Study On Reversible Data Hiding With Fragile Watermark

In recent years with the fast development of information technology, data hiding was widely used in many aspects including secret communication, data authentication, and digital works copyright protection. However, original multimedia data will be inevitably changed with data hiding. These changes cannot be ignored in many important fields, which need the original multimedia data. For instance, changes on the digital medical image will lead to severe outcome. Therefore, it is desirable to design a new type of data hiding method-reversible data hiding, which can avoid distorting the original data and exert its benefits. This method could restore the original digital image after removing the modification brought by the hiding data.This paper focuses on new reversible data hiding method on BMP and JPEG image and methods that are combined with reversible data hiding and fragile watermark to authenticate digital image effectively.First, the fundamentals of existing reversible data hiding methods on BMP image are analyzed. Based on accomplishing many existing methods, a new method that uses integer wavelet to embed data losslessly on BMP image is proposed. The experimental result proves that this method can embed much more data than the existing methods under the same PSNR. In addition, this algorithm can also achieve high PSNR while keeping relatively high capacity.Second, a new reversible data hiding method on JPEG image is presented based on analyzing the existing two methods and the unique character of JPEG. The experimental result indicates that its capacity is higher than the latest method under the same PSNR. In addition, this method can keep certain capacity under good vision performance in different quality factors.Third, methods that combined reversible data hiding and fragile watermark to authenticate BMP and JPEG image accurately in blocks are proposed. The outcome of experiment indicates that the image still keep good vision performance after being embedded authenticated data, the changed position is detected effectively and the original data could be restored accurately under good vision quality.Finally, the shortcoming of existing method on reversible data hiding and fragile watermark is analyzed and the possible developing direction is proposed.