Watermarking Method For Color Images Research Articles

A robust and high-efficiency blind watermarking method for color images in the spatial domain

A robust and high-efficiency blind watermarking method for color images in the spatial domain

A Novel Color Image Watermarking Method with Adaptive Scaling Factor Using Similarity-Based Edge Region

This study aimed to deal with three challenges: robustness, imperceptibility, and capacity in the image watermarking field. To reach a high capacity, a novel similarity-based edge detection algorithm was developed that finds more edge points than traditional techniques. The colored watermark image was created by inserting a randomly generated message on the edge points detected by this algorithm. To ensure robustness and imperceptibility, watermark and cover images were combined in the high-frequency subbands using Discrete Wavelet Transform and Singular Value Decomposition. In the watermarking stage, the watermark image was weighted by the adaptive scaling factor calculated by the standard deviation of the similarity image. According to the results, the proposed edge-based color image watermarking technique has achieved high payload capacity, imperceptibility, and robustness to all attacks. In addition, the highest performance values were obtained against rotation attack, to which sufficient robustness has not been reached in the related studies.

A blind robust color image watermarking method based on discrete wavelet transform and discrete cosine transform using grayscale watermark image

AbstractWith the rapid development of internet technology, digital images are easily accessed and tampered by unauthorized users. Therefore, copyright of color images has become an important challenge in nowadays. Robust color image watermarking methods have emerged to provide copyright. However, robust watermarking methods must satisfy the requirements such as robustness, imperceptibility, capacity, and security. Therefore, researchers are focused on methods using grayscale watermark instead of the binary watermark to increase capacity. Grayscale watermark based robust color image watermarking methods are mostly semi‐blind and non‐blind. However, these methods have limited utilization areas since the original image, original watermark, or side information is required. To address these drawbacks, we propose a blind robust color image watermarking method using grayscale watermark. In the proposed watermark embedding procedure, one‐level discrete wavelet transform is performed on the Cb color component. Then, scrambled watermark pixels are hidden into coefficients of discrete cosine transform (DCT) matrices of LL subband by using dividing‐based new watermark embedding formula. In the watermark extracting procedure, watermark pixels are extracted from coefficients of DCT matrices by using dividing‐based extracting formula. The performance is demonstrated against various attacks and experimental results indicate that the presented method ensures robustness while preserving imperceptibility.

Artificial bee colony based perceptually tuned blind color image watermarking in hybrid LWT-DCT domain

A perceptually tuned blind digital watermarking method for color images in a hybrid lifting wavelet transform (LWT) and discrete cosine transform (DCT) domain is proposed in this work. The color watermark is scrambled by arnold transform before embedding to enhance the security level. The color host image is firstly transformed by lifting wavelet transform and the approximate sub-band is partitioned into different blocks each of size 8 x 8. The pixel values of each block are quantized using a quantization table. Each quantized-block is further decomposed by the DCT, to generate the AC coefficient matrix. Scrambled watermark is thereafter inserted into the AC coefficient matrix using the perceptually tuned dynamic embedding strength factor. The visual quality and robustness of the proposed watermarking are balanced by optimizing the value of perceptually tuned strength factor by the Artificial bee colony (ABC) optimization algorithm. Experimental results show that the color watermark is undetectable (with CPSNR > 40 dB) into the host image and robust enough (with NC > 0.9) to resist the image processing and manipulation attacks. Comparison analysis with other related watermarking methods highlights the efficacy of the proposed work.

A Novel Color Image Watermarking Method based on Digital Wavelet Transform and Hungarian Algorithms

A Novel Color Image Watermarking Method based on Digital Wavelet Transform and Hungarian Algorithms

A novel robust color image watermarking method using RGB correlations

In order to protect the copyright of the color image, a novel robust color image watermarking method using correlations of RGB channels is presented. RGB three channels of the color image have much strong correlations, which are stable under various image attacks, and thus these correlations can be mined to embed watermark for robustness. In order to keep RGB correlations and chrominance perception, the color image is considered as the third-order tensor, and tucker decomposition is employed to operate on the color image. At first, Tucker decomposition is used to generate the first feature image, which includes the most of image energies and correlations between three channels. Then, the first feature image is divided into non-overlap blocks, and the singular value decomposition (SVD) is used to decompose the block to compute the left-singular matrix. Finally, the stable coefficients relationship of the left-singular matrix is modified to embed watermark for obtaining the robustness. Experimental results show that the proposed method outperforms other existing color image watermarking methods, which can resist JPEG compression, salt & pepper noise, median filtering, scaling, blurring, low-pass filtering, and so on attacks.

