On Periodic Properties of Interpolation and Their Application To Image Authentication

In our society digital images are a powerful and widely used communication medium. They have an important impact on our life. In recent years, due to the advent of high-performance consumer hardware and improved human computer interfaces, it has become relatively easy to create fake images. Typically, to create high quality and consistent forgeries, several types of tampering techniques are employed simultaneously. One of the most often used techniques is resampling (especially when two or more images are spliced together). Generally, resampling is based on an interpolation procedure. Typically, this procedure brings into the signal specific statistical changes. In this work we analyze and analytically describe specific periodic properties presence in interpolated signals and their derivatives. Furthermore, we propose an efficient and blind method to automatically detect the traces of geometric transformations in images and their portions. The results of the proposed method are demonstrated on several examples.