Generalized Face Liveness Detection via De-spoofing Face Generator

Previous Face Anti-spoofing (FAS) works face the challenge of generalizing in unseen domains. One of the major problems is that most existing FAS datasets are relatively small and lack data diversity. However, we find that there are numerous real faces that can be easily achieved under various conditions, which are neglected by previous FAS works. In this paper, we conduct an Anomalous cue Guided FAS (AG-FAS) method, which leverages real faces for improving model generalization via a De-spoofing Face Generator (DFG). Specifically, the DFG trained only on the real faces gains the knowledge of what a real face should be like and can generate a "real" version of the face corresponding to any given input face. The difference between the generated "real" face and the input face can provide an anomalous cue for the downstream FAS task. We then propose an Anomalous cue Guided FAS feature extraction Network (AG-Net) to further improve the FAS feature generalization via a cross-attention transformer. Extensive experiments on a total of nine public datasets show our method achieves state-of-the-art results under cross-domain evaluations with unseen scenarios and unknown presentation attacks.Comment: v

Face Anti-Spoofing and Deep Learning Based Unsupervised Image Recognition Systems

One of the main problems of a supervised deep learning approach is that it requires large amounts of labeled training data, which are not always easily available. This PhD dissertation addresses the above-mentioned problem by using a novel unsupervised deep learning face verification system called UFace, that does not require labeled training data as it automatically, in an unsupervised way, generates training data from even a relatively small size of data. The method starts by selecting, in unsupervised way, k-most similar and k-most dissimilar images for a given face image. Moreover, this PhD dissertation proposes a new loss function to make it work with the proposed method. Specifically, the method computes loss function k times for both similar and dissimilar images for each input image in order to increase the discriminative power of feature vectors to learn the inter-class and intra-class face variability. The training is carried out based on the similar and dissimilar input face image vector rather than the same training input face image vector in order to extract face embeddings. The UFace is evaluated on four benchmark face verification datasets: Labeled Faces in the Wild dataset (LFW), YouTube Faces dataset (YTF), Cross-age LFW (CALFW) and Celebrities in Frontal Profile in the Wild (CFP-FP) datasets. The results show that we gain an accuracy of 99.40\%, 96.04\%, 95.12\% and 97.89\% respectively. The achieved results, despite being unsupervised, is on par to a similar but fully supervised methods. Another, related to face verification, area of research is on face anti-spoofing systems. State-of-the-art face anti-spoofing systems use either deep learning, or manually extracted image quality features. However, many of the existing image quality features used in face anti-spoofing systems are not well discriminating spoofed and genuine faces. Additionally, State-of-the-art face anti-spoofing systems that use deep learning approaches do not generalize well. Thus, to address the above problem, this PhD dissertation proposes hybrid face anti-spoofing system that considers the best from image quality feature and deep learning approaches. This work selects and proposes a set of seven novel no-reference image quality features measurement, that discriminate well between spoofed and genuine faces, to complement the deep learning approach. It then, proposes two approaches: In the first approach, the scores from the image quality features are fused with the deep learning classifier scores in a weighted fashion. The combined scores are used to determine whether a given input face image is genuine or spoofed. In the second approach, the image quality features are concatenated with the deep learning features. Then, the concatenated features vector is fed to the classifier to improve the performance and generalization of anti-spoofing system. Extensive evaluations are conducted to evaluate their performance on five benchmark face anti-spoofing datasets: Replay-Attack, CASIA-MFSD, MSU-MFSD, OULU-NPU and SiW. Experiments on these datasets show that it gives better results than several of the state-of-the-art anti-spoofing systems in many scenarios

Enhanced Deep Learning Architectures for Face Liveness Detection for Static and Video Sequences

The major contribution of this research is the development of deep architectures for face liveness detection on a static image as well as video sequences that use a combination of texture analysis and deep Convolutional Neural Network (CNN) to classify the captured image or video as real or fake. Face recognition is a popular and efficient form of biometric authentication used in many software applications. One drawback of this technique is that, it is prone to face spoofing attacks, where an impostor can gain access to the system by presenting a photograph or recorded video of a valid user to the sensor. Thus, face liveness detection is a critical preprocessing step in face recognition authentication systems. The first part of our research was on face liveness detection on a static image, where we applied nonlinear diffusion based on an additive operator splitting scheme and a tri-diagonal matrix block-solver algorithm to the image, which enhances the edges and surface texture in the real image. The diffused image was then fed to a deep CNN to identify the complex and deep features for classification. We obtained high accuracy on the NUAA Photograph Impostor dataset using one of our enhanced architectures. In the second part of our research, we developed an end-to-end real-time solution for face liveness detection on static images, where instead of using a separate preprocessing step for diffusing the images, we used a combined architecture where the diffusion process and CNN were implemented in a single step. This integrated approach gave promising results with two different architectures, on the Replay-Attack and Replay-Mobile datasets. We also developed a novel deep architecture for face liveness detection on video frames that uses the diffusion of images followed by a deep CNN and Long Short-Term Memory (LSTM) to classify the video sequence as real or fake. Performance evaluation of our architecture on the Replay-Attack and Replay-Mobile datasets gave very competitive results. We performed liveness detection on video sequences using diffusion and the Two-Stream Inflated 3D ConvNet (I3D) architecture, and our experiments on the Replay-Attack and Replay-Mobile datasets gave very good results