Hidden Objects Research Articles

Automated microwave monitoring of hidden objects for strategic and security applications

An automated microwave technique for the monitoring of hidden objects for strategic applications has been presented. The proposed approach is quite novel as it implements and integrates the time-domain method in free-space with the indigenously developed automated scanning setup to obtain the dielectric profile of hidden objects in standard sand or behind the concrete structure. The existing imaging methods for concealed media cannot reveal detailed information of objects with restrictions to access the other side of the test media. The overall approach is implemented by measuring the S-parameters of the test region containing the hidden objects in the wide frequency range of 2-10 GHz using the horn-lens antenna and the network analyzer. The S-parameters are transformed into the equivalent time-domain using the standard IFFT algorithm to retrieve the test region's 2D microwave image and the approximate size of concealed objects, which helps in situations such as through-the-wall imaging, and landmine detection.

Maximizing the Efficiency of Active Case Finding for SARS-CoV-2 Using Bandit Algorithms.

Even as vaccination for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) expands in the United States, cases will linger among unvaccinated individuals for at least the next year, allowing the spread of the coronavirus to continue in communities across the country. Detecting these infections, particularly asymptomatic ones, is critical to stemming further transmission of the virus in the months ahead. This will require active surveillance efforts in which these undetected cases are proactively sought out rather than waiting for individuals to present to testing sites for diagnosis. However, finding these pockets of asymptomatic cases (i.e., hotspots) is akin to searching for needles in a haystack as choosing where and when to test within communities is hampered by a lack of epidemiological information to guide decision makers' allocation of these resources. Making sequential decisions with partial information is a classic problem in decision science, the explore v. exploit dilemma. Using methods-bandit algorithms-similar to those used to search for other kinds of lost or hidden objects, from downed aircraft or underground oil deposits, we can address the explore v. exploit tradeoff facing active surveillance efforts and optimize the deployment of mobile testing resources to maximize the yield of new SARS-CoV-2 diagnoses. These bandit algorithms can be implemented easily as a guide to active case finding for SARS-CoV-2. A simple Thompson sampling algorithm and an extension of it to integrate spatial correlation in the data are now embedded in a fully functional prototype of a web app to allow policymakers to use either of these algorithms to target SARS-CoV-2 testing. In this instance, potential testing locations were identified by using mobility data from UberMedia to target high-frequency venues in Columbus, Ohio, as part of a planned feasibility study of the algorithms in the field. However, it is easily adaptable to other jurisdictions, requiring only a set of candidate test locations with point-to-point distances between all locations, whether or not mobility data are integrated into decision making in choosing places to test.

Tecno-animismo ou a existência mágica de objetos técnicos

If, on the one hand, the classic notion of artefact presupposes inert objects and a reliability between the user and the uses that can be extracted from the objects, on the other hand, it is recognized a suspicion that technical objects and their operative schemes, the machines and the “artificial” solutions contain in themselves an inauthentic and adulterating nature, a power of cunning and trickery capable of emancipate and process in autonomous forms, regardless of the uses and apprehensions that humans, their operators, may make. The western imaginary of technics would thus have been constituted under presuppositions that, together with the formal laws of mechanics or the cold mathematics that governs any grammar of codes, projected a animistic and a magical dimension in all the artificiality that allowed to manipulate the original productivity of nature. With the emergence of digital technologies and the general informatization of artefacts, this dimension took shape in what Philip K. Dick would consider to be a techno-animism tendency and that ubiquitous computing and internet of things would materialize in the era of so-called cognitive capitalism. In this paper, we seek to approach techno-animism as a speculative aesthetics that, by projecting a life into technical objects, inscribes in them an alterity and a strangeness that could enhance other perspectives beyond the usual uses and relationships that we take for granted and that hide objects, as well as the political or commercial strategies that mobilize them. Enchanting technical objects is, on the one hand, creating a possibility to suspend them from their instrumental flows and, on the other, installing a weird or magical realism that disturbs the articulations of a mere and exclusively human reality.

