107 research outputs found
Unsupervised Deep Hashing for Large-scale Visual Search
Learning based hashing plays a pivotal role in large-scale visual search.
However, most existing hashing algorithms tend to learn shallow models that do
not seek representative binary codes. In this paper, we propose a novel hashing
approach based on unsupervised deep learning to hierarchically transform
features into hash codes. Within the heterogeneous deep hashing framework, the
autoencoder layers with specific constraints are considered to model the
nonlinear mapping between features and binary codes. Then, a Restricted
Boltzmann Machine (RBM) layer with constraints is utilized to reduce the
dimension in the hamming space. Extensive experiments on the problem of visual
search demonstrate the competitiveness of our proposed approach compared to
state-of-the-art
An Experimental Investigation about the Integration of Facial Dynamics in Video-Based Face Recognition
Recent psychological and neural studies indicate that when people talk their changing facial expressions and head movements provide a dynamic cue for recognition. Therefore, both fixed facial features and dynamic personal characteristics are used in the human visual system (HVS) to recognize faces. However, most automatic recognition systems use only the static information as it is unclear how the dynamic cue can be integrated and exploited. The few works attempting to combine facial structure and its dynamics do not consider the relative importance of these two cues. They rather combine the two cues in an adhoc manner. But what is the relative importance of these two cues separately? Does combining them enhance systematically the recognition performance? To date, no work has extensively studied these issues. In this article, we investigate these issues by analyzing the effects of incorporating the dynamic information in video-based automatic face recognition. We consider two factors (face sequence length and image quality) and study their effects on the performance of video-based systems that attempt to use a spatio-temporal representation instead of one based on a still image. We experiment with two different databases and consider HMM (the temporal hidden Markov model) and ARMA (the auto-regressive and moving average model) as baseline methods for the spatio-temporal representation and PCA and LDA for the image-based one. The extensive experimental results show that motion information enhances also automatic recognition but not in a systematic way as in the HVS
Kinship Verification from Videos using Spatio-Temporal Texture Features and Deep Learning
Automatic kinship verification using facial images is a relatively new and
challenging research problem in computer vision. It consists in automatically
predicting whether two persons have a biological kin relation by examining
their facial attributes. While most of the existing works extract shallow
handcrafted features from still face images, we approach this problem from
spatio-temporal point of view and explore the use of both shallow texture
features and deep features for characterizing faces. Promising results,
especially those of deep features, are obtained on the benchmark UvA-NEMO Smile
database. Our extensive experiments also show the superiority of using videos
over still images, hence pointing out the important role of facial dynamics in
kinship verification. Furthermore, the fusion of the two types of features
(i.e. shallow spatio-temporal texture features and deep features) shows
significant performance improvements compared to state-of-the-art methods.Comment: 7 page
Efficient Detection of Occlusion prior to Robust Face Recognition
While there has been an enormous amount of research on face recognition under pose/illumination/expression changes and image degradations, problems caused by occlusions attracted relatively less attention. Facial occlusions, due, for example, to sunglasses, hat/cap, scarf, and beard, can significantly deteriorate performances of face recognition systems in uncontrolled environments such as video surveillance. The goal of this paper is to explore face recognition in the presence of partial occlusions, with emphasis on real-world scenarios (e.g., sunglasses and scarf). In this paper, we propose an efficient approach which consists of first analysing the presence of potential occlusion on a face and then conducting face recognition on the nonoccluded facial regions based on selective local Gabor binary patterns. Experiments demonstrate that the proposed method outperforms the state-of-the-art works including KLD-LGBPHS, S-LNMF, OA-LBP, and RSC. Furthermore, performances of the proposed approach are evaluated under illumination and extreme facial expression changes provide also significant results
Biometrics systems under spoofing attack: an evaluation methodology and lessons learned
Biometrics already form a significant component of current and emerging identification technologies. Biometrics systems aim to determine or verify the identity of an individual from their behavioral and/or biological characteristics. Despite significant progress, some biometric systems fail to meet the multitude of stringent security and robustness requirements to support their deployment in some practical scenarios. Among current concerns are vulnerabilities to spoofing?persons who masquerade as others to gain illegitimate accesses to protected data, services, or facilities. While the study of spoofing, or rather antispoofing, has attracted growing interest in recent years, the problem is far from being solved and will require far greater attention in the coming years. This tutorial article presents an introduction to spoofing and antispoofing research. It describes the vulnerabilities, presents an evaluation methodology for the assessment of spoofing and countermeasures, and outlines research priorities for the future
Complementary Countermeasures for Detecting Scenic Face Spoofing Attacks
The face recognition community has finally started paying more attention to the long-neglected problem of spoofing attacks. The number of countermeasures is gradually increasing and fairly good results have been reported on the publicly available databases. There exists no superior anti-spoofing technique due to the varying nature of attack scenarios and acquisition conditions. Therefore, it is important to find out complementary countermeasures and study how they should be combined in order to construct an easily extensible anti-spoofing framework. In this paper, we address this issue by studying fusion of motion and texture based countermeasures under several types of scenic face attacks. We provide an intuitive way to explore the fusion potential of different visual cues and show that the performance of the individual methods can be vastly improved by performing fusion at score level. The Half-Total Error Rate (HTER) of the best individual countermeasure was decreased from 11.2% to 5.1% on the Replay Attack Database. More importantly, we question the idea of using complex classification schemes in individual countermeasures, since nearly same fusion performance is obtained by replacing them with a simple linear one. In this manner, the computational efficiency and also probably the generalization ability of the resulting anti-spoofing framework are increased
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