Block-based semi-reversible data hiding without overhead information

The current paper introduces a novel method for inserting data in a grayscale image without the need to include any overhead information in order to pinpoint the embedding positions or any other alteration of gray values. The method is semi-reversible in the sense that the hidden data are correctly extracted, whereas the original image is not necessarily restored. This is a realistic scenario for steganography purposes, where the important information is the hidded data and not the cover image. The method involves calculation of image block histograms. Based on the form of its histogram, a block is either selected or not for data hiding. The method is tested with many commonly used images and compared to a state of the art technique. Its performance is superior, in terms of capacity, to this method for quite similar distortion levels.