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Active millimeter wave (AMMW) imaging technique plays an important role in the security check, due to its ability to detect the concealed objects harmlessly without violating privacy. With the rapid development of deep learning, several algorithms have achieved great success in concealed object detection for AMMW images. However, their performance is restricted for the lack of sufficient data, which is the prerequisite for training the deep learning neural network. To address this task, an improved ray tracing (RT) method is proposed to fast solve scattering fields. Specifically, the Blinn-Phong model, which is a simple but effective model in computer graphics rendering, is utilized to simulate the scattering in the target surface. Comparing with the conventional full-wave simulation methods, the proposed method can achieve similar results with much less time. Then the range migration algorithm (RMA) is employed to reconstruct the images. Both visual and numerical results, as well as comparisons with other classical simulation methods, demonstrate the effectiveness and superiority of the proposed improved ray tracing framework in generating AMMW images for deep learning based concealed object detection.

In our noncontact acoustic inspection, a target surface is acoustically excited by strong aerial sound waves, and its vibration velocity distribution is measured by a scanning laser Doppler vibrometer. This time, by a remote measurement over 25m, the internal defects of shotcrete was detected and visualized. With SSE analysis using spatial spectral entropy, the resonance frequencies of the internal defects can be detected. By narrowing the imaging frequency band, clear imaging of the defects was achieved.

The LRP reflects the shape of the target surface and the material properties by acquiring the radial dimension of the target. However, it has been found that by changing the emission pulses, the LRPs by the same target may be different. In addition, different targets may acquire the same LRPs. It makes difficult to identify the target by using LRP. This paper proposes a method base on convolution of time domain, which can solve this problem well.

Noncontact acoustic inspection method using acoustic irradiation induced vibration and laser Doppler vibrometer is an excellent method capable of detecting defects at the same level as hammering test from a long distance, but as the irradiation angle of sound waves increases, detection ability is lowered. This is because it is not possible to apply a uniform surface excitation, so that flexural vibration hardly occurs. However, when the sound source itself is mounted on an unmanned aerial vehicle (UA V)which is becoming widespread in recent years, it is possible to make the sound source position directly face the measurement target surface, and it is expected that the problem of angle dependence will be solved. Therefore, in this research, we tried to produce sound source mounted type UA V and examined using outer wall specimen by noncontact acoustic inspection method.

The adhesion robot has better adhesion performance in a vacuum than others, such as magnetic absorption robot and vacuum adsorption robot. It has broad application prospect and far-reaching practical significance in the field of space On-Orbit Servicing Robots. The stability motion of the adhesion robot on a flat surface has been studied in depth, but the problem of the impact force between the adhesion robot and the flat surface when landing on the surface, which is an inevitable problem that the adhesion robot lands on the flat surface and achieve stable, has been researched little. Therefore, this article has researched about the impact process between adhesion robots and flat surfaces. An impact experiment about the bionic foot was performed on a self-built experimental platform. It reveals the state of motion and the changes of the force between the bionic foot and the flat surface at the moment of impact. The conclusions have been verified on the gecko-inspired robot, and are of great significance for the future adhesion robot to achieve a stable landing on a target surface.

We present a novel technique that allows us to detect, map and quantify changes on the Earth's surface in three-dimensions that occur at time scales of a few seconds. This rapid change detection capability is a byproduct of the development of a multichannel airborne lidar system that scans the target surface at three different times in a single aircraft pass. Results, capabilities, limitations and potential applications are discussed.

Removing large orbital debris in a safe, robust, and cost-effective manner is a long-standing challenge, having serious implications for LEO satellite safety and access to space. Many studies have focused on the deorbit of spent rocket bodies (R/Bs) as an achievable and high-priority first step. However, major difficulties arise from the R/Bs' residual tumble and lack of traditional docking/grasping fixtures. Previously investigated docking strategies often require complex and risky approach maneuvers or have a high chance of producing additional debris. To address this challenge, this paper investigates the use of controllable dry adhesives (cDAs), also known as gecko-inspired adhesives, as an alternative approach to R/B docking and deor-biting. CDAs are gathering interest for in-space grasping and manipulation due to their ability to controllably attach to and detach from any smooth, clean surface, including flat and curved surfaces. Such capability significantly expands the number and types of potential docking locations on a target. CDAs are also inexpensive, are space-qualified (performing well in a vacuum, in extreme temperatures, and under radiation), and can attach and detach while applying minimal force to a target surface, all important considerations for space deployment. In this paper, we investigate a notional strategy for initial capture and stabilization of a R/B having multi-axis tumble, exploiting the unique properties of CDA grippers to reduce maneuver complexity, and we propose alternatives for rigidly attaching deorbiting kits to a R/B. Simulations based on experimentally verified models of CDA grippers show that these approaches show promise as robust alternatives to previously explored methods.

