Histogram- based reversible data hiding using block division

This paper presents improved technique for reversible data hiding. It is based on dividing the image into blocks, intensity histogram of each block is generated and shifting the histograms of each image block between its minimum and maximum frequency. Data are then inserted at the pixel level with the largest frequency to maximize data hiding capacity. The peaks (maxima) of the histograms of the image tiles are then relocated to embed the data. The gray values of some pixels are therefore modified. High capacity, high fidelity, reversibility and multiple data insertions are the key requirements of data hiding in images. It is shown how histograms of image blocks of images can be exploited to achieve these requirements. Compared with data hiding method in the whole image, this scheme can result in more capacity improvement with still better image quality, depending on the image content and also improving the levels of data hiding places.