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The growing use of the internet results in significant difficulties for the copyright protection of images. To resolve the copyright problem, a scheme is proposed that utilizes the advantages of Zigzag scanning (ZS), Schur decomposition (SD), Discrete cosine transform (DCT) and Redundant discrete wavelet transform (RDWT). In the proposed scheme, Henon map is applied on the watermarked image for its secure transfer and further enhancement of the security. Medical image security assurance is the need of the hour. Therefore, ultrasound images of the liver of six different patients are taken for experimental result analysis. The use of Singular value decomposition (SVD) is avoided here due to its false positive problem. RDWT is used to split the input ultrasound liver image into different sub-bands. Then DCT is applied on the suitable sub-band to improve the robustness of the presented work. The ZS is used to avoid artifacts which may occur at higher value of the gain factor. SD and RDWT are applied to the watermark logo (MNNIT logo) and selective pixel adding is used to embed the watermark logo into the host image. The authentication process is done by using binary robust invariant scalable keypoints (BRISK) features. The presented scheme perform satisfactorily against various attacks such as Histogram equalization, Region of interest (ROI) filtering, Cropping, Scaling, Rotation, Average and Median filtering attacks, Salt and Pepper, Gaussian noise attack, Flipping, etc. The proposed scheme shows better performance as compared to existing schemes in terms of various performance parameters such as Peak signal-to-noise ratio (PSNR), Structural similarity index measurement (SSIM) and Normalized correlation coefficient (NCC). [ABSTRACT FROM AUTHOR]

Digital image watermarking provides security, copyright protection, and authenticity to multimedia content by embedding digital content like text, image, and video. In the modern digital age, watermarking of digital images is an essential aspect of providing authenticity to digital content. Digital image watermarking is also used for the authenticity of the medical image in telemedicine applications. In these applications, digital image watermarking provides security to various medical images like Computerized tomography (CT) scans, Magnetic resonance imaging (MRI) images, and X-radiation (X-ray) images. In the past decades, many intellectuals have been working in the field of image watermarking to provide various characteristics features to watermarking like sufficient embedding capacity, strong robustness, and better imperceptibility. This paper covers watermarking techniques based on Schur decomposition and various types of moments like Zernike moment, Fourier harmonic moments, polar harmonic moments, etc. A survey on watermarking techniques suitable for telemedicine applications which include various medical images like CT-scan, MRI image, and X-ray images, is also presented. Various performance measures proposed by different researchers are also discussed, and the suitability of these measures for watermarking schemes is analysed under various attacks. In this paper, novel classification of watermarking schemes, recent essential requirements for different categories of image watermarking applications are covered. A tabular comparison of various watermarking schemes based on different families of moments are presented and also a comparative analysis of outcomes of different categories of moment based watermarking schemes is included. Various challenges and opportunities are also included to make this review more comprehensive. [ABSTRACT FROM AUTHOR]

One method for securing multimedia data, and images in particular, from malicious attacks is watermarking, which involves adding a signature to the images. Traditional watermarking techniques, however, have drawbacks when used on sensitive images like those used in medicine. A reliable and blind watermarking method is suggested in this work to secure medical image exchanged in telemedicine. Medical image watermarking enables accurate patient identification, prevents scan confusion, and minimizes the risk of diagnostic mistakes that might have detrimental effects. In this method, three distinct transformations are used to get the frequency content of the picture. The low frequency subbands are subsequently subjected to Schur decomposition. In order to incorporate the watermark bits, the resultant upper triangular matrix values are modified. The suggested approaches effectively retain a considerable quality of watermarked images, according to experimental results on imperceptibility and robustness, and are resistant against various common attacks. [ABSTRACT FROM AUTHOR]

In this proposed work, a dual image watermarking algorithm is used to protect the data against copyright violations. In this work, the DICOM image is used as a host image. Two watermark images used are the MNNIT logo and the personal data of the patient. This method utilizes the advantages of Schur decomposition, lifting wavelet transform (LWT), discrete cosine transform (DCT) and singular value decomposition (SVD). The scaling factor is a vital parameter of watermarking technique. The firefly optimization technique is used to get the optimized scaling factor. The Speeded-up robust features (SURF) are used for watermarking authentication. To evaluate the performance of the proposed algorithm, peak signal-to-noise ratio (PSNR), normalized correlation coefficient (NCC), and structural similarity index measurement (SSIM) are used. The proposed method is tested against various attacks such as Salt and Pepper noise, Gaussian noise, Gaussian low pass filter, Average filter, Median filter, Histogram equalization, Sharpening, Rotation and Region of interest filtering. The proposed algorithm shows a high level of robustness and imperceptibility. It is found that the features of the input host image and the watermarked image are matching correctly on applying the SURF technique. [ABSTRACT FROM AUTHOR]

