Intelligent reversible watermarking in integer wavelet domain for medical images

The prime requirement of reversible watermarking scheme is that the system should be able to restore the cover work to its original state after extracting the hidden information. Reversible watermarking approaches, therefore, have wide applications in medical and defense imagery. In this paper, an intelligent reversible watermarking approach GA-RevWM for medical images is proposed. GA-RevWM is based on the concept of block-based embedding using genetic algorithm (GA) and integer wavelet transform (IWT). GA based intelligent threshold selection scheme is applied to improve the imperceptibility for a fixed payload or vice versa. The experimental results show that GA-RevWM provides significant improvement in terms of imperceptibility for a desired level of payload against the existing approaches.     

Hybrid watermarking of medical images for ROI authentication and recovery

Medical image data require strict security, confidentiality and integrity. To achieve these stringent requirements, we propose a hybrid watermarking method which embeds a robust watermark in the region of non-interest (RONI) for achieving security and confidentiality, while integrity control is achieved by inserting a fragile watermark into the region of the interest (ROI). First the information to be modified in ROI is separated and is inserted into RONI, which later is used in recovery of the original ROI. Secondly, to avoid the underflow and overflow, a location map is generated for embedding the watermark block-wise by leaving the suspected blocks. This avoids the preprocessing step of histogram modification. The image visual quality, as well as tamper localization, is evaluated. We use weighted peak signal to noise ratio for measuring image quality of watermarked images. Experimental results show that the proposed method outperforms the existing hybrid watermarking techniques.     

Hybrid robust watermarking for color images

In this paper, we present a blind and highly robust watermarking scheme method for color images by combining the advantages of both spatial and frequency domain. Watermark is generated for each channel (RGB) of the color image by extracting spatial domain features using Gray Level Co-occurence Matrix as well as a unique identification number. The watermark is embedded in Principal Component Analysis (PCA)-based less correlated low and high frequency sub bands in such a way that the perceptual quality of the image is preserved. Imperceptibility is achieved by embedding the watermark in less correlated sub bands and robustness is achieved by spreading the watermark using Laplacian Pyramid in contourlet transform. Simulation results show that the proposed scheme can survive various image processing and signal processing attacks. The proposed method achieves high transparency, imperceptibility and robustness compared to some of the existing schemes.     

Geometrically invariant image watermarking using SVR correction in NSCT domain

Based on the support vector regression (SVR) geometric distortions correction, we propose a robust image watermarking algorithm in nonsubsampled contourlet transform (NSCT) domain with good visual quality and reasonable resistance toward geometric attacks in this paper. Firstly, the NSCT is performed on original host image, and corresponding low-pass subband is selected for embedding watermark. Then, the selected low-pass subband is divided into small blocks. Finally, the digital watermark is embedded into host image by modulating the NSCT coefficients in small blocks. In digital watermark detecting procedure, the SVR geometrical distortions correction is utilized. Experimental results show that the proposed image watermarking is invisible, and robust against common image processing and some geometrical attacks.     

An efficient watermarking algorithm for medical images

Multimedia Tools and Applications - Medical images exchanged over vulnerable networks are sensitive to modifications or tampering which could lead to misdiagnosis, risking the lives of the...     

Chaotic based secure watermarking approach for medical images

In this paper, a chaotic based secure medical image watermarking approach is proposed. The method is using non sub-sampled contourlet transform (NSCT), redundant discrete wavelet transform (RDWT) and singular value decomposition (SVD) to provide significant improvement in imperceptibility and robustness. Further, security of the approach is ensured by applying 2-D logistic map based chaotic encryption on watermarked medical image. In our approach, the cover image is initially divided into sub-images and NSCT is applied on the sub-image having maximum entropy. Subsequently, RDWT is applied to NSCT image and the singular vector of the RDWT coefficient is calculated. Similar procedure is followed for both watermark images. The singular value of both watermarks is embedded into the singular matrix of the cover. Experimental evaluation shows when the approach is subjected to attacks, using combination of NSCT, RDWT, SVD and chaotic encryption it makes the approach robust, imperceptible, secure and suitable for medical applications.

     

Slantlet based hybrid watermarking technique for medical images

Multimedia Tools and Applications - Watermarking techniques are widely used for copyright protection, confidentiality and integrity issues in medical field. Reversibility, robustness, embedding...     

Hybrid JND model-guided watermarking method for screen content images

Multimedia Tools and Applications - With the prevalence of digital products like cellphone, tablet and personal computer, the screen content images (SCIs) consisting of text, graphic, and natural...     

空域彩色图像鲁棒零水印算法

针对传统变换域水印算法往往通过修改变换域系数来嵌入水印信号,影响图像不可感知性的问题,利用载体图像整体均值与分块均值之间大小关系的稳定性,提出一种新的空域彩色图像鲁棒零水印算法。算法直接在空域通过整体图像均值与分块均值之间的关系构造特征矩阵,之后将此特征矩阵与预处理后的水印信息进行异或运算构造零水印信息,预处理之后再注册到知识产权数据库里。提取水印信息时,通过投票策略得到最终提取的水印信息。大量的仿真实验结果表明,该算法对常规的信号处理攻击、行列平移、尺寸缩放和旋转等几何攻击具有较强的鲁棒性。与相似的鲁棒水印算法相比,对于大多数的攻击,该算法具有更优越的性能。     

A lossless DWT-SVD domain watermarking for medical information security

Multimedia Tools and Applications - The goal of this work is to protect as much as possible the images exchanged in telemedicine, to avoid any confusion between the patient’s radiographs,...     