Numerical Modeling of Nondestructive Testing of Various Conductive Objects inside Metal Enclosures Using ELF/VLF Magnetic Fields

Nondestructive evaluation of various conductive objects through metal enclosures is investigated by using ELF/VLF magnetic induction fields in detailed simulations. ELF/VLF magnetic fields (<30 kHz) have a unique ability to penetrate highly conductive or permeable shields. Using a magnetic dipole source antenna, objects hidden inside a metal enclosure are imaged via examining distortions to the field outside the enclosure. The field distortion is parametrically studied by varying the size, conductivity, and permeability of the hidden objects. Furthermore, the importance of the conductivity of the enclosure itself is investigated using both low (106 S/m) and high (108 S/m) conductivity metallic shields. It is shown that the responses are quite sensitive to the object and shield parameters; both qualitative and quantitative properties of the field distortions are described in detail. The simulation results suggest that properties of hidden conductive or permeable objects, over a relatively wide range of parameters (both geometry and material), can be inferred nondestructively using ELF/VLF magnetic induction fields.

A Magnetic Field Camera for Real-Time Subsurface Imaging Applications

We have constructed an imaging device that is capable of showing the spatio-temporal distribution of magnetic flux density in real-time. The device employs a set of AMR (anisotropic magneto-resistance) three-axis magnetometers, which are arranged into a two-dimensional sensor array. All of the magnetic field values measured by the array are collected by a microcontroller, which pre-processes and sends the data to a PDU (processing and display unit) implemented on a smartphone/tablet or a computer. The interpolation algorithm and display software in the PDU present the field as a high-resolution video; thus, the device works as a magnetic field camera. In the experiments, we employ the camera to map the field distribution of the distorted ambient magnetic field caused by a hidden object. The obtained image of field shows both the position and shape of the object. We also demonstrate the capability of the device to image a loaded power-line cable carrying a 50 Hz alternating current.

Sensory Ecology & Evolution

From a young age, children are fascinated by hide-and-seek games. These visual acuity games strengthen observational skills while increasing a competitive spirit to find a fellow playmate or a hidden object in an image. Unknowingly, children are using ecological and evolutionary principles of camouflage, mimicry, and adaptation when playing these classic games.The website Sensory Ecology & Evolution (https://www.sensoryecology.com/games), curated by the Centre for Ecology & Conservation at the University of Exeter in the United Kingdom, utilizes citizen science games to develop new tools to study visual observations in reference to organism coloration in a variety of realistic habitats. Human “predators” participate in computer experiments to contribute to an understanding of camouflage, disruptive coloration, and distractive markings. The center’s research also focuses on laboratory and field data with the aim of understanding animal vision, with applications to ecology, evolution, and animal behavior. Organisms, ranging from beetles to moths to crabs to frogs to hares to birds’ eggs to plants, are highlighted in the various citizen science games that will be sure to test your students’ visual acuity and be a perfect springboard for discussion around natural selection, adaptation, camouflage, and animal behavior, to name a few.When selecting a game for classroom or individual use, teachers should play the game first to test their own visual acuity. The habitats and various backgrounds are real images recorded and curated directly from the natural environments of the organisms. By clicking “start,” the participant agrees to have their data included in the larger research study. General instructions are included in the beginning of each game, with an example of the organism with size reference to be located. Silhouettes with various designs, ranging from solid colors to stripes to polka dots to more realistic-looking organisms such as frogs or herbs, are also featured in the games.Most of the games have a timer and bar count across the bottom of the screen where the observer is tasked with finding a particular number of organisms within a set time limit. Each game also asks whether the observer has played the game before. When one’s score and visual spotting percentage is revealed at the end of the game, it becomes a springboard for friendly competition with students. Most high school students would immediately jump at the chance to compete with me and with one another. The game provides a leaderboard at the end for quick identification, but an individual class leaderboard could also be easily generated as a class. Once the students recognize the organism’s shape and possible coloration and patterns, they will become invested in finding the organisms in the real images of habitats.The games can be utilized to introduce and reinforce observational skills or prior to evolution or ecology laboratories. For example, “Find the Camouflaged Moth” uses a simple triangular moth shape to see whether coloration or a particular pattern can evade predators more successfully. “Evolving Bugs” employs a beetle image to study whether a particular pattern optimizes camouflage. When introducing variation in a population, natural selection, and differential survival and reproduction, these games are perfect and contribute to a larger research endeavor.One of the highlights of these citizen science games is the ability to differentiate them for all grade levels. For example, “Spot the Hares” or “Frog Finder” can be utilized by lower elementary school students as they spot the hares or frogs among the field sites. Younger students can test their identification speed with a race against the clock and a chance to obtain a high score on the leaderboard, whereas an older student may connect the ability to spot the hare to climate change that could alter the snowy landscape over time. Furthermore, students can access the official publications and connect the games to the field studies, which enables the games to evolve into another educational opportunity for reading and evaluating scientific literature.When one thinks of camouflage, plants are not usually considered. However, one of the games, “Spot the Plant,” focuses on plant evolution of fritillaries used as medicinal plants in southwest China. This game is unique, in that one can play the game as a human or a yak. It is interesting to see how the selective pressure varies when the predators’ vision differs.As children explore the natural world, the classic hide-and-seek games can demonstrate the universal biological importance of observation, camouflage, and visual acuity. Biological principles and NGSS standards of natural selection, adaptation, environmental conditions, and biodiversity are evident in these citizen science games through Sensory Ecology & Evolution. A fun, competitive childhood game evolves into a research study worthy of further exploration.

