Concealed Weapons Research Articles

Exploring Body Shape From mmW Images for Person Recognition

Due to the ability of millimeter waves (mmWs) to penetrate dielectric materials, such as plastic, polymer, and clothes, the mmW imaging technology has been widely used for the detection of concealed weapons and objects. The use of mmW images has also recently been proposed for biometric person recognition to overcome certain limitations in image acquisition at visible frequencies. This paper proposes a biometric person recognition system based on the shape information extracted from real mmW images. To this aim, we report experimental results using the mmW images with different body shape-based feature approaches, such as contour coordinates, shape contexts, Fourier descriptors, and row and column profiles. We also study various distance-based and classifier-based matching schemes. Experimental results suggest the potential of performing person recognition through mmW imaging using only shape information, a functionality that could be integrated in the security scanners deployed in airports.

Multiview three-dimensional reconstruction by millimetre-wave portable camera

Millimetre-wave imaging is a powerful non-destructive inspection technique which has become widely used in areas such as through-the-wall imaging or concealed weapon detection. Nevertheless, current systems are usually limited to either a single view point providing a limited 3D millimeter-wave model or a multiview relying on the accurate movement of a robot arm through precise positions resulting in very bulky systems. In this paper, we present a set of techniques to achieve a multiview millimetre-wave scanner. The aperture of the scanner is kept below 16 cm so it can be portable and, consequently, multiview can be achieved by simple hand movements. In addition, optical images are also acquired with a two-fold purpose: i) building a complementary 3D-model by employing Structure from Movement (SfM) techniques; ii) estimating the scanner position and poses. The proposed technology is illustrated for people screening, proving the capacity of the system to detect hidden weapons.

College Students Perceptions Toward Carrying Concealed Weapons on College Campuses

This study uses a survey of undergraduate college students at two schools in the eastern United States to investigate their attitudes toward carrying concealed weapons on campus. We found that politically conservative white men who own guns are more likely to be in favor of qualified students and faculty carrying concealed weapons on campus than politically liberal non-whites and women who do not own guns. Neither academic major nor age had a significant effect on any of our dependent variables.

Enhanced MMW and SMMW/THz imaging system performance prediction and analysis tool for concealed weapon detection and pilotage obstacle avoidance.

The U.S. Army Research Laboratory has continued to develop and enhance a millimeter-wave (MMW) and submillimeter-wave (SMMW)/terahertz (THz)-band imaging system performance prediction and analysis tool for both the detection and identification of concealed weaponry and for pilotage obstacle avoidance. The details of the MATLAB-based model that accounts for the effects of all critical sensor and display components, for the effects of atmospheric attenuation, concealment material attenuation, active illumination, target and background orientation, target and background thermal emission, and various imaging system architectures have been reported on in 2005, 2007, and 2011. This paper provides a comprehensive review of a newly enhanced MMW and SMMW/THz imaging system analysis and design tool that now includes an improved noise submodel for more accurate and reliable performance predictions, the capability to account for postcapture image contrast enhancement, and the capability to account for concealment material backscatter with active-illumination-based systems. Present plans for additional expansion of the model's predictive capabilities are also outlined.

Three-Dimensional Microwave Imaging for Concealed Weapon Detection Using Range Stacking Technique

Three-dimensional (3D) microwave imaging has been proven to be well suited for concealed weapon detection application. For the 3D image reconstruction under two-dimensional (2D) planar aperture condition, most of current imaging algorithms focus on decomposing the 3D free space Green function by exploiting the stationary phase and, consequently, the accuracy of the final imagery is obtained at a sacrifice of computational complexity due to the need of interpolation. In this paper, from an alternative viewpoint, we propose a novel interpolation-free imaging algorithm based on wavefront reconstruction theory. The algorithm is an extension of the 2D range stacking algorithm (RSA) with the advantages of low computational cost and high precision. The algorithm uses different reference signal spectrums at different range bins and then forms the target functions at desired range bin by a concise coherent summation. Several practical issues such as the propagation loss compensation, wavefront reconstruction, and aliasing mitigating are also considered. The sampling criterion and the achievable resolutions for the proposed algorithm are also derived. Finally, the proposed method is validated through extensive computer simulations and real-field experiments. The results show that accurate 3D image can be generated at a very high speed by utilizing the proposed algorithm.