This paper presents an analytical method for calculating the finishing allowance during ultra-precision polishing process of optical freeform surfaces. The finishing allowance is calculated by comparing the target surface with the measured surface obtained from a Coordinate Measuring Machine. Analytical results show that the allowance deviation between the calculated results and the Zeiss professional software is 0.005mm. Material removal matrixes of spherical polishing tool polishing freeform surface are established. Based on the allowance distribution, Nonnegative Least Squares algorithm is used to calculate the dwell time vector. Effect of the polishing tool angle and polishing pressure on remove profile is simulated. Dwell time distribution is acquired based on the optimizing polishing pressure and polishing tool angle parameters. Two kinds of allowance are given to verify the dwell time model. For the first kind of allowance distribution, simulation results show that the PV value is dropped from 1.3× 10−3mm to 4.5× 10−18 mm and the RMS dropped from 0.31× 10−3 mm to 6.29× 10−19 mm after polishing. For the second kind of allowance distribution, the PV value is dropped from 0.34 × 10−3 mm to 1.1 × 10−19 mm and the RMS dropped from 0.11 × 10−3 mm to 6.0 × 10−21 mm after polishing.

Compared to microwave and infrared, THz radar has higher resolution, stronger secrecy, stronger penetrating ability and stronger anti-interference ability. The development of THz radar system depends on the research of THz radar target characteristics. However, different from microwave band, we must take into account the influence of target surface roughness on THz scattering characteristics during developing the research of THz radar target characteristics. This paper studies the influence of metallic target surface with different roughness on THz scattering characteristics through theoretical calculations and experiment.

Proximity relative navigation systems for autonomous small spacecraft and Micro Aerial Vehicles are under continuous investigation, aiming to obtain low-cost and low-resources miniaturized sensors. In this paper, after a review on the state of the art of relative navigation systems for cooperative and non-cooperative miniature space and aerial vehicles, two simple, low cost devices for proximity navigation are presented. The first one is conceived for operation between cooperative vehicles, and exploits a dual system comprising a small camera imaging an array of LEDs and a LED-photodiode couple for precise range estimation based on intensity measurements. The second sensor is designed to perform proximity ranging and attitude determination with respect to non-cooperative objects in space, air or ground. It is based on a miniature camera that detects the light spots on the target surface generated by three lasers mounted on the chaser vehicle. Theoretical models have been developed for both sensors, and were used to perform a preliminary assessment of performance through numerical simulations.

This paper proposes a new method for mapping a tissue surface model onto an arbitrary target surface while preserving the geometrical features of the tissue surface. In our method, firstly, the tissue model is roughly deformed by using Self-organizing Deformable Model. Since the deformed model may contain folded patches, the folded patches are removed. Moreover, by Free-Form Deformation (FFD), and the area- and angle-preserving mapping, the model is mapped onto the target surface while preserving geometrical properties of the original model. From several experimental results, we can conclude that the proposed method can map tissue models onto arbitrary target surface without foldovers.

Summary form only given. THz radiation has wide applications in physics, chemistry, information, security and biology. Applications and studies in the nonlinear regime require strong THz radiation sources. Here, we demonstrate intense half cycle THz radiations produced by ultrashort laser solid targets interactions in both forward and backward direction via particle-in-cell simulations. Radiations with intensity higher than 1014W/cm2 near the target surface with the duration approximates that of the incident laser can be obtained by hundreds of TW lasers. Simulations suggest that the radiations are transition radiation1 induced by hot electrons generated in laser plasma interactions crossing the front and back surface of the target. An overall picture of intense THz generation by laser solid interactions will be presented. Our simulations results are highly consistent with observations from related experiments by other authors2, 3.