Optical information hiding with non-mechanical ptychography encoding

Since the ptychographic encoding can transform the secret information into series of diffractive patterns optically, it achieves the high security for information hiding. However, traditional ptychographic encoding requires the mechanical movements of the illuminated probe or the hidden object, which accumulates the errors greatly reducing the decoding quality. The errors have been reduced with the way of the single-shot ptychographic encoding, while its reliability and the decoding quality are still unideal. To solve these problems, we propose a non-mechanical ptychography to hide optical information for the first time. The core of this method includes both the non-mechanical ptychographic encoding (NPE) via a spatial light modulator and the decoding algorithm constrained with the phase-only quick respond code (PQR). NPE completely eliminates the errors arising from the ptychographic scanning, and the PQR-constrained decoding algorithm enables the high-quality information extracted from even only a few embedded diffractive patterns. The optical experiments verify that the method can achieve satisfactory robustness performance with the high repeatability, real-time encoding speed and the excellent information fidelity.

Fast and Resilient Manipulation Planning for Object Retrieval in Cluttered and Confined Environments

In this article, we present a task and motion planning method for retrieving a target object from clutter using a robotic manipulator. We consider dense and cluttered environments where some objects must be removed in order to retrieve the target without collisions. To ensure a successful execution, the interplay between task planning ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">what to remove in what order</i> ) and motion planning ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">how to remove</i> ) is crucial. Thus, the task and motion planning approach combining a symbolic task planner and a geometric motion planner becomes one of the major paradigms in manipulation planning. However, motion planning in dense clutter often leads to frequent failures, so repetitive task replanning is inevitable. Although symbolic task planners are general and domain-independent, they do not scale; so we need an efficient task planner specialized for dense clutter for fast completion of tasks. We propose a polynomial-time task planner for object manipulation in clutter that can be combined with any motion planner. We aim to optimize the number of pick-and-place actions which often determines the efficiency of object manipulation tasks. We consider common situations that could occur in clutter: 1) all object locations are known, 2) some hidden objects are revealed while relocating some front objects, and 3) the target is hidden until some objects are removed. Our method is shown to reduce the number of pick-and-place actions compared to baseline methods (e.g., at least 28.0% of reduction in a known static environment with 20 objects). We also deploy the proposed method to two physical robots with vision systems to show that our method can solve real-world problems.

Non-closed acoustic cloaking devices enabled by sequential-step linear coordinate transformations

Hitherto acoustic cloaking devices, which conceal objects externally, depend on objects' characteristics. Despite previous works, we design cloaking devices placed adjacent to an arbitrary object and make it invisible without the need to make it enclosed. Applying sequential linear coordinate transformations leads to a non-closed acoustic cloak with homogeneous materials, creating an open invisible region. Firstly, we propose to design a non-closed carpet cloak to conceal objects on a reflecting plane. Numerical simulations verify the cloaking effect, which is completely independent of the geometry and material properties of the hidden object. Moreover, we extend this idea to achieve a directional acoustic cloak with homogeneous materials that can render arbitrary objects in free space invisible to incident radiation. To demonstrate the feasibility of the realization, a non-resonant meta-atom is utilized which dramatically facilitated the physical realization of our design. Due to the simple acoustic constitutive parameters of the presented structures, this work paves the way toward realization of non-closed acoustic devices, which could find applications in airborne sound manipulation and underwater demands.