Multistatic Millimeter-Wave Imaging by Multiview Portable Camera

The aim of this paper is to introduce the use of sparse multistatic arrays to reduce the number of elements in novel portable and muti-view millimiter-wave scanners. Thus, the complexity of these novel scanners is significantly reduced. Furthermore, sparsity is expected to enable embedding a conventional optical camera sensor inside the aperture of the scanner allowing a reduction of the scanner size. This camera sensor is used to build a complementary 3-D optical model as well as to estimate the millimeter-wave scanner position so that the imaging merging techniques can be applied. The approach is validated for concealed weapon detection by means of simulation as well as measurements, in which the scanner aperture is emulated by raster scan, showing a performance comparable to the case of dense arrays.

Congressional Authority to Pass Concealed Carry Reciprocity Legislation

Congress is considering passage of national concealed carry legislation requiring all states to recognize concealed weapon licenses issued by any state, rather like the way that every state recognizes driver’s licenses issued by another state. Are there any constitutional problems with such legislation? What practical problems might result? This paper seeks to answer those questions.

A fast hypervolume driven selection mechanism for many-objective optimisation problems

Abstract Solutions to real-world problems often require the simultaneous optimisation of multiple conflicting objectives. In the presence of four or more objectives, the problem is referred to as a “many-objective optimisation problem”. A problem of this category introduces many challenges, one of which is the effective and efficient selection of optimal solutions. The hypervolume indicator (or s-metric), i.e. the size of dominated objective space, is an effective selection criterion for many-objective optimisation. The indicator is used to measure the quality of a non-dominated set, and can be used to sort solutions for selection as part of the contributing hypervolume indicator. However, hypervolume based selection methods can have a very high, if not infeasible, computational cost. The present study proposes a novel hypervolume driven selection mechanism for many-objective problems, whilst maintaining a feasible computational cost. This approach, named the Hypervolume Adaptive Grid Algorithm (HAGA), uses two-phases (narrow and broad) to prevent population-wide calculation of the contributing hypervolume indicator. Instead, HAGA only calculates the contributing hypervolume indicator for grid populations, i.e. for a few solutions, which are close in proximity (in the objective space) to a candidate solution when in competition for survival. The result is a trade-off between complete accuracy in selecting the fittest individuals in regards to hypervolume quality, and a feasible computational time in many-objective space. The real-world efficiency of the proposed selection mechanism is demonstrated within the optimisation of a classifier for concealed weapon detection.

Multisensor of thermal and visual images to detect concealed weapon using harmony search image fusion approach

Perils of terror threats are a problem that can be managed by precise and competent surveillance systems. It is an imperative demand to swiftly conduct real time verification of person suspected to borne threat. Real time verification exercise involves identification of concealed weapon threat, interrogation of suspect and seizure of weapons or explosives in a covert controlled fashion. There is an urgent need for an intelligent and safe surveillance system with inbuilt sensors that can detect concealed weapons and pinpoint their location on the body without any physical contact from a standoff distance. Fused imagery of visual and infrared images is processed to identify weapons specifically. When the weapon template is matched with the suspected object using Zernike moments, the identity of the object becomes obvious, and any effort to conceal it becomes futile. In this paper, a novel approach to detect concealed weapons based on discrete wavelet transform in conjunction with dimension reduced meta-heuristic algorithm, the harmony search, and shape matching based K means SVM classification is presented. Experimental results are provided to demonstrate that the proposed hybrid approach provides superior performance.

Utopian Hopes or Dystopian Fears? Exploring the Motivational Underpinnings of Moralized Political Engagement.

People are more likely to become politically engaged (e.g., vote, engage in activism) when issues are associated with strong moral convictions. The goal of this research was to understand the underlying motivations that lead to this well-replicated effect. Specifically, to what extent is moralized political engagement motivated by proscriptive concerns (e.g., perceived harms, anticipated regret), prescriptive concerns (e.g., perceived benefits, anticipated pride), or some combination of these processes? And are the motivational pathways between moral conviction and political engagement the same or different for liberals and conservatives? Two studies (combined N = 2,069) found that regardless of political orientation, the association between moral conviction and political engagement was mediated by the perceived benefits of preferred but not the perceived harms of non-preferred policy outcomes, and by both anticipated pride and regret, findings that replicated in two contexts: legalizing same-sex marriage and allowing concealed weapons on college campuses.

