Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> An application of the fractional Fourier transform for the multimedia copyright protection is proposed in the paper. The watermark robustness as well as statistical performance are considered. <s> BIB001 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> A two-dimensional (2-D) signal with a variable spatial frequency is proposed as a watermark in the spatial domain. This watermark is characterized by a linear frequency change. It can be efficiently detected by using 2-D space/spatial-frequency distributions. The projections of the 2-D Wigner distribution-the 2-D Radon-Wigner distribution, are used in order to emphasize the watermark detection process. The watermark robustness with respect to some very important image processing attacks, such as for example, the translation, rotation, cropping, JPEG compression, and filtering, is demonstrated and tested by using Stirmark 3.1. <s> BIB002 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> The paper presents a novel watermarking scheme able to resist geometric attacks. The proposed method performs imperceptible watermarking of images in the spatial domain. To generate resistance to scaling and rotation attacks, two generalized Radon transformations of the image are introduced, while resistance to translation is accomplished through a localization of the watermarking method based on feature points of the image. The original image is not required for the detection process. Experimental evaluation demonstrates that the proposed scheme is able to withstand a variety of attacks including common geometric attacks. <s> BIB003 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> Three novel blind watermarking techniques are proposed to embed watermarks into digital images for different purposes. The watermarks are designed to be decoded or detected without the original images. The first one, called single watermark embedding (SWE), is used to embed a watermark bit sequence into digital images using two secret keys. The second technique, called multiple watermark embedding (MWE), extends SWE to embed multiple watermarks simultaneously in the same watermark space while minimizing the watermark (distortion) energy. The third technique, called iterative watermark embedding (IWE), embeds watermarks into JPEG-compressed images. The iterative approach of IWE can prevent the potential removal of a watermark in the JPEG recompression process. Experimental results show that embedded watermarks using the proposed techniques can give good image quality and are robust in varying degree to JPEG compression, low-pass filtering, noise contamination, and print-and-scan. <s> BIB004 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> Recently, watermarking synchronization and spread spectrum watermarking schemes have become two interesting, new focuses of study. In this paper, we propose a method based on the synchronization pre-estimation in order to resist geometric attacks. First, we utilize the global features by testing them against translation, rotation and scaling, and present a simple method to estimate the geometric transform kernel of the two-dimensional gray image. Maps, applying some correlative barycenters to the original are produced that can accurately reflect the affine transform feature of the image. Furthermore, unknown variables existing in the kernel of the transform are calculated. Secondly, the watermark is directly embedded in the spatial domain. Watermarking tracing is well performed on the watermarked image instead of performing an inverse geometrical transform on it. Experimental results show that the proposed scheme can work well under several kinds of geometrical attacks. <s> BIB005 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> A novel digital watermaking embedding and detecting algorithm for image is presented, which uses the chrip signal as a watermark and embeds in the fractional Fourier transform (FRFT) domain of the image, and the watermark position and the transform order are used as the encryption keys. With the help of the property of the impulse characteristic in the FRFT domain for chirp signal, the watermark can be detected conveniently. The experiments results have show that the proposed algorithm not only is of good imperceptibility and security and is very robust to JPEG compression and to noise attacks, but also can provide protection under the cropping and the filtering. <s> BIB006 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> In this paper, a new watermarking scheme in the joint time-frequency domain is introduced. Wigner distribution is used to transform an image into the spatial-spectral domain. The proposed method selects the time-frequency cells to be watermarked based on the particular image's energy distribution in the joint domain. This approach ensures the imperceptibility of the embedded watermark. It is shown that embedding in the time-frequency domain is equivalent to a nonlinear embedding function in the spatial domain. A corresponding watermark detection algorithm is also introduced. The performance of the proposed watermarking algorithm under possible attacks, such as noise, re-sampling, rotation, filtering, and JPEG compression is illustrated. <s> BIB007 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> In this paper, we propose an image authentication scheme in which image features are embedded for copyright protection and content-tampering detection. The features are based on the invariance of the relationship among SVD coefficients. The proposed method is sensitive to malicious manipulations and robust to lossy compressions or regular image operations, such as brightening, shifting, averaging, rotation, and so on. Several experiments demonstrated that the proposed scheme could efficiently detect locations which have been tampered with and effectively resist several types of attacks. Moreover, stego images based on our proposed method have high visual quality. <s> BIB008 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> The major disadvantage of existing watermarking methods is their limited resistance to extensive geometric attacks. In addition, we have found that the weakness of multiple watermark embedding methods that were initially designed to resist geometric attacks is their inability to withstand the watermark-estimation attacks (WEAs), leading to reduce resistance to geometric attacks. In view of these facts, this paper proposes a robust image watermarking scheme that can withstand geometric distortions and WEAs simultaneously. Our scheme is mainly composed of three components: 1) robust mesh generation and mesh-based watermarking to resist geometric distortions; 2) construction of media hash-based content-dependent watermark to resist WEAs; and 3) a mechanism of false positive-oriented watermark detection, which can be used to determine the existence of a watermark so as to achieve a tradeoff between correct detection and false detection. Furthermore, extensive experimental results obtained using the standard benchmark (i.e., Stirmark) and WEAs, and comparisons with relevant watermarking methods confirm the excellent performance of our method in improving robustness. To our knowledge, such a thorough evaluation has not been reported in the literature before <s> BIB009 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> This paper demonstrates the usefulness of spatial/spatial-frequency representations in image quality