Evaluation of Visuospatial Short-term and Working Memory from the First to Second Year of Life: A Novel Task

ABSTRACT The prototypical tasks for assessing visuospatial memory in infancy are based on the search for a hidden object in two locations. Fewer studies include more locations, delayed responses nor changes in the object’s position. Our aim was to assess the visuospatial short-term and working memory in 12, 15, 18 and 22-month-old children (N = 65). Assessment included our experimental task, a working memory task and a cognitive developmental scale. Short-term and working memory abilities increased markedly at 22 months compared to younger ages and the performance of the children in our experimental task is related to other tasks previously used.

Broadband scattering imaging technology based on common-mode rejection of polarization characteristic

&lt;sec&gt;Owing to the inhomogeneity of the refractive index inside the sample (e.g. biological tissue) or on the surface of the sample(e.g. ground glass), light will be strongly scattered when it propagates through the sample. Therefore, we can hardly obtain the information about the objects behind the scattering medium, except for only a complex speckle pattern. To date, many approaches to realize focusing and imaging through scattering medium have been put forward. The traditional method mainly utilizes ballistic photons for imaging through scattering medium. Since the ballistic light is attenuated exponentially with the increase of depth of propagation in the scattering medium, the reconstruction from the speckle formed by scattered light is more conducive to practicability such as deep biomedical imaging. Typically, the wavefront shaping, optical transmission matrix and speckle correlation techniques which can successfully recover hidden object from the speckle, are valuable in biomedical imaging field. However, both optical transmission matrix and wavefront shaping rely on the coherence of light waves. The physical model of speckle correlation imaging is limited by the similarity of the point spread function of the imaging system. Thus, it is restrictive to achieve imaging through random scattering medium with broadband light illumination by using the current techniques.&lt;/sec&gt;&lt;sec&gt;In this paper, we present a broadband scattering imaging method based on common-mode rejection of polarization characteristic. In order to solve the problem that current scattering imaging methods are limited by the spectral width of the light source illumination, the polarization characteristic of the speckle field is explored in depth. We qualitatively analyze the difference in polarization information between the hidden object and the background noise in the speckle field. Notably, owing to the differences among autocorrelation functions of the speckle field intensity with different rotate angles of polarization, we can obtain two images where the object information contained in the speckle field and the background noise are dominant. Specifically, two speckle patterns are selected according to the maximum value and minimum value of the peak-to-correlation energy of the different speckles’ intensity autocorrelation. Afterwards, the serious background noise caused by the broadband light illumination is significantly suppressed by using polarization speckle difference imaging, and then the hidden object is reconstructed, with basic phase retrieval algorithm combined.&lt;/sec&gt;&lt;sec&gt;Comparison with conventional speckle correlation imaging technique, the value of peak signal-to-noise ratio and structural similarity index of reconstructions through using the proposed method are improved significantly, and the fitting curves are stabilized. Emphatically, the background noise item is physically handled by developing a novel physical imaging model. Furthermore, the proposed method is highly efficient and universal to recover different types of the hidden objects with better quality under broadband light illumination. Therefore, the proposed method has more potential applications in scattering imaging and biomedical imaging.&lt;/sec&gt;

Designing an Escape Room to Increase Pharmacy Preceptor Knowledge of the Pharmacists’ Patient Care Process