A Practical Millimeter-Wave Holographic Imaging System with Tunable IF Attenuator

AbstractA practical millimeter-wave (mmw) holographic imaging system with tunable intermediate frequency (IF) attenuator has been developed. It can be used for the detection of concealed weapons at security checkpoints, especially the airport. The system is utilized to scan the passenger and detect the weapons hidden in the clothes. To reconstruct the three dimensions (3-D) image, a holographic mmw imaging algorithm based on aperture synthesis and back scattering is presented. The system is active and works at 28–33 GHz. Tunable IF attenuator is applied to compensate the intensity and phase differences between multi-channels and multi-frequencies.

The Racist Origins of California's Concealed Weapon Permit Law

California’s concealed weapon permit law has a curious history, awash in racism. This paper examines the history of why California’s constitutions (1849 and 1879) lack the right to keep and bear arms provisions common in other state constitution and shows the openly stated racist intentions behind California's three concealed weapon statutes, including the current law.

Citizen-Protectors: The Everyday Politics of Guns in an Age of Decline

Citizen-Protectors: The Everyday Politics of Guns in an Age of Decline, by Jennifer Carlson. New York: Oxford University Press, 2015. 248 pp. $29.95 cloth. ISBN: 9780199347551. It is easier for an average citizen in Dodge City or Tombstone to carry a concealed firearm in public today than it was in the nineteenth century, the heyday of the Wild West. The expansion of shall issue concealed carry laws in the United States over the past three decades represents the greatest liberalization of laws in the nation's history. Consequently, many more ordinary citizens are legally permitted to carry firearms for self-defense in public. Reasonable estimates suggest 8 to 12 million Americans have permits to carry concealed weapons nationally, with over 10 percent of the population licensed to carry in some states. Jennifer Carlson calls this a gun carry revolution, and she is right. And yet sociologists have been oddly silent about it. Carlson steps into this void with a case study of individuals who legally carry guns, either openly or concealed, in southeastern Michigan. In addition to interviews with 60 mostly white, middle-aged male carriers, Carlson did 150 hours of participant observation at shooting ranges, activist events, and training classes. In the process she also obtained a concealed carry license, carried a during her fieldwork, and became a National Rifle Association (NRA) certified firearms instructor. In the best tradition of ethnography, Carlson is a critical observer analyzing this aspect of American culture from the inside out. Carlson begins Citizen-Protectors with the stories of two individuals that illustrate the complex race, class, gender, and other social dynamics that influence carry. The first involves Corey, a white clerk at a corner store in Flint, who shoots and kills a black man in self-defense during … Language: en

An Investigation of the Weapon Focus Effect and the Confidence–Accuracy Relationship for Eyewitness Identification

Eyewitness memory can be negatively influenced by the presence of a weapon during a crime. We investigated the potential impact of weapon presence on the confidence–accuracy relationship. Additionally, we tested a concealed weapon condition, as it is common for criminals to verbally threaten a victim with a weapon, despite not showing one during a crime. In support of the weapon focus effect (WFE), correct identifications were lower, and false identifications were higher, for participants who saw the weapon. The concealed weapon did not create a WFE, even though the perpetrator attempted to draw attention to the gun in his pocket, and participants reported that he had a gun. Calibration analyses revealed that weapon presence, whether visible or concealed, did not negatively impact the confidence–accuracy relationship. In fact, participants were best calibrated when the weapon was clearly visible. We discuss implications of these findings for police and the criminal justice system.

Fast imaging method for security systems using ultrawideband radar

We propose a fast method of ultrawideband (UWB) radar imaging that can be applied to a moving target, having in mind such application as concealed weapon detection. We demonstrate the performance of the proposed method using simulations and measurements with static and moving targets. We also compare the computational complexity of the proposed method with that of a conventional method to clarify the feasibility of applying the proposed method to the intended real-time systems.

