Biometric technology, including finger vein, fingerprint, iris, and face recognition, is widely used to enhance security in various devices. In the past decade, significant progress has been made in ...improving biometric systems, thanks to advancements in deep convolutional neural networks (DCNN) and computer vision (CV), along with large-scale training datasets. However, these systems have become targets of various attacks, with presentation attacks (PAs) being prevalent and easily executed. PAs involve displaying videos, images, or full-face masks to trick biometric systems and gain unauthorized access. Many authors are currently focusing on detecting these presentation attacks (PAD) and have developed several methods, particularly those based on deep learning (DL), which have shown superior performance compared to other techniques. This survey article focuses on manuscripts related to deep learning presentation attack detection, spoof attack detection using deep learning, and anti-spoofing deep learning methods for biometric finger vein, fingerprint, iris, and face recognition. The studies were primarily sourced from four digital research libraries: ACM, Science Direct, Springer, and IEEE Xplore. The article presents a comprehensive review of DL-based PAD systems, examining recent literature on DL-based PAD methods in finger vein, fingerprint, iris, and face detection systems. Through extensive research of the literature, recent algorithms and their solutions for relevant PAD approaches are thoroughly analyzed. Additionally, the article provides a performance analysis and highlights the most promising research findings. The discussion section addresses current issues, opportunities for advancement, and potential solutions associated with deep learning-based PAD methods. This study is valuable to various community users seeking to understand the significance of this technology and its recent applicability in the development of biometric technology for deep learning.
With the wide deployment of the face recognition systems in applications from deduplication to mobile device unlocking, security against the face spoofing attacks requires increased attention; such ...attacks can be easily launched via printed photos, video replays, and 3D masks of a face. We address the problem of face spoof detection against the print (photo) and replay (photo or video) attacks based on the analysis of image distortion (e.g., surface reflection, moiré pattern, color distortion, and shape deformation) in spoof face images (or video frames). The application domain of interest is smartphone unlock, given that the growing number of smartphones have the face unlock and mobile payment capabilities. We build an unconstrained smartphone spoof attack database (MSU USSA) containing more than 1000 subjects. Both the print and replay attacks are captured using the front and rear cameras of a Nexus 5 smartphone. We analyze the image distortion of the print and replay attacks using different: 1) intensity channels (R, G, B, and grayscale); 2) image regions (entire image, detected face, and facial component between nose and chin); and 3) feature descriptors. We develop an efficient face spoof detection system on an Android smartphone. Experimental results on the public-domain Idiap Replay-Attack, CASIA FASD, and MSU-MFSD databases, and the MSU USSA database show that the proposed approach is effective in face spoof detection for both the cross-database and intra-database testing scenarios. User studies of our Android face spoof detection system involving 20 participants show that the proposed approach works very well in real application scenarios.
We present a style-transfer based wrapper, called Universal Material Generator (UMG), to improve the generalization performance of any fingerprint spoof (presentation attack) detector against spoofs ...made from materials not seen during training. Specifically, we transfer the style (texture) characteristics between fingerprint images of known materials with the goal of synthesizing fingerprint images corresponding to unknown materials, that may occupy the space between the known materials in the deep feature space. Synthetic live fingerprint images are also added to the training dataset to supervise the CNN to learn generative-noise invariant features which discriminate between lives and spoofs. The proposed approach is shown to improve the generalization performance of two state-of-the-art spoof detectors, namely Fingerprint Spoof Buster and Slim-ResCNN, winner of the LivDet 2017 spoof detection competition. Specifically, the performance is improved from TDR of 75.24% and 73.09% to TDR of 91.78% and 90.63% @ FDR = 0.2% for Spoof Buster and Slim-ResCNN, respectively. These results are based on a large-scale dataset of 5,743 live and 4,912 spoof images fabricated using 12 different materials. In addition to generalization across different spoof materials, the proposed approach is also shown to improve the average cross-sensor spoof detection performance from 67.60% and 64.62% to 80.63% and 77.59%, for Fingerprint Spoof Buster and Slim-ResCNN, respectively, when tested on the LivDet 2017 dataset.
High-contrast gratings (HCGs) have been reported to support the spoof surface plasmon (SSP). However, HCGs have not been applied in liquid sensing in the THz range. We propose a SSP sensor based on ...HCGs with Otto prism coupling. First, the investigation results show that our structure can achieve higher sensitivity than the all-metal SSP sensor with the same geometry parameters in the liquid crystal sensing scenario. Second, the influence of the geometry parameters such as the period and the gap depth on the sensitivity is also discussed. After the necessary optimization, the sensitivity of our structure achieves the highest sensitivity up to 412.6 GHz/RIU with a resolution of 0.002 RIU around 384.5 GHz. The suggested structure demonstrates a novel method for terahertz sensing applications.
Electromagnetic (EM) skyrmions are an EM analogue of the skyrmions in condensed matter physics, offering new degrees of freedom to structure light and manipulate light–matter interactions and thus ...promising various groundbreaking applications in optics and photonics. Recently, there is a growing interest in composing EM skyrmions based on different field vectors of EM waves. Here, an EM skyrmion is realized, i.e., a spoof plasmonic skyrmion (SPS), using the electric field vectors of spoof localized surface plasmons (LSPs) in a planar microwave resonator with rotational and mirroring symmetries. The SPS is constructed by synthesizing a scalar vortex (a topological charge 0) and a polarization vortex (a topological charge 1) in the in‐plane and the out‐of‐plane component of the fields, respectively. Besides an experimental demonstration, group theory is employed and pinpoints the symmetry origin of the skyrmion. This investigation demonstrates the ubiquity of the existence of the skyrmion in any planar EM resonator holding rotational and mirroring symmetries, regardless the dimensions and the operating frequencies. This skyrmion design not only promises novel microwave applications for sensing and transferring information, but also lays down a general guideline for devising skyrmions operating over a broad range in the EM spectra.