Hybrid semi-blind image watermarking in redundant wavelet domain

Multimedia Tools and Applications - Image watermarking in wavelet domain has been found useful for copyright protection and rightful ownership. Classical wavelet transforms, like discrete wavelet...     

复合NSCT分解DCT变换和SVD分解的多重变换水印

为了提高水印的抗旋转攻击鲁棒性,加大水印的嵌入量,提出了一种基于非采样Contourlet变换（NSCT）和离散余弦变换（DCT）结合的双重变换域水印算法。对图像进行NSCT变换,将低频系数进行DCT变换,对DCT域低频系数进行奇异值分解（SVD）。经仿真实验表明,该算法对常规滤波、旋转有很好的鲁棒性,特别面对旋转攻击时,算法仍能很好地提取出水印信息。     

Quantization based multiple medical information watermarking for secure e-health

Multimedia Tools and Applications - In this paper, an improved wavelet based medical image watermarking algorithm is proposed. Initially, the proposed technique decomposes the cover medical image...     

一种多重变换域大容量水印方案研究

提出了多重离散Chirp-Fourier变换（M-DCFT）域水印方案。把多个Chirp类水印信息分别嵌入在不同重数的DCFT域,利用DCFT域Chirp信号的聚集性进行盲检测。以PSNR作为水印容量衡量指标,推导了多重DCFT域的水印容量公式。仿真结果表明,在相同的PSNR限制下,变换域水印容量随变换重数的增大而增加,且远大于空域水印容量。提出的水印方案可以选择把水印嵌入在不同重数的DCFT域,不仅嵌入方式灵活,而且具有更高的水印安全性。     

A robust semi-blind watermarking for color images based on multiple decompositions

In this paper, a robust semi-blind watermarking scheme for color images, based on multiple decompositions is proposed to preserve the copyrights of the owner. Using multiple decompositions, the gray watermark is embedded into a host color image. Prior to that, to enhance security the gray watermark is encrypted with Arnold transform and SVD by generating secret keys. The luminance component of the given host image is subjected to discrete wavelet transform(DWT), contourlet transform(CT), Schur decomposition and singular value decomposition(SVD) in sequence and finally the watermark is embedded. In the semi-blind extraction process, the watermark is extracted without the help of the original host image. Experimental results show that the proposed watermarking scheme has better visual imperceptibility and high robustness against image & signal processing attacks compared to other methods.     

Robust watermarking and compression for medical images based on genetic algorithms

A ROI (region of interest) of a medical image is an area including important information and must be stored without any distortion. In order to achieve optimal compression as well as satisfactory visualization of medical images, we compress the ROI by lossless compression, and the rest by lossy compression. Furthermore, security is an important issue in web-based medical information system. Watermarking skill is often used for protecting medical images. In this paper, we present a robust technique embedding the watermark of signature information or textual data around the ROI of a medical image based on genetic algorithms. A fragile watermark is adopted to detect any unauthorized modification. The embedding of watermark in the frequency domain is more difficult to be pirated than in spatial domain.     

Information hiding in medical images: a robust medical image watermarking system for E-healthcare

Electronic transmission of the medical images is one of the primary requirements in a typical Electronic-Healthcare (E-Healthcare) system. However this transmission could be liable to hackers who may modify the whole medical image or only a part of it during transit. To guarantee the integrity of a medical image, digital watermarking is being used. This paper presents two different watermarking algorithms for medical images in transform domain. In first technique, a digital watermark and Electronic Patients Record (EPR) have been embedded in both regions; Region of Interest (ROI) and Region of Non-Interest (RONI). In second technique, Region of Interest (ROI) is kept untouched for tele-diagnosis purpose and Region of Non-Interest (RONI) is used to hide the digital watermark and EPR. In either algorithm 8?×?8 block based Discrete Cosine Transform (DCT) has been used. In each 8?×?8 block two DCT coefficients are selected and their magnitudes are compared for embedding the watermark/EPR. The selected coefficients are modified by using a threshold for embedding bit a ‘0’ or bit ‘1’ of the watermark/EPR. The proposed techniques have been found robust not only to singular attacks but also to hybrid attacks. Comparison results viz-a - viz payload and robustness show that the proposed techniques perform better than some existing state of art techniques. As such the proposed algorithms could be useful for e-healthcare systems.     

区域能量和图像自相似的NSCT域图像融合

非降采样轮廓波变换(NSCT)不仅具有平移不变性,还拥有足够的冗余信息,可以更有效地提取源图像中的方向信息,使得融合后的图像更符合人眼的视觉特性.利用NSCT在图像处理中的优势,针对红外光与可见光图像的融合,提出了一种新的基于改进的区域能量和图像自相似的NSCT域图像融合算法.首先,利用NSCT将图像分解为一个低频子带和多个不同方向的带通子带;然后,对低频子带采用区域能量自适应加权融合规则,带通方向子带则利用图像自相似进行系数的融合;最后,对融合系数进行NSCT逆变换,以重构生成融合图像.实验结果表明:与一些现有算法相比,该算法的图像融合结果在人眼主观视觉标准和客观评价标准上均具有明显优势.