IR and Multi Scale Retinex image Enhancement for Concealed Weapon Detection

A Concealed Weapon Detection (CWD) had been developed by a large number of researchers and technologies. As a result of the weakness of the infrared images in unique altogether graphic items, infrared and MMW images become inaccurate and insufficient to obviously detectand deal withweaponry objectsin an invisible setting. This article uses Multi Scale Retinex and contrast stretching image processing enhancement techniques to improve the recognition of weapons concealed below attire. Specifically, the focus of the study is on detecting weapons and ammos by enhancing the IR pictures based on image processing techniques. Evaluation techniques were empirically proved to be able to show the enhancement percentage progress.

Two-scale image fusion of visible and infrared images using saliency detection

Military, navigation and concealed weapon detection need different imaging modalities such as visible and infrared to monitor a targeted scene. These modalities provide complementary information. For better situation awareness, complementary information of these images has to be integrated into a single image. Image fusion is the process of integrating complementary source information into a composite image. In this paper, we propose a new image fusion method based on saliency detection and two-scale image decomposition. This method is beneficial because the visual saliency extraction process introduced in this paper can highlight the saliency information of source images very well. A new weight map construction process based on visual saliency is proposed. This process is able to integrate the visually significant information of source images into the fused image. In contrast to most of the multi-scale image fusion techniques, proposed technique uses only two-scale image decomposition. So it is fast and efficient. Our method is tested on several image pairs and is evaluated qualitatively by visual inspection and quantitatively using objective fusion metrics. Outcomes of the proposed method are compared with the state-of-art multi-scale fusion techniques. Results reveal that the proposed method performance is comparable or superior to the existing methods.

Contractual Stipulations in Muslim Marriage Contract with reference to Classic Islamic Law and the Case Study of USA

This work explains the status of contractual stipulations in a marriage contract. According to majority of Jurists (Jamhur) stipulations in marriage contract are valid or invalid. Valid conditions are those which are permissible, in conformity with the requisite of the contract and strengthen its purpose whereas invalid conditions are those which are repugnant to the teachings of Shariah. Another category of stipulations is that benefits the women and is neither prohibited nor expressly permissible in Shariah. On the contrary, Hanbali school of thought allows insertion of any extrinsic condition in marriage contract. In this context, this paper attempts to locate the role and status of stipulations in marriage contract especially considering those stipulations which are beneficial to women. This work discusses classical Islamic law as expounded by the Muslim jurists; explains which stipulations are inserted in marriage contract; describes insertion of stipulations and explores the role of husband and wife within the bond of marriage contract. It concludes that under classical Islamic law conditions are either valid or invalid. However, conditions that benefit women or go against the purpose of marriage contract or empower women (only) are also prohibited by keeping in view and analyzing the teaching of Shariah as expounded by Muslim Jurists. Further, it states that in United states of America (USA) activists strive hard for empowering women by way of drafting new marriage contract or inserting new stipulations (i.e of their own choice) favoring women, which is, in fact, concealed weapon for weakening matrimonial bond and family values and against the true meaning, spirit and interpretation of Islamic law rather empowerment of women.

Near-Field Cross Section Imaging of Wideband Millimeter Wave

Near-field millimeter wave imaging has been a hot topic recent years for its importance applications in the area of anti-terrorism. The penetrating characteristic of millimeter wave is of significant importance to security, such as the concealed weapons detection, ground-penetrating radar imaging, through-barrier imaging and so on. Cross section imaging is a basic aspect for near-field millimeter wave imaging, which includes antenna array distribution and wideband signal processing. This paper utilizes back projection method in space area to realize ultra-band near- field cross section imaging. We induce two dimensional direction integral formulas to obtain the reconstruction image of the near-field imaging area, and the simulation results validate the effectiveness of this imaging algorithm.

Practical millimeter-wave holographic imaging system with good robustness

A practical millimeter-wave (MMW) holographic imaging system with good robustness is developed for the detection of concealed weapons at security checkpoints, especially at the airport. The system is used to scan the passenger and detect any weapons hidden in their clothes. To reconstruct the three dimensional image, a holographic MMW imaging algorithm based on aperture synthesis and backscattering is presented. The system is active and works at 28–33 GHz. As a practical imaging system, the robustness is analyzed in detail in terms of the peak signal-to-noise ratio.