Diffusion-based personalization brings convenience to users in text-to-image generation but it also poses risks of rights infringement and content misuse. To address this issue, researchers have proposed several proactive defense methods by adversarial attacks. However, most of these methods directly attack the noise prediction results during the fine-tuning process, overlooking the unique characteristics of diffusion-based personalization, which results in limited defense performance. Therefore, this paper summarizes the two core tasks of personalized fine-tuning as identity aggregation and identity binding, and proposes a defense method named IdentityGuard to specifically attack these two core tasks. The IdentityGuard designs a training sample decorrelation (TSD) attack and a text-image decoupling (TID) attack respectively for the two core tasks. The TSD attack disrupts the learning of common features by reducing the correlations among training samples. The TID attack targets all tokens by using the value-inverted attention map of each token as its adaptive target, aiming to suppress high-attention regions and strengthen low-attention regions. In addition, a token-level adaptive weighting strategy is designed to dynamically allocate attack weights across different tokens during fine-tuning. Experimental results demonstrate that the IdentityGuard effectively enhances proactive defense performance against diffusion-based personalization, achieving an average improvement of 22.26% in terms of Identity Score Matching (ISM) metric compared to the state-of-the-art (SOTA) methods. The source code is available at https://github.com/imagecbj/IdentityGuard.

Proactive defense against face forgery seeks to disrupt the output of forgery models by embedding imperceptible adversarial perturbations into face images to be protected. However, existing methods predominantly focus on deepfakes, often neglecting traditional image manipulations. It limits their practical applicability, as attackers may resort to traditional manipulations when deepfake attempts fail. To bridge this gap, a Dual-Forgery Proactive Defense (DFPD) method is proposed for combating both deepfakes and traditional image manipulations. For deepfake resistance, the DFPD designs a gradient-based ensemble adversarial attack that effectively disrupts outputs from multiple deepfake models. To defeat traditional manipulations, it also designs a fragile watermarking algorithm based on Invertible Neural Network (INN), enabling accurate localization of tampered regions. Furthermore, to mitigate the mutual interference between perturbation injection and watermark embedding, on the one hand, the DFPD adopts a serial pipeline starting with watermark embedding and then perturbation injection, which ensures that the injected perturbations are not displaced into residual image during INN-based embedding. On the other hand, a morphological post-processing module is introduced to eliminate adversarial noise in the tampering localization results. Extensive experiments validate the effectiveness of DFPD, demonstrating a 20.25% improvement in deepfake disruption over the best baseline in terms of PSNR and a 9.67% increase in traditional tampering localization in terms of ACC, while preserving high perceptual quality (32.75 dB PSNR).

The fast development of face synthesis technology has brought an increasing number of face synthesis services. However, when such services are misused in malicious activities, the face synthesis service providers (FSSPs) may face serious legal risks. Therefore, this letter proposes a recoverable and traceable defense watermarking method to protect FSSPs. The method designs a decoupled data hiding framework to separate two embedding tasks, where the source image and operator’s ID are inserted into the synthesized image respectively by invertible neural network and convolutional neural network. Furthermore, a facial masking strategy is employed to exclude background information of source image for enhancing the imperceptibility. The proposed method enables forensic traceability for the FSSPs to track back to the malicious users and recover the original source images, building a chain of evidence and inferring the forger’s intent after forgery. Experimental results show that compared to the existing methods, the proposed method has superior performance in source image recovery and ID extraction. In addition, the plug-and-play design of the proposed method allows for seamless integration into current face synthesis services.

Active defense is an important approach to counter speech deepfakes that threaten individuals' privacy, property, and reputation. However, the existing works in this field suffer from issues such as time-consuming and ordinary defense effectiveness. This letter proposes a Generative Adversarial Network (GAN) framework for adversarial attacks as a defense against malicious voice conversion. The proposed method uses a generator to produce adversarial perturbations and adds them to the mel-spectrogram of the target audio to craft adversarial example. In addition, in order to enhance the defense effectiveness, a spectrogram waveform conversion simulation module (SWCSM) is designed to simulate the process of reconstructing waveform from the adversarial mel-spectrogram example and re-extracting mel-spectrogram from the reconstructed waveform. Experiments on four state-of-the-art voice conversion models show that our method achieves the overall best performance among five compared methods in both white-box and black-box scenarios in terms of defense effectiveness and generation time. The source code is available at GitHub byhttps://github.com/imagecbj/Initiative-Defense-against-Voice-Conversion-through-Gen erative-Adversarial-Network.