Medical images became a very important information tool for health professionals. Currently, the medical image acquired in a hospital or an imaging center can be shared among several health professionals to facilitate patient management and improve medical information management. In this work, we proposed a robust and blind watermarking approach to adequately secure medical images exchanged in telemedicine. This approach ensures the traceability and integrity of the medical and essential image for data security in the field of telemedicine. In this approach, the watermark consists of the patient's photography as well as the patient's data and the data related to the medical image acquisition. These combined data will thus guarantee the successful authentication of the image as well as the patient. A hash of this necessary information will be appropriately included in the watermark to ensure the integrity of the hidden data. The proposed watermarking in this approach remains a substitutive process. The frequency content of the image is acquired using transforms. Schur decomposition is then applied to the obtained mid-frequency subbands. Finally, the watermark bits will be substituted to the upper triangular matrix values obtained. Imperceptibility and robustness experimental results show that the proposed methods adequately maintain a significant quality of watermarked images and are remarkably robust against several conventional attacks. Since those schemes offer a reasonable imperceptibility and robustness, they could be useful for copyrights protection of medical images. [ABSTRACT FROM AUTHOR]

A novel robust tamper detection medical watermarking scheme is proposed in the transform domain for authentication and detecting tamper pixels of medical images. In this scheme, 2-level Discrete Wavelet Transform is applied to a significant image to produce four sub-bands (SB) (CLL,CLH,CHL,CHH). Coefficients of LL sub-bands are considered in embedding the watermark. The SB is partitioned into blocks to overcome image processing attacks. LSB is set to zero for each block and then Schur decomposition is applied in generating Authenticated Block Bits (ABB). In developing confusion to the intruders, the watermark is scrambled using Quantum Hilbert Image Scrambling. Watermarking helps in authentication and tamper detection of the significant image after tampering. The scheme is tested with image processing attacks for robustness. Peak signal to noise ratio (PSNR) and Normalized Cross-Correlation (NCC) metrics are utilized as metrics in evaluating the proposed scheme with PSNR greater than 30dB and NCC values nearer to 1 without attacks and even with attacks, NCC values are greater than 0.95, which shows the robustness of the proposed scheme. [ABSTRACT FROM AUTHOR]

To improve the robustness of image watermarking algorithms against geometric attacks such as cropping, rotation, scaling, shearing, projective mapping, a robust image watermarking algorithm based on DT CWT and Schur decomposition is proposed. Firstly, we use Dual Tree Complex Wavelet Transform (DT CWT) to decompose the U component of the original image (cover image), the decomposed low frequency component is divided into non-overlapping N × N blocks, and Schur decomposition is applied in each block. Secondly, we modify maximum primary diagonal value of the upper triangular matrix of each block to embed the watermark. Finally, the Scale Invariant Feature Transform (SIFT) features of the watermarked image (stego-image) is saved as the SIFT key for watermark extraction. When extracting the watermark, we first use the SIFT features of stego-image and changed stego-image to obtain the geometric torsion, thereby a spatial synchronization can be guaranteed. And we then use the maximum election statistics to improve the quality of the extracted watermark. Experiment results show that the proposed algorithm can resist geometric attacks, and is more robust than the existing watermarking methods. [ABSTRACT FROM AUTHOR]

An invisibility and blind watermarking algorithm based on Schur decomposition and non-subsampled contourlet transform is designed to protect copyright. The cover image is decomposed by the non-subsampled contourlet transform. And the low pass sub-band of the non-subsampled contourlet transform is divided into 8 × 8 non-overlapping blocks. Then each block is performed by the Schur decomposition and the watermark information is embedded by modifying the largest energy element in the Schur domain. Before embedding into the cover image, the original watermark is scrambled with logistic map and Arnold transform to ensure the security. Besides, a synchronization mechanism based on scale invariant feature transform is designed for resisting geometrical attacks. The proposed watermarking algorithm is evaluated with structural similarity index, peak signal to noise ratio and bit error rate. Experimental results demonstrate that the proposed watermarking scheme performs better in terms of invisibility, robustness and payload than other similar schemes. [ABSTRACT FROM AUTHOR]