Secondary Bjerknes forces can rupture the binding of targeted microbubbles. We have shown before that this effect can be used to quantify the adhesion strength between bubble and target surface [1]. At lower pressures however, microbubbles were observed to snap back to their original position within 100 µs after ultrasound application. In this study the mechanism of this restoring force was investigated in more detail using simultaneous top and side view high speed imaging [2]. Moreover, some results on the process of microbubble detachment (peeling versus uniform rupture) are presented.

This document intends to present a study of configurations for the uniform illumination over a square-target-surface (of task-lighting dimensions) using power LEDs. A particular application of this is the illumination of a carrom board. A lighting scheme involving a distributed arrangement of LEDs that provides a near-uniform illumination level for a given height, is proposed. The optimized parameters for the variables in the arrangement are obtained by the use of MATLAB functions for optimization. The existing lighting system for the illumination of the carrom boards at NITK Surathkal is measured and compared with the proposed arrangement.

To supply higher deposition rate and better target utilization, simple and cost-effective adjustments that can be applied to the existing DC magnetron sputtering systems are desired. By attaching adequate iron annulus and compensation magnetizations, electron trajectories near the target surface can be confined and the target erosion patterns can then be properly controlled. Hence, the target can be more effectively utilized and the substrate deposition rate can also be indirectly enhanced. Three typical patterns have been selected and promising results have showed that the erosion patterns on the targets can be precisely controlled to the designated reference profiles with resemblances higher than 98.78%, along with the substrate sputtering rate enhancements in the range of 20.87%-23.06%. From such verifications, clearly the refinement concepts for better the system performance can be confirmed.

A needle-type dispenser, consists of a thin needle and a glass capillary, has been developed for micro-droplet application from high viscosity liquids. A gap, which is a distance between the needle tip and the target surface, is formed in micro-droplet. If the gap is fluctuated, volumes of applied micro droplets are unstable. Therefore, a contact-detection method of the needle-tip droplet and the target surface is proposed. The needle is vibrated by the piezoelectric element through the leaf spring in the proposed method. Contact of the needle-tip droplet and the target surface can be detected from needle-vibration characteristics. In this paper, control of the gap and droplet volume using needle-vibration characteristics is reported.

A mathematical model is proposed for the target characteristics in laser scattering analysis, using the Bidirectional Reflectance Distributional Function (BRDF) effectively describing the reflective property of the target surface material. The five-parameter genetic algorithm simulated annealing is employed to perform parametric inversion for the semi-empirical statistical expression the BRDF modeled by. On obtaining these parameter values required in the BRDF model, LRCS of the target is then determined in a straightforward manner according to the mathematical relationship between the BRDF and the LRCS. The model is validated by yielding simulated results which agree with the measured data and proves to be an effective approach in evaluating target characteristics in laser scattering analysis.

Based on the principle of infrared radiation, the formulas of the real temperature calculation of a target surface under various conditions were derived. Thereby we obtain the real difference in temperature between two points, so that formulate expressions of the relative temperature difference. And introduce some application of infrared imaging technique in the test of the fault of low-voltage apparatus.

This paper presents a new technique for projecting a 3D object mesh model onto a surface of another target object. The mesh model adapts its shape to the target surface, and is called Self-organizing Deformable Model(SDM). The SDM algorithm works by combining a competitive learning and an energy minimization. The framework of the SDM makes it possible to map a mesh model onto various kinds of target surfaces. This characteristic can not be seen in other methods for surface parameterization, and it enables us to apply the SDM to some different fields in computer vision and computer graphics. Also the SDM can reconstruct shapes of target objects similar to general deformable models.

A new multifingered hand system with quick finger motion of 180deg per 0.1s has been developed. With high-speed visual feedback at a rate of 1kHz, high-speed catching of a falling ball are achieved. In this catching task, a target was dropped from about 1m in height, and the speed of the falling ball became more than about 4m/s just before it hit the ground. The hand could precisely catch it using two fingertips, and the percentage of the success was almost 100%. This successful catching depends on not only high-speed precise motion of the hand, but also softness of the target surface. In this paper, the dynamical analysis of the high-speed catching is proposed, and the softness of the target surface makes very important roles in this tasks. As a result it is shown that the balanced impedance of the target surface and the feedback control of the hand is needed in order to achieve stable catching.