Objective. To design and assess the use of an escape room for pharmacy preceptor development.Methods. An escape room for preceptor development that focused on the Pharmacists' Patient Care Process (PPCP), preceptor resources, and the school of pharmacy's mission and vision was created. Teams had to solve digital and practical puzzles to escape a pharmacy. The team to correctly solve all the puzzles the fastest was considered to have escaped the pharmacy. Escape room puzzles included digital locks, cipher wheels, a rebus puzzle, riddle, hidden object, and other puzzles. Preceptor's knowledge of the PPCP and perceptions of the game were evaluated using a pre- and post-activity test and survey.Results. Fifteen preceptors with a variety of practice sites and precepting experience participated in a matched pre-and post-activity survey. Preceptor knowledge of the order of the PPCP improved, with nine (60%) preceptors answering correctly before participating in the activity vs 13 (87%) after. However, the preceptors were less likely to correctly answer the type of approach the PPCP uses after completing the escape room activity, with 14 (93%) answering correctly before vs 10 (67%) after. Participants' perceptions of the game were positive and all preceptors agreed or strongly agreed that they would recommend participating in this activity to another preceptor.Conclusion. A preceptor development escape room was viewed positively by preceptors. Future research should focus on digital-only escape rooms for preceptors to increase availability and participation.

Determination of relative position of antenna system and RGB-D sensor in combined microwave imaging system

Microwave imaging technique allows obtaining images of hidden objects in structures and media using microwaves. This technique has various applications such as: nondestructive testing, medical imaging, concealed weapon detection, through-the-wall imaging, etc. Obtaining radar images in these applications is based on processing phase and amplitude of the reflected signal recorded over an aperture (a microwave hologram). Recently, systems began to appear in which the radar part is supplemented by an RGB-D sensor, which allows to obtain new capabilities. For example, there is the a microwave screening system architecture in which inverse synthetic aperture is formed by the natural motion of the subject in the vicinity of a stationary linear antenna array. The microwave system is complemented with an synchronous RGB-D video sensor which captures the trajectory of the moving subject in 3D and allows coherent processing of the radar signal. Another system detects objects buried under irregular surface and uses RGB-D sensor for capturing the surface relief for suppressing reflection of the sounding signal from the surface. Calibration between a radar and an RGB-D sensor is an essential process for microwave and optical data fusion. This article presents a novel approach for calibration, using a planar calibration target which is made of radiotransparent material (such a foam plastic sheet) with square marker and six small metal balls embedded in target surface and representing point objects. The proposed method exploits 3D-3D correspondences between coordinates of point objects in two coordinate systems associated to the sensor and to the radar. One points set is extracted from optical data, using marked corners of the target as a base points. Second points set is obtained from microwave data as local maxima of 3D volume of data reconstructed from one-frequency microwave hologram. Computer modeling were performed using Autodesk 3ds Max software by which models of all components of the system were built and the optical image from the sensor was modeled. Test experiments were carried out using a measurement system composed of the following components: a compact vector network analyzer (VNA), two mechanical scanners with stepper motors, one transmitting and one receiving horn antennas, mounted on the VNA, an RGB-D sensor, a microcontroller board, and a computer. The high accuracy of the method is confirmed both by computer modeling and physical experiment. The accuracy of determination of relative position between the radar and the sensor is about one fifth of the signal wavelength used.

Influence of multiple reflections in simulation of scattering electromagnetic wave by objects of complex shape

Microwave imaging technique allows obtaining images of hidden objects in structures and media using microwaves. This technique has various applications such as: nondestructive testing, medical imaging, concealed weapon detection, through-the-wall imaging, etc. Obtaining radar images in these applications is based on processing phase and amplitude of the reflected signal recorded over an aperture (a microwave hologram). To design and evaluate the effectiveness of modern radars, to test the developed reconstruction algorithms, microwave holograms of various objects obtained under different conditions are required. Obtaining microwave holograms by experimental methods is associated with measuring the scattering fields of real objects. Such experiments are rather laborious and expensive. Therefore, the problem of modeling the processes of scattering of electromagnetic waves by the objects of study is very important. Since the implementation of rigorous methods for solving the scattering problem is associated with large computational costs, it is sometimes advisable to use various simplifications and assumptions to analyze scattering fields on objects of complex spatial configuration. One of these methods is the physical optics method, which is a very common method for calculating fields scattered from objects of various shapes. The physical meaning of the approximation of the physical optics approach is that the field on the surface of the scattering object is taken to be equal to the field in the absence of the object. In other words, multiple reflections of an electromagnetic wave between different parts of the object are not taken into account. The aim of this work is to study the influence of the effects of re-reflection of an electromagnetic wave and to reveal the dependence of the accuracy of the calculation of the scattered field, performed by the physical optics method, on the shape of scattering objects. A comparison of microwave holograms obtained by the physical optics method with the results of calculations using the computational electromagnetic software product FEKO is carried out. It was found that for objects consisting of separate elements, spatially separated in a plane parallel to the registering plane, rereflections have the strongest effect on the recorded microwave hologram of an object if a distance between the elements equal to about 65% of the wavelength. In general, for such objects, the degree of influence of multiple reflections is small, and they can be ignored when modeling microwave holograms. For objects consisting of separate elements spatially spaced in a direction perpendicular to the registering plane, the influence of multiple reflections is approximately five times greater than for the previous case. The greatest effect is observed when the distance between the elements is equal to 30% of the wavelength. Under such conditions, ignoring re-reflections when modeling microwave holograms can lead to incorrect results when reconstructing them. When modeling scattering by spatially extended solid objects, the degree of influence of re-reflections depends on the shape of the object: if the side of the object oriented to the registering plane of the microwave hologram is convex, then the influence is minimal, and if it is concave, re-reflections must be taken into account.

