by making small modifications to its pixels. To be practical, the hidden data must be perceptually invisible yet robust to common signal processing operations. This paper introduces two schemes for hiding data in images. The techniques exploit perceptual masking properties to embed the data in an invisible manner. The first method employs spatial masking and data spreading to hide information by modifying the image coefficients. The second method uses frequency masking to modify the image spectral components. By using perceptual masking, we also increase the robustness of the hidden information. Experimental results of data recovery after applying noise and JPEG coding to the hidden data are included.