JPEG reversible data hiding method based on optimal DCT frequency embedding

Abstract

Joint photographic experts group (JPEG) images are widely used on the Internet due to their ability to maintain good picture quality while requiring less storage space.Reversible data hiding (RDH) techniques for JPEG images enable the hiding and extraction of secret information while allowing for lossless restoration of the original image.RDH is of great significance in file management and image authentication.However, many existing RDH methods result in a significant increase in the storage space of the encoded image after embedding secret information.For methods based on discrete cosine transform (DCT) coefficient embedding, the key issue that affects the performance of reversible information hiding in JPEG images is how to select the frequency band position.A reversible information hiding method for JPEG images was proposed, based on optimal DCT frequency embedding.The entropy decoded JPEG image was divided into 8×8 non-overlapping DCT blocks.The average texture complexity of each DCT block was calculated and ordered in ascending order.Then the alternating current (AC) in adjacent DCT blocks was paired pairwise.By satisfying the capacity of the information to be embedded, the optimal AC coefficient frequency position set was obtained from the distortion cost function of the AC coefficient frequency.The secret information was embedded according to the designed two-dimensional histogram mapping strategy.Experimental results demonstrate that the proposed method can reduce the expansion of the loaded image file’s storage size compared to existing methods, while maintaining good visual quality of the cover image.

Keywords

• JPEG image;reversible data hiding;two-dimensional histogram;average texture complexity