Acceptable Level Of Imperceptibility Research Articles

Covert communications through mobile voice channels

The rapid development and growth of cellular mobile networks in recent years has made voice channels widely available almost everywhere. On the other hand, voice dedicated channels possess properties that make them ideal options for high priority real-time secure communications. Beside these realities, information embedding has gained remarkable attention in recent years due to its potential application in multimedia security. In this regard, this study aims to propose an efficient scheme for data hiding to show the feasibility of exploiting these channels for covert communications. To this end, the authors propose new suboptimal but practical schemes based on additive and multiplicative spread spectrum methods. The analytical evaluations of the proposed techniques along with simulation results show proper efficiency of these schemes. Moreover, it is shown that the proposed scheme based on the M-ary bi-orthogonal general maximum likelihood and M-ary bi-orthogonal generalised embedding of multiplicative watermarks techniques outperform the other proposed schemes in this study. Experimental evaluation confirms that the proposed data hiding scheme benefits from an acceptable level of imperceptibility. Finally, the authors propose a security block which considerably increases the robustness of proposed structures against histogram-based steganalysis.

Data Hiding approach based on Eight-Queens Problem and Pixel Mapping Method

A new steganographic algorithm is presented using pixel mapping method based on eight queens and number of ones in pixel intensity value. In our method, we are sequentially selecting 81 pixel blocks to embed message bit. The method works with randomizing the bit selection in the 81 pixel block using eight queens’ solutions. This approach finds relationship between secret message and cover image according to the pixel mapping table. In this paper, we have presented a secure image steganography technique with acceptable levels of imperceptibility and distortion in the cover image. In presenting algorithm, security is considered by the randomize selection of eight queen’s solutions based on a seed value. The presented algorithm not only provides high level security, but also produces high capacity and good imperceptibility. The algorithm has been tested with different image file formats like BMP, TIFF and PNG.

Steganography Based on Integer Wavelet Transform and Bicubic Interpolation

Steganography is the art and science of hiding information in unremarkable cover media so as not to observe any suspicion. It is an application under information security field, being classified under information security, Steganography will be characterized by having set of measures that rely on strengths and counter attacks that are caused by weaknesses and vulnerabilities. The aim of this paper is to propose a modified high capacity image steganography technique that depends on integer wavelet transform with acceptable levels of imperceptibility and distortion in the cover image as a medium file and high levels of security. Bicubic interpolation causes overshoot, which increases acutance (apparent sharpness). The Bicubic algorithm is frequently used for scaling images and video for display. The algorithm preserves fine details of the image better than the common bilinear algorithm.

Analysis of P-QRS-T Components Modified by Blind Watermarking Technique Within the Electrocardiogram Signal for Authentication in Wireless Telecardiology Using DWT

Presently considerable amount of work has been done in tele-monitoring which involves the transmission of bio-signals and medical images in the wireless media. Intelligent exchange of bio-signals amongst hospitals needs efficient and reliable transmission. Watermarking adds ―ownership‖ information in multimedia contents to prove the authenticity, to verify signal integrity, or to achieve control over the copy process. This paper proposes a novel session based blind watermarking method with secret key by embedding binary watermark image into (Electrocardiogram) ECG signal. The ECG signal is a sensitive diagnostic tool that is used to detect various cardio-vascular diseases by measuring and recording the electrical activity of the heart in exquisite detail. The first part of this paper proposes a multi-resolution wavelet transform based system for detection ‗P',‗Q',‗R',‗S',‗T' peaks complex from original ECG signal of human being. ‗R-R' time lapse is an important component of the ECG signal that corresponds to the heartbeat of the concerned person. Abrupt increase in height of the ‗R' wave or changes in the measurement of the ‗R-R' interval denote various disorders of human heart. Similarly ‗P-P', ‗Q-Q', ‗S-S', ‗T-T' intervals also correspond to different disorders of heart and their peak amplitude envisages other cardiac diseases. In this proposed method the ‗P Q R S T'-peaks are marked and stored over the entire signal and the time interval between two consecutive ‗R'-peaks and other peaks interval are measured to detect anomalies in behavior of heart, if any. The peaks are achieved by the composition of Daubechies sub-bands wavelet of original ECG signal. The accuracy of the P, QRS and T components detection and interval measurement is achieved with high accuracy by processing and thresholding the original ECG signal. The second part of the paper proposes a Discrete Wavelet Transformation (DWT) and Spread Spectrum based watermarking technique. In this approach, the generated watermarked signal having an acceptable level of imperceptibility and distortion is compared to the Original ECG signal. Finally, a comparative study is done for the intervals of two consecutive ‗R-R' peaks, ‗P-R', ‗Q-T', ‗QTc', QRS duration, cardiac output between original P, QRS and T components detected ECG signal and the watermarked P,QRS and T components detected ECG signal.