Severe Coronavirus Disease 2019 (COVID-19) has been a global pandemic which provokes massive devastation to the society, economy, and culture since January 2020. The pandemic demonstrates the inefficiency of superannuated manual detection approaches and inspires novel approaches that detect COVID-19 by classifying chest x-ray (CXR) images with deep learning technology. Although a wide range of researches about bran-new COVID-19 detection methods that classify CXR images with centralized convolutional neural network (CNN) models have been proposed, the latency, privacy, and cost of information transmission between the data resources and the centralized data center will make the detection inefficient. Hence, in this article, a COVID-19 detection scheme via CXR images classification with a lightweight CNN model called MobileNet in edge computing is proposed to alleviate the computing pressure of centralized data center and ameliorate detection efficiency. Specifically, the general framework is introduced first to manifest the overall arrangement of the computing and information services ecosystem. Then, an unsupervised model DCGAN is employed to make up for the small scale of data set. Moreover, the implementation of the MobileNet for CXR images classification is presented at great length. The specific distribution strategy of MobileNet models is followed. The extensive evaluations of the experiments demonstrate the efficiency and accuracy of the proposed scheme for detecting COVID-19 over CXR images in edge computing.

Synthetic speech attacks bring more threats to Automatic Speaker Verification (ASV) systems, thus many synthetic speech detection (SSD) systems have been proposed to help the ASV system resist synthetic speech attacks. However, existing SSD systems still lack the generalization ability for the attacks generated by unknown synthesis algorithms. This letter proposes an end-to-end ensemble system, namely Dual-Branch Network, in which linear frequency cepstral coefficients (LFCC) and constant Q transform (CQT) are used as the input of two branches respectively. In addition, four fusion strategies are compared for the fusion of two branches to obtain an optimal one; multi-task learning and convolutional block attention module (CBAM) are introduced into the Dual-Branch Network to help the network learn the common forgery features from different forgery types of speech and enhance the representation power of learned features. Experimental results on the ASVspoof 2019 logical access (LA) dataset demonstrate that the proposed system outperforms existing state-of-the-art systems on both t-DCF and EER scores and has good generalization for unknown forgery types of synthetic speech.

Although the current generative adversarial networks (GAN)-generated face forensic detectors based on deep neural networks (DNNs) have achieved considerable performance, they are vulnerable to adversarial attacks. In this paper, an effective local perturbation generation method is proposed to expose the vulnerability of state-of-the-art forensic detectors. The main idea is to mine the fake faces’ areas of common concern in multiple-detectors’ decision-making, then generate local anti-forensic perturbations by GANs in these areas to enhance the visual quality and transferability of anti-forensic faces. Meanwhile, in order to improve the anti-forensic effect, a double- mask (soft mask and hard mask) strategy and a three-part loss (the GAN training loss, the adversarial loss consisting of ensemble classification loss and ensemble feature loss, and the regularization loss) are designed for the training of the generator. Experiments conducted on fake faces generated by StyleGAN demonstrate the proposed method’s advantage over the state-of-the-art methods in terms of anti-forensic success rate, imperceptibility, and transferability. The source code is available athttps://github.com/imagecbj/A-Local-Perturbation-Generation-Method-for-GAN-generated-Face-Anti-forensics.

In recent years, generative adversarial networks (GANs) have been widely used to generate realistic fake face images, which can easily deceive human beings. To detect these images, some methods have been proposed. However, their detection performance will be degraded greatly when the testing samples are post-processed. In this paper, some experimental studies on detecting post-processed GAN-generated face images find that (a) both the luminance component and chrominance components play an important role, and (b) the RGB and YCbCr color spaces achieve better performance than the HSV and Lab color spaces. Therefore, to enhance the robustness, both the luminance component and chrominance components of dual-color spaces (RGB and YCbCr) are considered to utilize color information effectively. In addition, the convolutional block attention module and multilayer feature aggregation module are introduced into the Xception model to enhance its feature representation power and aggregate multilayer features, respectively. Finally, a robust dual-stream network is designed by integrating dual-color spaces RGB and YCbCr and using an improved Xception model. Experimental results demonstrate that our method outperforms some existing methods, especially in its robustness against different types of post-processing operations, such as JPEG compression, Gaussian blurring, gamma correction, and median filtering.

