#STEGANOGRAPHY OUTGUESS HOW TO#
In this paper, based on the philosophy behind the JPEG encoder and the statistical properties of discrete cosine transform (DCT) coefficients, we present some basic insights into how to select quantized DCT coefficients for RDH. Furthermore, along with the embedding capacity and fidelity (visual quality), which have to be considered for uncompressed images, the storage size of the marked JPEG file should be considered. However, RDH in JPEG images is considerably more difficult than that in uncompressed images because there is less information redundancy in JPEG images than that in uncompressed images, and any modification in the compressed domain may introduce more distortion in the host image.
#STEGANOGRAPHY OUTGUESS ARCHIVE#
Therefore, reversible data hiding (RDH) in JPEG images is important and useful for many applications such as archive management and image authentication. Compared to the current state-of-the-art method, experimental results show that the proposed method has higher peak signal to noise ratio (PSNR) and smaller file size.Īmong various digital image formats used in daily life, the Joint Photographic Experts Group (JPEG) is the most popular. Finally, AC coefficients valued +1 and −1 are used for embedding, and the remaining non-zero AC coefficients are shifted to the left or right directions according to their sign. In order to further reduce the distortion, positions of AC coefficients are selected carefully. According to the number of zero AC coefficients, block ordering is used to embed data first in the blocks causing less distortion.
The proposed scheme embeds data using the histogram shifting (HS) method. In this paper, a data hiding method in JPEG image using a new coefficient selection technique is proposed. Although embedding data in JPEG image degrades visual quality and increases file size, it is proven to be useful for data communication and image authentication. Recently, reversible data hiding (RDH) techniques for JPEG images have become more extensively used to combine image and authentication information conveniently into one file.
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