Jeanne Chen

Reversible data hiding using Delaunay triangulation and selective embedment

In this paper, we propose a reversible data hiding method based on prediction and histogram-shifting (PHS) using Delaunay triangulation and selective embedment. Because the statistical properties of the prediction errors along the embedding direction are significantly altered due to the shifting operation, the existing PHS-based methods are vulnerable to some steganalyzers. The proposed method exploits a set of key-selected referential pixels to construct a 3D Delaunay mesh to obtain the prediction errors. The presence of the altered statistical properties along the embedding direction is unrevealed because the same set of prediction errors cannot be reconstructed. A selective embedment mechanism is used to control the embedding regions in the cover image for evading the detection of the steganalyzers based on low-amplitude stego signal. The experimental results reveal that the proposed method not only provides better payload and image quality than the existing PHS-based methods, but is also robust to the detection of modern steganalyzers such as histogram analysis and SPAM.

Steganography for BTC compressed images using no distortion technique

Abstract In this paper, we proposed an improved data hiding scheme to embed secret data in the compressed bitstreams where the quality of the image is maintained even after embedment. The difference in the quantized values for each block is used to determine whether only 1 bit of secret is to be hidden for the block or to toggle bits in the bitmap to hide more bits. The scheme has a high payload and is a no distortion data hiding. Experimental tests with Lena showed that in the 2 × 2 block-sized BTC compressed bitstreams, an additional 10 488 bits were embedded and 416 bits for the 4 × 4 block-sized. The new improved scheme increases payload and is reversible.

Reversible Data Embedment for Encrypted Cartoon Images Using Unbalanced Bit Flipping

In this paper, we propose a reversible data hiding technique to improve Zhang and Hong et al.’s methods on cartoon images. Zhang and Hong et al. exploit the block complexity for data extraction and image recovery. Their methods are efficient for natural images, however, the results are unsatisfactory when applies on cartoon images consisting of large flat area. By unbalanced flipping the bits of pixel groups, the block complexity before and after flipping can be distinguished and thus the error rate can be further reduced. Experimental results show that the proposed method has lower error rate than those of Zhang and Hong et al.’s methods without degrading the image quality.

An improvement of diamond encoding using characteristic value positioning and modulus function

The diamond encoding technique controls payload and image quality by a k value. Although a small increase in k can increase payload, it also increases image distortion. In this paper, we proposed an improvement scheme to the diamond encoding technique for reducing image distortion during a k change. Another aim is to increase payload size. A square matrix conversion of the diamond matrix is used to lower the MSE values in high payload when k=3. A lower MSE reduces image distortion. In low payload, that is when k changes from 1 to 2, a one dimension matrix modulus is used to reduce image distortion. Experimental results showed that payload may be increased while image quality is not significantly reduced.

Data hiding by Exploiting Modification Direction technique using optimal pixel grouping

Zhang and Wang proposed the Exploiting Modification Direction (EMD) in 2006. The pixels in the image were grouped into n pixels per group. A pixel in each group is modified one gray scale value at most to hide a secret digit in a (2n+1)-ary notational system. In this paper, we proposed an optimized EMD method by analyzing the relationship between n and payload. The study involves using known payload on EMD to ascertain the least distortion result to begin the actual hiding process. Comparison results showed that the PSNR of optimized EMD embedding is significantly higher than OPAP and LSB by at least 3 dBs.

A New Reference Pixel Prediction for Reversible Data Hiding with Reduced Location Map

In this paper, a new reversible data hiding method based on a dual binary tree of embedding levels is proposed. Four neighborhood pixels in the upper, below, left and right of each pixel are used as reference pixels to estimate local complexity for deciding embeddable and non-embeddable pixels. The proposed method does not need to record pixels that might cause underflow, overflow or unsuitable for embedment. This can reduce the size of location map and release more space for payload. Experimental results show that the proposed method is more effective in increasing payload and improving image quality than some recently proposed methods.

A Space Increased Reversible Information Hiding Technique by Reducing Redundant Recording

This paper proposes improvements to the reversible hiding technique proposed in by Hong et al. in 2012. The proposed technique is based on the characteristics of the human visual on neighboring pixel values to obtain the average for calculating the minimum value of just noticeable difference (JND). The JND is then used to determine the suitable embedding level to decrease image distortion. Hong et al.’s method will first shift pixels that caused overflow and underflow after finding the suitable embedding level. The values of the shifted pixel will be recorded in a location map the size of an image. The binary location map was JBIG2 compressed and embedded with the secret information. In the location map, pixels not shifted were recorded as 0. Therefore, many pixels were recorded. These resulted in the compressed length to be longer which affects the payload size. Experimental results showed that our proposed method decreases the size of the location map, payload is increased but the image quality is maintained similar to Hong et al.’s method.

A Heuristic Magic Square Algorithm for Optimization of Pixel Pair Modification

Pixel pair modification (PPM) based magic squares is proposed for data hiding. The aim is to improve the drawbacks of payload versus PSNR of LSB. The traditional PPM-related methods did not consider the combination of square contents. In this paper, a heuristic magic square algorithm for PPM is proposed to select the optimal magic square combination for data hiding while the quality of the stego-image is maintained without affecting the amount of payload. Results showed that the heuristic magic algorithm can quickly recommend the suitable combination of magic squares with calculated efficiency on the range of 2% to 20%. The algorithm can enhance PPM based on magic squares and increase the efficiency of data hiding.

VoIP communication quality and flow volume preference — A SIP and Red5 example

In this modern era, communication through internet is popular. Business exchange on internet phone is thriving. However, current internet phones in the market do not guarantee voice quality. The purpose of this paper is to ascertain the effectiveness of different internet voice packet techniques towards voice quality and to select the technique that is more reliable and to realize closer to the original sound quality. Surveys were conducted Quality of Service for comparison of SIP and Red5 flow, and on voice quality acceptance level of the general public. The study concluded that: (1) while Red5 internet phone has higher transmission quality and occupying less web band, its voice quality is undesirable; (2) although SIP internet phone occupies larger band and its packets drops easily, voice quality is higher than Red5.

A secure data hiding method based on preservation of saturated pixels

Zhang and Wang in 2007 proposed an exploring the modification of embedding directions (EMD) method for which n pixels are used as an embedding unit, and a digit in based 2n+1 can be concealed by modifying a pixel value a grayscale at most. In case the overflow or underflow problems occur, EMD adds or subtracts one of the saturated pixels in the same pixel group by one and re-embeds the digit. However, if the number of saturated pixels is considerable, the modification of the saturated pixels may result in a critical vulnerability to the LSB-based steganalyzers. This paper proposes a method to leave those saturated pixels untouched and embeds only those non-saturated ones. Because no saturated pixels are modified, the stego image is insensitive to the detection by the LSB-based steganalyzers. The experimental results reveal that the proposed method is more robust to the LSB-based steganalyzers than the original EMD method when the number of saturated pixels is considerable.