assessment by introducing a new image dissimilarity measure based on 2D Wigner-Ville distribution (WVD). The properties of 2D WVD are shortly reviewed, and the important issue of choosing the analytic image is emphasized. The WVD-based measure is shown to be correlated with subjective human evaluation, which is the premise towards an image quality assessor developed on this principle. <s> BIB010 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> We propose a novel watermarking algorithm based on discrete fractional random transform. Random block selection and high amplitude selection techniques have been employed to improve the robustness of the watermarking algorithm. The imperceptibility of the watermarking is improved by adjusting the intensity of phase shift keying. Simulations under several conditions are given to verify the effectiveness of the proposed scheme. The results have shown the proposed algorithm is robust against the attacks of cropping, noising and low-pass filtering. <s> BIB011 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> We describe the implementation of a watermark embedding technique for images using the discrete fractional Fourier transform. The idea is that a 2D discrete fractional Fourier transform of the image is computed. In this transform domain, a normal distributed random sequence with certain characteristics is used to modify the transform coefficients in the middle range of magnitude. Then the inverse transform is applied to give the watermarked image. The detection is based on performing the same transform operation. The watermark is recognized if there is a strong correlation with the embedded watermark. That is when the correlation is above some threshold. <s> BIB012 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> In this paper, a dual digital watermarking embedding and detecting algorithm for image is presented, which uses the robust watermark and fragile watermark embed in the fractional Fourier transform (FRFT) domain of the image, and the watermark position and the transform order are used as the encryption keys. The experiment results show that the embedded watermark is perceptually invisible and robust to various image processing operations. Most importantly, the tampered place can be identified accurately. <s> BIB013 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> This paper presents a novel noise-robust scheme for watermark embedding and extraction, applicable on the broad scientific field of information security, including digital encryption for secure transmission. The proposed scheme employs Fourier coefficients for moment-based image analysis and the fractional Fourier transformation for watermark embedding. This approach maintains the advantages of spatial and frequency domain representations, offers two additional degrees of freedom associated with the fractional Fourier transformation angles, whereas it provides increased detectability of the embedded watermarks at the received end. The experimental evaluation of the proposed scheme leads to the conclusion that it is more robust in the presence of noise than previous schemes for watermark embedding and extraction. <s> BIB014 </s> Fractional Fourier transform as a signal processing tool: An overview of recent developments <s> Watermarking <s> Thank you for reading handbook of image and video processing. As you may know, people have look numerous times for their favorite novels like this handbook of image and video processing, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they juggled with some harmful virus inside their computer. handbook of image and video processing is available in our book collection an online access to it is set as public so you can get it instantly. Our books collection hosts in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the handbook of image and video processing is universally compatible with any devices to read. <s> BIB015
The FRFT and its counterparts have not be fully exploited in the field of the multimedia due to several plausible reasons. Firstly, several well-established transforms are already used in the multimedia applications (e.g., DCT, DST, Walsh, DWT, DFT). Secondly, multimedia applications are commonly subject to some sort of standardization. Also, a relatively short history of the fast algorithms for the FRFT realization and a short period for the detailed study of the FRFT properties limit its wider usage in this area. The third reason is that this transform with a relatively long history in the other signal processing related disciplines, is still relatively unknown in the multimedia systems. However, this situation is gradually changing with more papers focusing on this transform. Here, it is worthwhile mentioning the application in the digital watermarking (e.g., BIB001 BIB006 BIB013 ). The digital watermarking is a technique used for the copyright protection of digital multimedia data BIB015 . A desired ability for these techniques is a creation of a large number of watermarks that can be embedded in multimedia data without perceptible degradation of host data. Then, the FRFT domains offer more flexibility since it has been shown that the FRFT watermarks with various angles have small correlation. Usage of two angles in the 2D FRFT offers significant possibility to hide more different watermarks in images than the standard DFT or DCT-based domains. This is illustrated with Figs. 5 and 6 taken from BIB001 . In this figure the original Lena image used as a common test example is given in Fig. 5(a) while the watermarked image is given in Fig. 5(b) . Watermark is embedded for angles a 1 ¼ a 2 ¼ 0:375p. Detection of watermarks for 1000 watermark keys is demonstrated in Fig. 6(a) where upper line corresponds to detection in the watermarked image while lower line corresponds to detection in non-watermarked image. From spread between these two lines we can conclude that watermark detection is reliable. Fig. 6(b) demonstrates a situation when a search with the proper watermark key is performed around proper angles. It can be seen that the watermark can be detected only if the angle under which the watermark is embedded is known. This is a quite important fact and it helps in increasing the number of watermarks that can be embedded within multimedia data. A practically useful scheme for the FRFT based watermarking is recently proposed in BIB014 . In particular, the impact of the noise and other errors is severely reduced on the FRFT coefficients by pre-filtering these coefficients yielding a scheme that is more robust to various attacks. Similarly, a watermarking scheme in the space/spatialfrequency domain has been proposed in BIB002 . This watermarking technique uses 2D chirp signals that are well concentrated in the joint space/spatial-frequency domain, but not in the space or spatial-frequency domain only. Therefore, this concept of watermarking provides results robust to the standard filtering, since watermarks are concentrated in the joint space/spatial-frequency domain BIB002 . Both of these techniques are closely monitored and followed by numerous researchers BIB003 BIB004 BIB005 BIB007 BIB008 BIB009 BIB010 BIB011  BIB012 . The main obstacle in further applications of these techniques is the complexity that can be reduced with various previously described fast realization strategies. In addition, the availability of the FRFT fast realizations will lead to numerous implementations of the FRFT and related transforms in multimedia.