Ahmed Al-Gindy

Abstract: This paper presents a new algorithm for colour digital image watermarking. The 24 bits/pixel RGB images are used and the watermark is placed on the green channel of the RGB image. The green channel is chosen after an analytical investigation process was carried out using some popular measurement metrics. The analysis and embedding processes have been carried out using the discrete cosine transform DCT. The new watermarking method has shown to be resistant to JPEG compression, cropping, scaling, low-pass, median and removal attack. This algorithm produces more than 65 dB of average PSNR.

Abstract: In this paper an image authentication technique that embeds a binary watermark into a host color image is proposed. In this scheme the colour image is first transformed from the RGB to the YCbCr color space. The watermark is embedded into the Y channel of the host image by selectively modifying the very low frequency parts of the DCT transformation. It is shown that the proposed technique can resist classical attacks such as JPEG Compression, low pass filtering, median filtering, cropping, and geometrical scaling attack. Moreover, the recovery method is blind and doesn't need the original host image for extraction.

Abstract: Summary A new frequency domain based watermarking scheme for colour images captured by mobile phone cameras is proposed. The proposed technique embeds personal mobile phone numbers inside the image. The aim of the scheme is to protect the copy right ownership of the image. Each bit of the decimal digits is inserted onto one low frequency coefficient of one of the DCT blocks of the host image. A DCT coefficient selection (DCS) process has been applied to increase the invisibility qualities, this process managed to find the coefficient with the maximum magnitude. Different embedding location depending on the spatial frequencies of the host image will be selected. The proposed algorithm achieves a high PSNR values and is found to be robust against JPEG compression and different image manipulation algorithms.

Abstract: This paper deals with a new blind robust watermarking technique for embedding two watermarks into a host image. The technique is based on embedding watermark information in sixteen low-frequency band coefficients of the DCT sub-blocks. The embedding process is based on changing the selected DCT-coefficients of the host image to odd or even values depending on the binary watermark's bit value. The proposed blind watermarking embedding has shown to be strongly robust against several attacks.

Abstract: This paper deals with a new blind technique for robust image watermarking in the DCT domain. The technique is based on embedding watermark information in eight low-frequency band coefficients of the DCT sub-blocks. Single watermark has been embedded multi-times in the host image. The embedding process is based on changing the selected DCT-coefficients of the host image to odd or even values depending on the binary watermark's bit value. The proposed blind watermarking embedding has shown to be strongly robust against several attacks.

Abstract: The increasing popularity of the internet means that digital multimedia are transmitted more rapidly and easily. And people are very aware for media ownership. However, digital watermarking is an efficient and promising means to protect intellectual properties. Based on the intellectual property attention in the information era, how to protect the personal ownership is extremely important and a necessary scheme. In this paper, we propose an effective video watermarking method based on a pseudo-3-D discrete cosine transform (DCT) and quantization index modulation (QIM) against several attacks. The watermark is mainly inserted into the uncompressed domain by adjusting the correlation between DCT coefficients of the selected blocks, and the watermark extraction is blind. This approach consists of a pseudo-3-D DCT, watermark embedding, and extraction. A pseudo-3-D DCT, which is taken DCT transformation twice, will be first utilized to calculate the embedding factor and to obtain the useful messages. Using the QIM, we embed the watermark into the quantization regions from the successive raw frames in the uncompressed domain and record the relative information to create a secret embedding key. This secret embedding key will further apply to extraction. Experimental results demonstrate that the proposed method can survive filtering, compressions, luminance change, and noise attacks with a good invisibility and robustness.

Abstract: Since the color image watermark has more bit information, it is a challenging problem to design a robust and blind color watermarking scheme for copyright protection. In this paper, a blind watermarking scheme based on singular value decomposition (SVD) is proposed. By analyzing the orthogonal matrix U via SVD, it is found that there exists a strong similarity correlation between the second row first column element and the third row first column element. Hence, this paper utilizes this property for image watermarking. Firstly, the 4 × 4 non-overlapping pixels block of each component in color host image is processed by SVD. And then, the color watermark is embedded by slightly modifying the value of the second row first column element and the third row first column one of U matrix, and the modified relation can be utilized to extract watermark. Experimental results, compared with the related existing methods, show that the proposed color image scheme has stronger robustness against most common attacks such as image compression, filtering, cropping, noise adding, blurring, scaling and sharpening et al.

Abstract: In this paper, a blind watermarking scheme based on Singular Value Decomposition (SVD) is proposed. By analyzing the orthogonal matrix U via SVD, it is found that there exists a strong similarity correlation between the second row first column element and the third row first column element. Hence, this work will utilize this property for image watermarking. Firstly, the 4x4 non-overlapping pixels block of each component in color host image is processed by SVD. And then, the color watermark is embedded by slightly modifying the value of the second row first column element and the third row first column one of U matrix, and the modified relation can be utilized to extract watermark. Hence, without resorting to the original watermark image and original host image, the embedded watermark can be easily extracted. The experiment results show that the proposed watermarking algorithm can ensure the invisibility and stronger robustness for the common image processing operations and geometric attacks, and the performance of this proposed method outperforms that of other proposed methods considered in this work.

Abstract: Digital images are often used in several domains. Large amount of data is necessary to represent the digital images so the transmission and storage of such images are time-consuming and infeasible. Hence the information in the images is compressed by extracting only the visible elements. Normally the image compression technique can reduce the storage and transmission costs. During image compression, the size of a graphics file is reduced in bytes without disturbing the quality of the image beyond an acceptable level. Several methods such as Discrete Cosine Transform (DCT), DWT, etc. are used for compressing the images. But, these methods contain some blocking artifacts. In order to overcome this difficulty and to compress the image efficiently, a combination of DCT and fractal image compression techniques is proposed. DCT is employed to compress the color image while the fractal image compression is employed to evade the repetitive compressions of analogous blocks. Analogous blocks are found by using the Euclidean distance measure. Here, the given image is encoded by means of Huffman encoding technique. The implementation result shows the effectiveness of the proposed scheme in compressing the color image. Also a comparative analysis is performed to prove that our system is competent to compress the images in terms of Peak Signal to Noise Ratio (PSNR), Structural Similarity Index (SSIM) and Universal Image Quality Index (UIQI) measurements.

Abstract: Blind watermarking targets the challenging recovery of the watermark when the host is not available during the detection stage. This paper proposes Discrete Shearlet Transform (DST) as a new embedding domain for blind image watermarking. Our novel DST blind watermark detection system uses a nonadditive scheme based on the statistical decision theory. It first computes the Probability Density Function (PDF) of the DST coefficients modeled as a Laplacian distribution. The resulting likelihood ratio is compared with a decision threshold calculated using Neyman–Pearson criterion to minimize the missed detection subject to a fixed false alarm probability. Our method is evaluated in terms of imperceptibility, robustness, and payload against different attacks (Gaussian noise, blurring, cropping, compression, and rotation) using 30 standard grayscale images covering different characteristics (smooth, more complex with a lot of edges, and high detail textured regions). The proposed method shows greater windowing flexibility with more sensitive to directional and anisotropic features when compared against discrete wavelet and contourlets.