A Color Image Watermarking Based on Tensor Analysis

Since most of the color image watermarking methods embed the watermark information in each channel or one channel of a color image, the redundant information of the color image cannot be sufficiently utilized, resulting in the poor ability to resist attacks. In this paper, a novel blind color image watermarking method based on the tensor domain is proposed, and it takes efficient account of the overall characteristics of color images and spreads the watermark information into three channels of color images based on tensor decomposition. Exploring the new tensor domain to embed and extract watermark information and the theoretical proof of the optimal embedding position of the core tensor are the major technical contributions of this paper. To be more specific, first, the RGB channels of the color image as a tensor are considered, and the tensor decomposition is used to obtain the core tensor. Then, based on the theoretical proof, the optimal embedding position of the core tensor is obtained, and the watermark information is embedded into the core tensor. Finally, the watermark information is spread to the three channels of the color image through the inverse tensor decomposition. The experimental results show that the proposed method has better invisibility and stronger robustness for the most common attacks.

A Robust Fractal Color Image Watermarking Algorithm

One of the main objectives of watermarking is to achieve a better tradeoff between robustness and high visual quality of a host image. In recent years, there has been a significant development in gray-level image watermarking using fractal-based method. This paper presents a human visual system (HVS) based fractal watermarking method for color images. In the proposed method, a color pixel is considered as a 3-D vector inRGBspace. And a general form of 3 × 3 matrix is utilized as the scaling operator. Meanwhile, the luminance offset vector is substituted by the range block mean vector. Then an orthogonalization fractal color coding method is achieved to obtain very high image quality. We also show that the orthogonalization fractal color decoding is a mean vector-invariant iteration. So, the range block mean vector is a good place for hiding watermark. Furthermore, for consistency with the characteristics of the HVS, we carry out the embedding process in theCIE La*b*space and incorporate a just noticeable difference (JND) profile to ensure the watermark invisibility. Experimental results show that the proposed method has good robustness against various typical attacks, at the same time, with an imperceptible change in image quality.

Performance Comparison of DCT and Walsh Transforms for Watermarking using DWT-SVD

This paper presents a DWT-DCT-SVD based hybrid watermarking method for color images. Robustness is achieved by applying DCT to specific wavelet sub-bands and then factorizing each quadrant of frequency sub-band using singular value decomposition. Watermark is embedded in host image by modifying singular values of host image. Performance of this technique is then compared by replacing DCT by Walsh in above combination. Walsh results in computationally faster method and acceptable performance. Imperceptibility of method is tested by embedding watermark in HL2, HH2 and HH1 frequency sub- bands. Embedding watermark in HH1 proves to be more robust and imperceptible than using HL2 and HH2 sub-bands.

Geometrically invariant color image watermarking scheme using feature points

Geometric distortion is known as one of the most difficult attacks to resist. Geometric distortion desynchronizes the location of the watermark and hence causes incorrect watermark detection. In this paper, we propose a geometrically invariant digital watermarking method for color images. In order to synchronize the location for watermark insertion and detection, we use a multi-scale Harris-Laplace detector, by which feature points of a color image can be extracted that are invariant to geometric distortions. Then, the self-adaptive local image region (LIR) detection based on the feature scale theory was considered for watermarking. At each local image region, the watermark is embedded after image normalization. By binding digital watermark with invariant image regions, resilience against geometric distortion can be readily obtained. Our method belongs to the category of blind watermarking techniques, because we do not need the original image during detection. Experimental results show that the proposed color image watermarking is not only invisible and robust against common signal processing such as sharpening, noise adding, and JPEG compression, but also robust against the geometric distortions such as rotation, translation, scaling, row or column removal, shearing, and local random bend.