Although the analysis of GSR using SEM/EDX has been thoroughly studied, no literature on the SEM/EDX analysis of primer mixtures of center-fired cartridges has been reported. Thus, not only GSR but also primer mixtures generated from both reference cartridges and confiscated illegal cartridges were analyzed in this work. The aim of this work is to obtain elemental composition data of primer mixtures of handgun cartridges frequently encountered in Taiwan and to provide procedures for identifying cartridge used in criminal activities through elemental analysis of GSR and primer mixtures of suspected cartridge. Twenty-five kinds of cartridges with noncorrosive primers or lead-free primers were disassembled or test-fired to collect primer mixtures or GSR, respectively. Bullet and propellants of unfired ammunition were removed, the cartridge case was deprimed, and primer mixtures were then recovered. Gunshot residue samples were collected from shooter's hand, spent cartridge case, and target surface after test firing. Both primer mixture and GSR samples were then subjected to SEM/EDX analysis. The results revealed that all of the noncorrosive primer mixtures and GSR generated from cartridges with these primers contained unique elemental composition of lead (Pb), barium (Ba), and antimony (Sb). Only Ba and Sb were detected in two kinds of lead-free primer mixtures and GSR generated from cartridges with these primers, where none of Pb, Ba, and Sb were detected in samples from the other four kinds of lead-free cartridges. Characteristic elements of Pb, Ba, and Sb were detected in all primer and GSR samples collected from illegal cartridges and were not detected in samples from police duty cartridges. These results indicated that lead-free cartridges have not yet been used by criminals in Taiwan. The significant elemental difference between GSRs from different sources is especially useful in identifying possible shooter while the fired bullet is missing.

For automated spray painting robots, the choice of a start curve from which all subsequent paths will be determined, plays a critical role in ensuring uniform coverage of the target surface. In this paper, we ultimately propose a method to determine the start curve for two different procedures of coverage path construction. For the first procedure, we average the target surface normal to optimize the average error between desired and resultant deposition with the added goal of minimizing cycle time. For the second technique, we make recourse to the Gauss-Bonnet theorem to minimize the non-uniformity of paint deposition and cycle time for the entire coverage path.

Development and testing of a two dimensional magnetic field sensor are conducted to gain an understanding of the sensing phenomenon, characterize its capabilities, and develop a rationale for the direction of further improvements. The sensor uses a configuration similar to a vidicon television camera tube. Instead of operating in a light sensitive mode, a special target surface is used in conjunction with a modified tube structure and operating conditions. The appearance of magnetic fields observed on the monitor of the prototype seemed foreign until further analysis was performed of the phenomenon causing the images. Experimental results from a prototype are used to develop an understanding of the sensor. From the model developed, computer simulation pointed to an unusual sensing capability that was later verified with the prototype. >

Losses of charge carried by Ag ions emitted from a laser-produced plasma are measured up to a distance of 187 cm from the target. The plasma was generated by a high power iodine laser delivering the power density up to /spl sim/10/sup 15/ W/cm/sup 2/ on the target surface. Two ion collectors of different construction located coaxially were applied, which made the ion current measurement in the same direction and at two distances from the target simultaneously possible. The variation of the charge, /spl Delta/Q, of ions escaping the plasma at /spl sim/10/spl deg/ to the target normal with the distance, L, from the target was found to be of the form /spl Delta/Q/spl sim/L/sup -2/.

We address the task of covering a closed orientable surface embedded in /spl Rfr//sup 3/ without any prior information about the surface. For applications such as paint deposition, the effector (the paint atomizer) does not explicitly cover the target surface, but instead covers an offset surface-a surface that is a fixed distance away from the target surface. Just as Canny and others use critical points to look for changes in connectivity of the free space to ensure completeness of their roadmap algorithms, we use critical points to identify changes in the connectivity of the offset surface to ensure full surface coverage. The main contribution of this work is a method to construct unknown offset surfaces using a procedure, also developed in this paper, to detect critical points.