The widespread application of the Internet makes the protection of image copyright face serious challenges. For resolving this problem, this paper designs a blind color digital image watermarking algorithm which meets the requirements of invisibility, security and robustness. The advantages of the proposed method include the following two points: 1) the proposed method uses Affine transformation with large key space to encrypt the watermark information; 2) Schur decomposition with low complexity is selected and performed on the matrix blocks in different color channels of the host image. In this proposed method, the watermark embedding and blind extraction are completed by quantizing the eigenvalues on the diagonal of the decomposed matrix with different quantization steps. Experimental results show that the proposed method not only has good invisibility, but also has high security and strong robustness. [ABSTRACT FROM AUTHOR]

The vulnerability of digital audio signals for different types of risks requires an imperceptible and robust digital audio watermarking scheme. In this research, we propose creating one such imperceptible and robust hybrid watermarking scheme based on a discrete wavelet transform (DWT) and Schur decomposition hybrid method. The proposed scheme embeds the foreground bits of the watermarking image into the least significant bit of the diagonal coefficients of the triangular matrix S generated from Schur decomposition. Schur decomposition is applied on the second sub-band HL2 generated from applying a second-level 2D-Haar DWT on the first channel of the original audio signal. We analyze the proposed digital audio watermarking scheme's performance in terms of signal to noise ratio (SNR), objective difference grades (ODG), and subjective difference grades (SDG) that resulting 81.43, 4.78 and 0.184, respectively. The resulting of payload capacity, NC, and BER are as high as 319.29 bps, 0.9911, and 0.0135, respectively. Experimental results confirm that the proposed scheme is inaudible and robust against common types of attacks such as Gaussian noise, re-quantization, re-sampling, low-pass filter, high-pass filter, echo, MP3 compression, and cropping. In comparison with state-of-the-art audio watermarking schemes, the proposed scheme's performance is superior in term of imperceptibility, robustness, and data payload size. [ABSTRACT FROM AUTHOR]

Based on quaternion Hadamard transform (QHT) and Schur decomposition, a novel color image watermarking scheme is presented. To consider the correlation between different color channels and the significant color information, a new color image processing tool termed as the quaternion Hadamard transform is proposed. Then an efficient method is designed to calculate the QHT of a color image which is represented by quaternion algebra, and the QHT is analyzed for color image watermarking subsequently. With QHT, the host color image is processed in a holistic manner. By use of Schur decomposition, the watermark is embedded into the host color image by modifying the Q matrix. To make the watermarking scheme resistant to geometric attacks, a geometric distortion detection method based upon quaternion Zernike moment is introduced. Thus, all the watermark embedding, the watermark extraction and the geometric distortion parameter estimation employ the color image holistically in the proposed watermarking scheme. By using the detection method, the watermark can be extracted from the geometric distorted color images. Experimental results show that the proposed color image watermarking is not only invisible but also robust against a wide variety of attacks, especially for color attacks and geometric distortions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

With the rapid development of computer technology, the copyright protection of color image is becoming a more and more urgent problem. In this paper, an improved color image blind watermarking scheme based on Schur decomposition is proposed, which is different from using the binary or gray-level image as watermark. By analyzing the 4 × 4 unitary matrix U and the upper triangular matrix D of Schur decomposition, it is found that not only the embedding column c of matrix U is decided by the column of the maximum eigenvalue of the matrix D, but also the entries between the second row the c-th column and the third row the c-th column in the matrix U have strong similarity. These properties will be used for embedding watermark and extracting watermark in the blind manner. The novelty of this paper includes: 1) Using the results features obtained by Schur decomposition to embed or extract watermark with blind manner; 2) The embedded watermark is color image which has more watermark information than random sequence, binary image or gray-level image. Experimental results show that the proposed watermarking algorithm has better performance, such as in the aspects of the invisibility, robustness, computational complexity, security, capacity etc., compared with other proposed methods considered in this work. [ABSTRACT FROM AUTHOR]

In this paper, we present a new digital watermarking scheme for ownership protection. The algorithm embeds the watermark in the Schur decomposition components of the cover image. We also show that this algorithm is noninvertible. Comparisons with other algorithms indicate that the proposed algorithm is robust against most common attacks including geometrical distortions and jpeg compression attacks. Simulations show that the performance of this algorithm outperforms the closely related singular value decomposition based algorithms. More specifically, the proposed algorithm is more robust and requires less number of computations. In addition, our algorithm does not suffer the false positive detection problem inherent in SVD based algorithms. [ABSTRACT FROM AUTHOR]