Formation of initial projection data in reflection tomography in the implementation of technical vision

The known principles of active monostatic radar are based on the effect of radio wave scattering on objects located on the path of the probing signal, and the subsequent registration of a part of the wave reflected in the direction of the emitter. However, within the framework of this study, it is of interest to register objects that do not return a reflected radio echo towards the emitter. When fixing the position of an object, it is assumed that there is a possible absence of an echo signal characteristic of classical active radar with a passive response. The absence of a characteristic echo signal does not exclude its return as a result of repeated reflection inside the scene, including along other routes and from other objects. Purpose – within the framework of the implementation of technical vision in the course of tomographic observation of a complex radar scene that solves the problems of multidimensional reconstruction, a stochastic model based on the principles of tomography describing the subject area of a complex radar scene is developed. In the indicated relevance of the development of methods for radar detection of hidden objects inaccessible for registration by classical methods, a variant of using tomographic observation of a complex radar scene is proposed. In connection with the admitted lowangle and the emerging problems of an unambiguous deterministic definition, a description of the subject area of the scene from a stochastic position is proposed. In the proposed tomographic method, in conditions of limited initial data, when a deterministic approach to the reconstruction of the radar scene is not possible, an acceptable solution is sought in the stochastic description. At a given value by sampling the space, determined by the hexagonal lattice cell, the scene reconstruction is carried out by selecting and analyzing the echo signal trajectories from the possible set of proposed ones. The decision on the choice of one or another proposed trajectory and its transfer to the category of a possible solution is carried out on the basis of a preliminary calculation of the characteristics of the stochastic description.

MLO: Multi Leader Optimizer

Optimization is a topic that has always been discussed in all different fields of science. One of the most effective techniques for solving such problems is optimization algorithms. In this paper, a new optimizer called Multi-Leader optimizer (MLO) is developed in which multiple leaders guide members of the population towards the optimal answer. MLO is mathematically modelled based on the process of advancing members of the population and following the leaders. MLO performance in optimization is examined on twenty-three standard objective functions. The results of this optimization are compared with the results of the other eight existing optimization algorithms including Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Teaching-Learning-Based Optimization (TLBO), Gray Wolf Optimizer (GWO), Grasshopper Optimization Algorithm (GOA), Emperor Penguin Optimizer (EPO), Shell Game Optimization (SGO), and Hide Objects Game Optimization (HOGO). Based on the analysis of the simulation results on unimodal test functions to evaluate exploitation ability and multimodal test functions in order to evaluate exploration ability, it has been determined that MLO has a higher ability to solve optimization problems than existing optimization algorithms.