A Robust Steganography Model Using Wavelet-Based Block-Partition Modification

An efficient steganographic method is proposed for embedding secret messages into gray scale and RGB colored images. In this paper, a wavelet domain steganography is adopted for hiding a large amount of data with high security, good invisibility and no loss of secret message. The information is embedded in those areas of the host image that contains high texture to reduce visibility of the embedded information in the host image. The qualified significant wavelet coefficients and their texture and sensitivity to gray value variations across different coarse scales (level 1, level 2 and level 3 wavelet decompositions) are utilized to determine the positions and the magnitudes to adaptively embed the secrete message. We consider the highly textured areas near the edges in high frequency subbands in the wavelet domain. The transformed cover image is divided into number of joint non-overlapping 4 × 4 blocks in each layer (R, G, and B layers). A difference value is calculated from the values of the adjacent pixels in each block, producing the partitioned difference image (PDI). The wavelet subbands are selected to calculate the changes. The selection of the range intervals is based on the characteristics of human vision's sensitivity to gray value variations from smoothness to contrast. The number of bits which can be embedded in each block varies and is decided by the width of the range to which the difference value of the two pixels and block histogram peak (Pk) belongs to. The embedded secret message can be extracted from the resulting stego-image and the original cover image is reversed. The proposed model will produce a high-capacity image steganography technique with acceptable level of imperceptibility and distortion in the cover image and high level of overall security. This solution is independent of the nature of the data to be hidden and produces a stego image with minimum degradation. Experimental results show the feasibility of the proposed methods. Various statistics attacks were also conducted to collect related data to show the security of the method. The experimental results show that the algorithm has a high embedding capacity and a good invisibility. Moreover PSNR of cover image with stego-image shows better results compared with other existing steganography approaches.

Data Hiding in Images in Discrete Wavelet Domain Using PMM

Over last two decades, due to hostilities of environment over the internet the concerns about confidentiality of information have increased at phenomenal rate. Therefore to safeguard the information from attacks, number of data/information hiding methods have evolved mostly in spatial and transformation domain.In spatial domain data hiding techniques,the information is embedded directly on the image plane itself. In transform domain data hiding techniques the image is first changed from spatial domain to some other domain and then the secret information is embedded so that the secret information remains more secure from any attack. Information hiding algorithms in time domain or spatial domain have high capacity and relatively lower robustness. In contrast, the algorithms in transform domain, such as DCT, DWT have certain robustness against some multimedia processing.In this work the authors propose a novel steganographic method for hiding information in the transform domain of the gray scale image.The proposed approach works by converting the gray level image in transform domain using discrete integer wavelet technique through lifting scheme.This approach performs a 2-D lifting wavelet decomposition through Haar lifted wavelet of the cover image and computes the approximation coefficients matrix CA and detail coefficients matrices CH, CV, and CD.Next step is to apply the PMM technique in those coefficients to form the stego image. The aim of this paper is to propose a high-capacity image steganography technique that uses pixel mapping method in integer wavelet domain with acceptable levels of imperceptibility and distortion in the cover image and high level of overall security. This solution is independent of the nature of the data to be hidden and produces a stego image with minimum degradation. Keywords—Cover Image, Pixel Mapping Method (PMM), Stego Image,Integer Wavelet Tranform.