Image steganography based on sparse decomposition in wavelet space

, Article Proceedings 2010 IEEE International Conference on Information Theory and Information Security, ICITIS 2010, 17 December 2010 through 19 December 2010, Beijing ; 2010 , Pages 632-637 ; 9781424469406 (ISBN) Ahani, S ; Ghaemmaghami, S ; Sharif University of Technology

2010

Abstract

Sparse decomposition of wavelet coefficients of cover image blocks for data hiding is addressed in this paper. By using the proposed algorithm, the embedded secret message can be reliably extracted without resorting to the original image. We use all four sub-images (LL, LH, HL and HH) of the 2D wavelet transform for data embedding without losing the image imperceptibility. An over-complete dictionary matrix is estimated by using the KSVD dictionary learning algorithm, and then the secret message bits are inserted in the sparse representation of the wavelet coefficients over the estimated dictionary. This is believed to be one of the first approaches to the image data hiding that uses the...

Colour image steganography method based on sparse representation

, Article IET Image Processing ; Volume 9, Issue 6 , 2015 , Pages 496-505 ; 17519659 (ISSN) Ahani, S ; Ghaemmaghami, S ; Sharif University of Technology

Institution of Engineering and Technology 2015

Abstract

The authors address the use of sparse representation to securely hide a message within non-overlapping blocks of a given colour image in the wavelet domain. All four sub-images of the two-dimensional wavelet transform of two colour bands are used for data embedding without affecting the image perceptibility. Bit error rate of hidden data extraction is reduced to zero by introducing a novel refinement procedure in the proposed algorithm. The refinement procedure introduced solves the hidden bit extraction errors caused by the rounding process, the overflows and the nature of approximation in sparse decomposition. Capacity of the proposed method is calculated using necessary conditions for...

Steganography Based on Sparse Decomposition

, Ph.D. Dissertation Sharif University of Technology Ahani, Soodeh (Author) ; Ghaem Maghami, Shahrokh (Supervisor)

Abstract

The goal of this thesis is using sparse decomposition to design secure steganography algorithms to insert secret data into the different cover signals. We propose data embedding in higher semantic levels of the cover signal to reach this goal. Sparse decomposition represents a signal as a linear combination of its structural elements. Data insertion into the sparse coefficients slightly changes the effect of structural elements in the signal representation. So, quality of the stego signal is preserved and such a steganography method leads to higher imperceptibility. In addition, data insertion into the higher semantic levels leads to the higher undetectability. Steganalyzers use statistical...

A sparse representation-based wavelet domain speech steganography method

, Article IEEE/ACM Transactions on Speech and Language Processing ; Volume 23, Issue 1 , 2015 , Pages 80-91 ; 23299290 (ISSN) Ahani, S ; Ghaemmaghami, S ; Wang, Z. J ; Sharif University of Technology

2015

Abstract

In this paper, we present a novel speech steganography method using discrete wavelet transform and sparse decomposition to address the undetectability concern in speech steganography. The proposed speech steganography method exploits the sparse representation to embed secret messages into higher semantic levels of the cover signal, resulting in increased undetectability. The proposed method also yields improvements on both stego signal quality and embedding capacity, which are the two major requirements of a steganography algorithm. Our experimental results illustrate that the stego signals generated by the proposed method are perceptually indistinguishable from the original cover signals,...

Application of SMA Equipped Connection in Improving the Seismic Behaviour of Steel Structures Considering Soil-Structure Interaction

, M.Sc. Thesis Sharif University of Technology Ahani, Mona (Author) ; Rahimzadeh Rofouei, Fayyaz (Supervisor)

Abstract

Shape memory alloys (SMA) are materials with shape memory effect and high recentering capacity. Recently, application of SMAs in building structures and for the purpose of structure control during earthquake has been considered by many researchers. Researchers have tried to reduce the residual displacement of the structure after earthquake and also increase the dissipated energy by using this material in different forms such as wire, spring, bolt, etc.. In this research the seismic performance of steel structures equipped with SMA connection has been studied, considering the soil and structure interaction. The purpose of this research is to investigate the amount of required SMA bolts in...

Study of the Necessity and Feasibility of ASR Method of Artificial Recharge Projects in Hamoon-Jazmoorian Basin (in IRAN)

, M.Sc. Thesis Sharif University of Technology Ahani Amineh, Zainab Banoo (Author) ; Hashemian, Jamaloddin (Supervisor)

Abstract

Artificial recharge is an effective method of enhancing groundwater resources. Different methods are being used for aquifer recharge, including direct surface and subsurface method, Combined and indirect methods. Among these, direct surface methods such as flood spreading and ditch and furrow techniques are most commonly used methods. They are frequently used in Iran too, but what is disregarded herein, is the application of modern methods of artificial recharge such as ASR and ASTR. ASR and ASTR are methods of artificial recharge through injection wells/borings, in order to recharge deep-seated or those aquifers which are separated by impermeable stratum from the surface. These methods,...

Integrating spatial multi criteria decision making (smcdm) with geographic information systems (gis) for delineation of the most suitable areas for aquifer storage and recovery (asr)

, Article Journal of Hydrology ; Volume 551 , 2017 , Pages 577-595 ; 00221694 (ISSN) Ahani Amineh, Z. B ; Hashemian, S. J. A.D ; Magholi, A ; Sharif University of Technology

Elsevier B.V 2017

Abstract

Hamoon-Jazmoorian plain is located in southeast of Iran. Overexploitation of groundwater in this plain has led to water level decline and caused serious problems such as land subsidence, aquifer destruction and water quality degradation. The increasing population and agricultural development along with drought and climate change, have further increased the pressure on water resources in this region over the last years. In order to overcome such crisis, introduction of surface water into an aquifer at particular locations can be a suitable solution. A wide variety of methods have been developed to recharge groundwater, one of which is aquifer storage and recovery (ASR). One of the fundamental...