Thai-Son Nguyen

A high payload steganographic algorithm based on edge detection

Abstract The least-significant-bit (LSB) technique is one of the commonly used steganographic algorithms in the spatial domain. In most existing schemes, they didn’t carefully analyze the relationship between the image content itself. Hence, the smooth areas in the cover image will inevitably be contaminated after hiding even at a low embedding rate, thereby leading to poor visual quality and low security. In recent years, diverse steganography methods using edge detection have been proposed. However, their schemes employ certain pixels in the cover image for the sake of storing edge information, resulting in significant embedding distortion and low payload. In this study, a novel steganography approach based on the combination of LSB substitution mechanism and edge detection is proposed. To avoid the excavation of human visual system (HVS) when more secret bits are embedded into pixels, we classify the cover pixels into edge areas and non-edge areas. Then, pixels that belong to the edge area are used to carry more secret bits. In addition, to further increase the payload as well as preserve good image quality, we adopt a skillful way that the edge information is determined by most significant bits (MSBs) of the cover image so that it does not need to be stored. In the extraction phase, the same edge information is obtained. Therefore, the secret data can be correctly extracted without confusion. The experimental results demonstrate that our scheme achieves a much higher payload and better visual quality than those of state-of-the-art schemes.

Image Watermarking Scheme Based on Scale-Invariant Feature Transform

In this paper, a robust watermarking scheme is proposed that uses the scale-invariant feature transform (SIFT) algorithm in the discrete wavelet transform (DWT) domain. First, the SIFT feature areas are extracted from the original image. Then, one level DWT is applied on the selected SIFT feature areas. The watermark is embedded by modifying the fractional portion of the horizontal or vertical, high-frequency DWT coefficients. In the watermark extracting phase, the embedded watermark can be directly extracted from the watermarked image without requiring the original cover image. The experimental results showed that the proposed scheme obtains the robustness to both signal processing and geometric attacks. Also, the proposed scheme is superior to some previous schemes in terms of watermark robustness and the visual quality of the watermarked image.

Adaptive image sharing based on the quadri-directional search strategy with meaningful shadows

Image sharing is a technique that is used to protect the security of a secret image by placing it into shadows. In this paper, we propose a new image sharing scheme based on the quadri-directional search strategy with meaningful shadows. In the proposed scheme, a modulus reference table is generated and used to share different sizes of the secret image. By doing so, the proposed scheme can preserve the high image quality of the shadows. In the secret image recovery phase, we can reconstruct the secret and cover images losslessly. Our experimental results demonstrated that the proposed scheme can share different sizes of secret images while maintaining good image quality of the shadows. Compared with some previous image sharing schemes, the proposed scheme provides better performance in both embedding capacity and image quality. The proposed scheme also achieves higher embedding capacity than some previous reversible data hiding schemes while keeping small distortion in the shadows.

High Embedding Capacity Data Hiding Algorithm for H.264/AVC Video Sequences without Intraframe Distortion Drift

Data hiding is a technique that allows secret data to be delivered securely by embedding the data into cover digital media. In this paper, we propose a new data hiding algorithm for H.264/advanced video coding (AVC) of video sequences with high embedding capacity. In the proposed scheme, to embed secret data into the quantized discrete cosine transform (QDCT) coefficients of frames without any intraframe distortion drift, some embeddable coefficient pairs are selected in each block, and they are divided into two different groups, i.e., the embedding group and the averting group. The embedding group is used to carry the secret data, and the averting group is used to prevent distortion drift in the adjacent blocks. The experimental results show that the proposed scheme can avoid intraframe distortion drift and guarantee low distortion of video sequences. In addition, the proposed scheme provides enhanced embedding capacity compared to previous schemes. Moreover, the embedded secret data can be extracted completely without the requirement of the original secret data.

Effective reversible image steganography based on rhombus prediction and local complexity

Reversible image steganography attracts much attention of researchers since such technique has ability to reconstruct the original version of the host image losslessly after image steganography. In this paper, we propose a new reversible image steganography based on rhombus prediction and local complexity. To maintain good quality of stego images and to achieve high accuracy of tamper detection, the local complexity of each pixel is first evaluated, then, the prediction error is calculated by using rhombus prediction for embedding the authentication code. Experimental results demonstrated that the proposed scheme has ability to recover the original version of the host images. In addition, the proposed scheme obtains better performance than previous schemes in terms of tamper detection and image quality.

A novel reversible data hiding scheme with two-dimensional histogram shifting mechanism

In this paper, we propose a novel reversible data hiding technique based on two-dimensional histogram shifting for quantized discrete cosine transformation coefficients (QDCT). In the proposed scheme, a two-dimensional histogram is constructed by QDCT coefficients blocks with the size of 8u2009×u20098 of the left image and the right image. Once most of the QDCT coefficients are located at the top-right corner of the two-dimensional histogram, the QDCT coefficients are selected for embedding data to achieve high embedding capacity. In the embedding procedure, the three main steps, i.e., expanding, shifting, and embedding, are only used for QDCT coefficients in this corner not only to gain embedding capacity, but also to maintain good visual quality of stego images. The experimental results demonstrated that the proposed scheme is superior to the previous schemes in terms of embedding capacity and image quality.

A reversible data hiding scheme for image interpolation based on reference matrix

Data hiding is a security technique used to conceal secret information into digital media. Reversible data hiding can guarantee that the secret message can be extracted correctly and that the cover image can be reconstructed exactly. In this paper, we presented our design of a new reversible data hiding scheme, which is based on Sudoku reference matrix and can enhance the performance of some reversible data hiding schemes for image interpolation. This allows embedding more secret bits into a pair of pixels while maintaining the small distortion of the stego-image. Our experimental results indicate that the proposed scheme had a higher embedding capacity than some other previous schemes. In addition, the proposed scheme maintains a better visual quality of the stego-image than some existing schemes.

A robust hybrid watermarking scheme based on DCT and SVD for copyright protection of stereo images

Digital watermarking is a technique that is widely used to protect rightful ownership of digital images. In this paper, we proposed a hybrid watermarking scheme for stereo images copyright protection. According to the property of stereo images, similar block pairs are located by using a certain key. Then, each block pair is transformed into DCT domain and DCT coefficients are extracted from the anti-diagonal of such block pair to form matrix A. Watermark image is embedded into singular values by applying SVD transformation on the matrix A. The experimental results showed that the proposed scheme can resist to different types of image attacks, such as salt and pepper, noise, and gaussian (density up to 5%). In addition the bit correlation ratio of extracted watermarked images is obtained up to 95%.