This work reports the first realization of skyrmion in a spoof plasmonic resonator operating at microwaves and pinpoints the ubiquity of the skyrmion in any electromagnetic (EM) resonator holding rotational and mirroring symmetries. This design not only promises novel microwave applications, but also laid down a general guideline for devising skyrmions operating over a broad range of the EM spectra.
Two circularly polarized (CP) 2 × 2 array antennas based on the spoof surface plasmon polariton (SPP) and spoof localized surface plasmon (LSP) are proposed. The antenna I is fed by a feed network to ...increase the axial-ratio (AR) bandwidth. The spoof SPP and spoof LSP are introduced to increase the gain through energy localization, and the structure can suppress the cross-polarization to a certain extent and obtain a wider axial-ratio beamwidth. In addition, the electromagnetic band gap (EBG) is used to suppress surface waves to further increase the gain. The size of antenna I is 1.27λg × 1.27λg × 0.18λg. The impedance bandwidth and the AR bandwidth of antenna I are 72% (3.15-6.75 GHz) and 55% (3.97-6.72 GHz), respectively, and the peak gain is 11.11 dBi. The antenna II optimizes the distance between the two substrates according to antenna I to further increase the gain.
Metasurfaces, composed of 2-D planar arrays of sub-wavelength metallic or dielectric scatterers, have provided unprecedented freedoms in manipulating electromagnetic (EM) waves upon interfaces. The ...development of metasurface has always been closely related to antennas. On the one hand, metasurface was developed from reflect arrays/transmit arrays that are used as reflectors/lens of antennas, and most fundamental theories of metasurfaces are directly borrowed from antenna array theories; on the other hand, the development of antennas was flourished and expedited by progresses in metasurfaces. Many emerging antenna configurations have been constructed based on unique functional metasurfaces. In this article, we will review briefly the development roadmap of both metasurfaces and metasurface-based antennas, including antenna-inspired metasurfaces, metasurface-assisted antennas, and metasurface antennas. In particular, the recent fusion of metasurface and antenna as metantenna will bring significant impacts on methodologies of functional metasurface, antenna design, and radio-frequency device miniaturization.
Driven by the miniaturization of integrated electronics, research on spoof plasmonic circuits has recently aroused widespread interest. On the other hand, nonreciprocal devices, such as isolators and ...circulators, are key components of integrated electronic systems. However, bulky magnets required to realize isolation and circulation prevent the application of traditional nonreciprocal technologies to integrated systems. Here, parametric amplification is explored to achieve magnetic‐free plasmonic isolation, and an ultrathin reconfigurable spoof plasmonic isolator is realized experimentally. In this isolation system, the forward signal amplified by a spoof plasmonic parametric amplifier is coupled to a second linear plasmonic waveguide via a spoof localized surface plasmon resonator, whereas the transmission from the inverse direction is prohibited, giving rise to a measured isolation ratio of up to 20 dB. By tuning the nonlinear phase‐matching condition through external bias voltage, multifrequency isolation of spoof surface plasmon polariton (SSPP) signals is also realized experimentally. This work demonstrates the possibility of producing miniaturized and low‐cost nonreciprocal SSPP devices, holding great promise for applications in nonmagnetic information processing and radar detection.
A reconfigurable nonmagnetic isolator with parametric amplification is demonstrated experimentally on an ultrathin planar spoof plasmonic platform. They envision this work could establish a foundation for developing magnetic‐free nonreciprocal isolation spoof surface plasmon polariton devices suitable for on‐chip integration with microwave circuits, with the potentials to revolutionize applications in communication and radar systems.
Face anti-spoof systems are needed in facial recognition systems to ward off attacks that present fake faces in front of the camera or image capture sensor (presentation attack). To build the system, ...a data set is needed to build a classification model that distinguishes the authenticity of the face of the input image received by the system. In the past decade anti-face spoof research has produced many data sets that are public, but often researchers need time to build or use the right public data sets that are used to build facial anti-spoof models. This article conducts a literature study of public data sets using a systematic literature review method to find out the types of attacks that appear on the facial anti-spoof system, the development process, evolution, and availability of facial anti-spoof data sets. From the search and selection results based on the specified criteria, there were 42 primary research manuscripts in the period 2010 to 2021. The results of the literature study found that there were three trends in the development of anti-spoof facial data sets, namely, 1) data sets with a very large number, 2) datasets with different types of facial samples, and 3) datasets constructed with various devices and sensors. These various public data sets can be accessed freely but with special rules such as agreeing to an end user license agreement document from the researcher or the institution that owns the data set. However, there are also datasets that cannot be accessed due to invalid URLs or due to special rules from the cloud storage service provider where the datasets are stored.
In this article, a spoof surface plasmon (SSP) ring resonator to generate dynamically reconfigurable vortex beams is proposed. According to the phase constant control of the SSP and the harmonic ...radiation principle, the tunable cylindrical vector vortex beams (VVBs) with different topological charges can be obtained. The tunable system that operates by electronic control would utilize varactors to change the wavenumber of SPP on the ring resonator and realize the reconfigurable VVBs modes at a fixed frequency. All VVBs have excellent orbital angular momentum (OAM) purity (above 90%). Interestingly, the antenna also simultaneously radiates the scalar vortex beams with tunable OAM modes. Both numerical simulations and experimental characterizations confirm the theoretical predictions. Because the designed antenna has the advantages of simple feeding network, easy bias circuit, as well as miniaturization and integration compatibility, we anticipate that the antenna will enable a wide range of applications for future wireless communication and imaging technologies.