Learned feature embeddings for non-line-of-sight imaging and recognition

Objects obscured by occluders are considered lost in the images acquired by conventional camera systems, prohibiting both visualization and understanding of such hidden objects. Non-line-of-sight methods (NLOS) aim at recovering information about hidden scenes, which could help make medical imaging less invasive, improve the safety of autonomous vehicles, and potentially enable capturing unprecedented high-definition RGB-D data sets that include geometry beyond the directly visible parts. Recent NLOS methods have demonstrated scene recovery from time-resolved pulse-illuminated measurements encoding occluded objects as faint indirect reflections. Unfortunately, these systems are fundamentally limited by the quartic intensity fall-off for diffuse scenes. With laser illumination limited by eye-safety limits, recovery algorithms must tackle this challenge by incorporating scene priors. However, existing NLOS reconstruction algorithms do not facilitate learning scene priors. Even if they did, datasets that allow for such supervision do not exist, and successful encoder-decoder networks and generative adversarial networks fail for real-world NLOS data. In this work, we close this gap by learning hidden scene feature representations tailored to both reconstruction and recognition tasks such as classification or object detection, while still relying on physical models at the feature level. We overcome the lack of real training data with a generalizable architecture that can be trained in simulation. We learn the differentiable scene representation jointly with the reconstruction task using a differentiable transient renderer in the objective, and demonstrate that it generalizes to unseen classes and unseen real-world scenes , unlike existing encoder-decoder architectures and generative adversarial networks. The proposed method allows for end-to-end training for different NLOS tasks , such as image reconstruction, classification, and object detection, while being memory-efficient and running at real-time rates. We demonstrate hidden view synthesis, RGB-D reconstruction, classification, and object detection in the hidden scene in an end-to-end fashion.

Horses Solve Visible but Not Invisible Displacement Tasks in an Object Permanence Paradigm.

A key question in the field of animal cognition is how animals comprehend their physical world. Object permanence is one of the fundamental features of physical cognition. It is the ability to reason about hidden objects and to mentally reconstruct their invisible displacements. This cognitive skill has been studied in a wide range of species but never directly in the horse (Equus caballus). In this study, we therefore assessed the understanding of visible and invisible displacements in adult Welsh mares in two complementary experiments, using different horses. In experiment 1, visible displacement was investigated using two tasks adapted from the Uzgiris and Hunt scale 1. Invisible displacement was assessed using a transposition task, in which food was first hidden in one of two containers and the location of the containers was then switched. In experiment 2, we further investigated horses’ understanding of visible and invisible displacements using an easier procedure designed to avoid potentially confounding factors. In both experiments, horses successfully completed the tasks involving visible displacement with two or three possible hiding places. However, in both experiments, horses failed the transposition tasks, suggesting that they may not be able to track the displacement of an object that is not directly perceived (i.e., invisible displacement). These results bring new insights into object permanence in horses and how they represent their physical world.

Design of annulus-based dielectric metamaterial cloak with properties of illusion optics

We propose a feasible design for an annulus-based dielectric metamaterial cloak to not only reduce Ohmic losses from metallic metamaterials but also avoid manual misalignment when utilizing discrete dielectric metamaterials. The designed cloak is authenticated by the finite-integration method, and the corresponding field distributions without and with hidden objects are found to reveal the invisibility of the cloak. In addition, illusion optics are comprehended by comparing the field distributions of the dielectric-metamaterial-cloak-based illusion-device and an illusion object. With the abovementioned characteristics of the proposed cloak using an annulus-based dielectric metamaterial, in simulation, we successfully approach the features of the reciprocal cloak, which conceals multiple objects with vision and movement.

Modeling and Identification of Hidden Objects in Dynamic Systems using Digital Filters.

Digital filters are used for identification, prediction, and modeling of hidden objects in dynamic systems. These filters are Gaussian filter with power spectrum depth estimation, edge detection of the hidden objects as well as constructed 2-D geomagnetic modeling of hidden objects. In this paper, digital filter results are obtained by MATLAB software. Magnetometer instrument is used to collect aeromagnetic data of dynamic systems. Aeromagnetic data are collected from Aswan area in Egypt. MATLAB codes are built to insert data and process this data in user graphic interface (UGI). The estimated depth level of hidden objects in dynamic system is selected via the power spectrum which used to transform processed data in time domain to frequency domain. Then, figure out the hidden objects in shallow and deeper levels. Edge boundary is implemented to obtain hidden objects dynamic system either shallow and deep levels. Edges and clearness hidden objects dynamic systems take out by smoothing total horizontal derivative (THDR) and enhanced total horizontal derivative (ETHDR) filter. The estimation depth of hidden objects and their extension are calculated from the 2-D modeling filter. Also, the 2-D model shown the difference hidden objects dynamic systems types through there magnetic susceptibility.