Securing Digital images using Reversible Watermarking by Pixel Histogram Shifting

A new reversible watermarking Scheme is proposed .One first contribution is a histogram shifting modulation which adaptively takes care of the local specificities of the image content. By applying it to the image prediction-errors and by considering their immediate neighbourhood, the scheme proposed inserts data in textured areas where other methods fail to do so. Furthermore, this proposed scheme will use a classification process for identifying parts of the image that can be watermarked with the most suited reversible modulation. This classification is based on a reference image derived from the image itself, a prediction of it, which has the property of being invariant to the watermark insertion. In this way, the watermark embedder and extractor will remain synchronized for message extraction and image reconstruction. The proposed scheme will improve a peak signal to noise ratio (PSNR) as compared to other existing scheme.

Keywords: watermarking, PSNR, histogram