In this paper, we improve the parallel deep neural network (DNN) scheme BusterNet for image copy-move forgery localization with source/target region distinguishment. BusterNet is based on two branches, i.e., Simi-Det and Mani-Det, and suffers from two main drawbacks: (a) it should ensure that both branches correctly locate regions; (b) the Simi-Det branch only extracts single-level and low-resolution features using VGG16 with four pooling layers. To ensure the identification of the source and target regions, we introduce two subnetworks that are constructed serially: the copy-move similarity detection network (CMSDNet) and the source/target region distinguishment network (STRDNet). Regarding the second drawback, the CMSDNet subnetwork improves Simi-Det by removing the last pooling layer in VGG16 and by introducing atrous convolution into VGG16 to preserve field-of-views of filters after the removal of the fourth pooling layer; double-level self-correlation is also considered for matching hierarchical features. Moreover, atrous spatial pyramid pooling and attention mechanism allow the capture of multiscale features and provide evidence for important information. Finally, STRDNet is designed to determine the similar regions obtained from CMSDNet directly as tampered regions and untampered regions. It determines regions at the image-level rather than at the pixel-level as made by Mani-Det of BusterNet. Experimental results on four publicly available datasets (new synthetic dataset, CASIA, CoMoFoD, and COVERAGE) demonstrate that the proposed algorithm is superior to the state-of-the-art algorithms in terms of similarity detection ability and source/target distinguishment ability.

In this study, by using the quaternion algebra, multiple‐parameter fractional quaternion Fourier transform (MPFrQFT) is proposed to generalise the conventional multiple‐parameter fractional Fourier transform (MPFrFT) to quaternion signal processing in a holistic manner. First, the new transform MPFrQFT and its inverse transform are defined. An efficient discrete implementation method of MPFrQFT is then proposed, in which the relationship between MPFrQFT and MPFrFT of four components is utilised for a quaternion signal. Finally, a new colour image encryption algorithm based on the proposed MPFrQFT and the double random phase encoding technique is proposed to evaluate the performance of the proposed MPFrQFT. Experimental results demonstrate that: (i) the computational time of the proposed implementation method is almost a half of the direct method's time; (ii) the proposed MPFrQFT‐based encryption algorithm has an overall better performance than eight compared algorithms in security test and robustness test: it is more secure than the compared frequency‐based algorithms due to the larger key space and the more sensitive key ‘transform orders’; it is also more robust than the compared spatial‐domain algorithms.

The existing quaternion-type moments (QTMs) are based on the quaternion representation (QR) of color images. However, this representation creates redundancy when using four-dimensional quaternions to represent color images with three components. In this paper, for RGB-D images, the QR is improved by combining both color and depth information, which is invariant to lighting and color variations. The improved QR fully utilizes the four-dimensional quaternion domain. The new QTMs (NQTMs) are defined using the improved QR. They are combined with the quaternion back-propagation neural network (QBPNN) for RGB-D object recognition. The experimental results demonstrate that the NQTMs outperform our previous QTMs considering only color information.

In this study, a new quaternion filter for removal of Gaussian noise in colour images is presented. It is based on the quaternion representation of colour images and the optimisation of a tight bound of the quaternion mean‐square error between the restored colour image and the original one, together with the essential idea of the non‐local means filter. The optimal weights are obtained by using the method of Lagrange multipliers. The authors' quaternion optimal weights non‐local means filter is given by the weighted means of the observed quaternion representation using the optimal weights. Experiments on commonly used images are provided to illustrate the efficiency of the proposed filter.

The derivation of moment invariants has been extensively investigated in the past decades. In this paper, we construct a set of invariants derived from Zernike moments which is simultaneously invariant to similarity transformation and to convolution with circularly symmetric point spread function (PSF). Two main contributions are provided: the theoretical framework for deriving the Zernike moments of a blurred image and the way to construct the combined geometric-blur invariants. The performance of the proposed descriptors is evaluated with various PSFs and similarity transformations. The comparison of the proposed method with the existing ones is also provided in terms of pattern recognition accuracy, template matching and robustness to noise. Experimental results show that the proposed descriptors perform on the overall better.

Moments and moment invariants are useful tool in pattern recognition and image analysis. Conventional methods to deal with color images are based on RGB decomposition or graying. In this paper, by using the theory of quaternions, we introduce a set of quaternion Zernike moments (QZMs) for color images in a holistic manner. It is shown that the QZMs can be obtained via the conventional Zernike moments of each channel. We also construct a set of combined invariants to rotation and translation (RT) using the modulus of central QZMs. Experimental results show that the proposed descriptors are more efficient than the existing ones.

Discrete orthogonal moments have been recently introduced in the field of image analysis. It was shown that they have better image representation capability than the continuous orthogonal moments. One problem concerning the use of moments as feature descriptors is the high computational cost, which may limit their application to the problems where the online computation is required. In this paper, we present a new approach for fast computation of the 2-D Tchebichef moments. By deriving some properties of Tchebichef polynomials, and using the image block representation for binary images and intensity slice representation for grayscale images, a fast algorithm is proposed for computing the moments of binary and grayscale images. The theoretical analysis shows that the computational complexity of the proposed method depends upon the number of blocks of the image, thus, it can speed up the computational efficiency as far as the number of blocks is smaller than the image size.