A spiral based image watermarking scheme using Karhunen–Loeve and discrete hartley transforms

For several signal processing applications, the usefulness of Fast Unitary Transforms (FUT) is now well recognized [1-7]. For signal representation, filtering and encoding, it is well known that the Karhunen-Loeve (KL) Transform, based on signal statistics, is optimum in various senses, but the KL Transform is slow. Suboptimum FUT's allow a trade-off between performance and speed. In this paper, we compare and rank the KL, Fourier, Walsh-Hadamard, Haar, Discrete Cosine, Slant Walsh Hadamard and Slant Haar Transforms by their performance in applications and by the number of elementary operations they require. In encoding and filtering, recursive techniques are widely used and are generally fast. By considering both performance and computations we are able to compare directly recursive and transform algorithms. The comparison brings to light a performance versus computation bound for the two classes of processing techniques.

Due to the rise in many industrial environment applications involving distributed networked collaborative intelligent measurement systems, intelligent monitoring and multi-sensor information exchange of private information, digital image information security and hidden image authentication, tampering detection, correction, and automatic intelligent self-recovery have become critical concerns. Towards that end, there is a need for more secure, efficient, and robust-to-unauthorized-tampering digital image watermarking, information hiding and authentication schemes. In our prior work, we introduced non-blind watermarking schemes where the carrier and watermark images are available at the receiver's end. We also proposed a double-blind scheme where both the carrier and the watermark images are not available at the receiver's end, but at the expense of possible lower pixel tampering, authentication and automatic intelligent self-correction ability. This paper proposes a blind wavelet-based, high capacity, secure digital watermarking and information hiding scheme with higher tampering localization and authentication that nullifies the need to have the carrier image available at the receiving end. The proposed scheme also increases robustness to image authentication and automatic self-recovery and correction compared to our prior double-blind scheme. The scheme is high capacity and sustains hiding secret hidden and watermarking images of the same full size as an arbitrary-sized carrier image. One of the benefits of the blind watermarking scheme is that it allows usage of varying and arbitrary carrier images that are unknown and unavailable anywhere, including the receiver's end. This is to prevent hackers' recognition of a familiar carrier image and their potential unauthorized tampering. Here, in this paper, two grayscale images are inserted in a colored carrier image. Here the watermark image is used for authentication and tamper localization. The second image is used as ownership or encoded secret hidden message image. The Arnolds Transform is used to introduce added security to a hidden image. The proposed scheme uses an embedded correction matrices mechanism for the extracted hidden information self-recovery from various tampering and digital attacks by unauthorized hackers.

In contrast to many image watermarking schemes, the suggested method is implemented in the JPEG compressed domain with no transcoding or decompression. Therefore, this scheme is highly efficient in real-time applications and suitable for multimedia information, which is rarely available in an uncompressed form. The proposed watermarking scheme is very flexible, and can be tailored to meet the requirements of different real applications. In order to attain a real-time watermarking capability, the proposed system avoids many of the computation steps associated with JPEG compression. Specifically, the forward and inverse DCT do not require to be calculated, nor do any of the computations associated with quantization. Robustness against JPEG compression and additive noise attacks is achieved with the proposed system. A further advantage of the suggested technique is that it allows a watermark to be detected in an image without referencing to the original image, or to any other information used in the watermark embedding process. At the decoder, only entropy decoding is enough to detect watermark and other steps of image decoding are not necessary for detection. The experimental results show how different capacity can be achieved in the range of 1 to 4096 bits for a grayscale 512×512×8 bit image. The watermarking algorithm reduces the quality about 0.65 dB, which is excellent for a watermarking system in compressed domain.

DWT-SVD digital watermarking scheme which is based on the combination of Discrete Wavelet Transform and Singular Value Decomposition is a recent digital watermarking technique and has become popular due to its robustness against various attacks. In this paper, we present an image watermarking scheme which combines previous DWT-SVD based methods which guarantees robustness without increasing algorithm complexity. In order to tackle the common drawback of existing DWT-SVD watermarking scheme, we also introduce a "reverse embedding' technique and use scaled singular values. Because our proposed method combines the strength of previous methods, it is able to provide a comprehensive and much improved robustness against various kinds of attack and this is shown in the simulations. The reverse embedding technique also avoids negative film effect which is common in existing DWT-SVD image watermarking scheme.

These days, researchers have used many techniques in e-multimedia data for intellectual property protection. One of these important techniques is watermarking which is superior to Digital Signature because it does not rise overhead and it can prevent unauthorized users from misusing digital information. However, the number of attacks with aim of distorting watermark signal or disturbing watermarks detecting are exploding. Consequently, the watermark techniques have became more complicated, but still they are not fully robust against some geometric distortions. To overcome this issue and to be enough robust against the malicious attacks, and provide a high level of imperceptibility,the watermark schemes have discovered and developed the advantages by means of Singular-value decomposition. Therefore, in recent decades there has been a significant increasing in using of SVD domain in many new image watermarking schemes, which show high robustness and imperceptibility. This discussion of SVD in image watermarking schemes included: a concise overview on watermarking systems, a brief review on SVD properties in image processing and its weaknesses, the concept of SVD components, the main classification of different SVD based image-watermarking schemes; a brief summary of various secure SVD-based watermarking techniques and all major SVD coefficients modifying strategies are presented. In addition, potential issues and some existing solutions and guidelines are provided. Furthermore, the performance comparisons of the discussed techniques are presented in tabular format. This article contribution provides essential and potential information for the researchers to design, develop and implement efficient robust and hybrid SVD-based image watermarking systems.

Geometrically resilient digital watermarking scheme based on radial harmonic Fourier moments magnitude

A new structure-preserving quaternion QR decomposition method for color image blind watermarking

Quantization parameter based blind watermarking schemes are very popular. These schemes work in spatial domain as well as in various transform domains such as wavelet, discrete cosine, and real oriented wavelet. These schemes utilize one bit (binary) image as a watermark. However, in general, watermarks are any n bit image, where n ≥ 1. Therefore, these schemes are not suitable for the watermarks with n > 1. In this paper, we extend the existing work on blind watermarking schemes for n bits watermark images. The ‘division algorithm’ is used as a key component to develop the extended schemes. The proposed scheme is implemented in spatial domain. Experiments are done on one bit, two bits and eight bits watermark images. The results are investigated qualitatively by visualization, and measured quantitatively by peak-signal-to-noise-ratio (PSNR) and normalized correlation coefficient (NC). The results of the existing and proposed watermarking schemes are same for n = 1. The results of the proposed watermarking scheme are reliable for n > 1. A formula is proven for lower bound on PSNR, which is a key finding in the watermarking community. The formula is verified experimentally.

A novel gray-scale image watermarking using hybrid Fuzzy-BPN architecture

In this paper, an image watermarking scheme is presented, in which Least Significant Bit and discrete cosine transform are used. The discrete cosine transform is performed on the original host image, and the secret watermark image is embedded into the coefficient of discrete cosine transform, which will replace the least significant bit. The embedded secret watermark bit will cause minimal distortion of the original host image, but we cannot find the difference of the original host image and the watermarked image. The experiment based on this algorithm demonstrates that the watermarking is robust to the common signal processing techniques, including noise attack, JPEG Compression attack and so on.

We present a new scheme for digital watermarking and secure copyright protection of digital images using non-negative matrix factorization and singular value de-composition approaches. The proposed method improves the performance of the data embedding system effectively, and it is resistant to a variety of intentional attacks and normal visual processes. The experimental results clearly illustrate the much improved performance of the proposed watermarking methodology in comparison with existing techniques.

In this research, a novel approach for processing of single images and image sequences by using the Hierarchical Adaptive Karhunen-Loeve (KL)-based Transform (HA-KLT) is presented This approach is also suitable for block image coding, and for intra-frame processing of groups of correlated images. The main objective of the new transform is to achieve a high decorrelation of the image blocks (resp., images in the processed groups) as a result of the multi-level processing through adaptive KL transform of the sub-blocks (resp., sub-groups), on which the corresponding blocks (groups) are divided. After the execution of each hierarchical transform level, the sub-blocks (sub-groups) are rearranged in correspondence to their mutual correlation, starting from these, with maximum correlation. The kernel of the multi-level transform is the Adaptive KL Transform (AKLT), whose transform matrix could be a size 2 × 2 or 3 × 3. In the work, the algebraic method is presented, which calculates the elements of the AKLT matrix of size 2 × 2 and 3 × 3. Here the algorithms for 2D HA-KLT and 3D HA-KLT are also given in detail for the blocks of a single image and for the inter-frame processing of groups of images. The evaluations of the computational complexity of these algorithms are obtained, compared to that of the famous KLT. The basic advantages of the new approach for image processing through HA-KLT are a lower computational complexity and the parallel recursive calculations with small number of hierarchical levels, which opens the ability for real-time coding of video sequences. The HA-KLT algorithms are a basis for the creation of new efficient methods for compression of groups of correlated images and single images without visual loss, compression with motion compensation for TV and multi-view images, compression of medical and multispectral images, image fusion, face recognition in the reduced features’ space, object tracking in video sequences, among others.

Approximation of the Karhunen–Loève transformation and its application to colour images

In recent years, with the rapid development of internet, digital data has been widely used in various science and engineering applications. But, this development has also led to several threats and attacks from the intruders. Most of the organizations are very much concerned about the Illegal copyright activities which have become a series issue. A number of copyright protection schemes have been developed in the literature. Watermarking is one of the best known methods for copyright protection. Earlier Bit Error Rate (BER) is been observed to provide good results for choosing the optimal feature region from the watermarked image. However it fails to produce more accurate image quality measures. This research work mainly focuses on a novel technique implemented based on the simulated attacking approach and the GA-based Multi Dimensional Knapsack Problem (MDKP) solving technique to select the most sufficient feature regions for robust digital image watermarking without affecting the image quality. A major limitation in existing methods is the security problems which lead to decrease in the integrity of digital watermarking scheme. With that problem, the definite optimization problems (variant problems) cannot be resolved using genetic algorithms. To focus on the above mentioned problems, the proposed work uses two approaches. Chaotic Iterative Process encryption scheme is used to solve the security problems for watermarking image. Next, the optimal feature points can be chosen from the watermarked image by Modified version of Peak Signal Noise Ratio (MPSNR). MPSNR is based on the enhanced quality measurement of which point opposes the predefined and undefined attacks. With those two approaches the PSO algorithm is employed as a search strategy for identifying an optimal feature subset. The experimental results illustrates that comparing with various well-known feature-based techniques, the proposed method shows better performance in robust and more secure digital watermarking.

The main objectives of digital image watermarking schemes are to provide acceptable level of both imperceptibility and robustness for wide variety of host and watermark images. To support watermarking scheme in accomplishing these objectives, suitable watermark strength is identified in the form of scaling factor using Dynamic-PSO (DPSO) for colored images. A non-blind, DWT-SVD-based watermarking scheme is used to embed watermark in host image. Results achieved through DPSO are compared with PSO and other widely accepted variants of PSO. Experiment results demonstrate that performance of underline watermarking scheme when used with DPSO is better than other variants of PSO.