Robust landmine detection from thermal image time series using Hough transform and rotationally invariant features

ABSTRACT

Automated detection of buried anti-personnel landmines using remote sensing techniques is very important for clearing minefields without putting lives in danger. Although thermal infrared imaging is promising, it is far from applicable to the real world in its current state-of-the-art. The most serious problem is that experiments are generally held using sandboxes or levelled and cleared soil, but real fields are, at least partially, covered with plants. In this study, we present an algorithm for landmine detection that is robust enough to detect beyond the clutter caused by partial plant cover. The first part is a hypothesis generator based on circular Hough Transform applied to images that are filtered to enhance circular structures. The second part tests the candidate landmine coordinates using rotationally invariant features, including modified Histogram of Oriented Gaussians (HOG), over multiple images taken at different times after Wiener filtering to maximize signal-to-clutter ratio. The performances of various features and classifiers are compared. The overall performance of the algorithm is demonstrated on a dataset of real-world landmine images contaminated by simulated plants. Satisfactory results are obtained up to 40% equivalent plant coverage where more than 65% of the pixels are fully or partially covered by plants.     

Brown�CRobinson method for interval matrix games

In this paper, two-person interval matrix games are considered, and by means of acceptability index, Brown–Robinson method to find a mixed-strategy equilibrium is adapted to interval matrix games. Numerical examples are also given.     

Performance evaluation of network mobility handover over future aeronautical data link

The aviation community is currently working on the standardization of data communication systems for the future air traffic management. In this context, International Civil Aviation Organization (ICAO) has initiated a work on standardization of an IPv6-based aeronautical telecommunications network and on future radio access technologies, respectively. In this paper, we integrate L-Band Digital Aeronautical Communications System Option 1 (L-DACS 1), which is one candidate for future radio access technologies, with realistic IPv6-based network layer functionality and analyze the effect of handover delay to the TCP performance. Realistic Frame Error Rate (FER) values obtained from an L-DACS 1 physical layer simulator, which uses a realistic aeronautical channel model, are used in the simulation experiments. In the first stage, we decreased layer 3 handover latency by removing the Duplicate Address Detection (DAD) procedure for address configuration. In the second stage, we introduced a Home Agent (HA)-buffering method, which is used to buffer the traffic (destined to the mobile node) during handover. Transmission completion time is the primary performance metric in our analysis. With the HA-buffering method, the transmission completion time is reduced by at least 10% for the transmission of 110 kB of information over a wireless link with 31.5 kbit s⁻¹ data rate.     

Shortest hop multipath algorithm for wireless sensor networks

Shortest hop or distance path is one of the most common methods used for relaying messages in a wide variety of networks. It provides an efficient message relaying to destination in terms of energy and time. There are many algorithms for constructing shortest hop or distance path. However, according to our knowledge, no algorithm for constructing a shortest hop multipath for wireless sensor networks (WSNs) has yet been proposed in the literature. In this paper, we propose a novel distributed shortest hop multipath algorithm for WSNs in order to generate energy efficient paths for data dissemination or routing. The proposed algorithm generates shortest hop braided multipath to be used for fault-tolerance or load-balancing. It guarantees the BFS tree and generates near optimal paths in O(V.D+V) message complexity and O(D²) time complexity regarding the communication costs towards the sink after termination of algorithm.     

Mechanical properties of HTPB-IPDI-based elastomers

A polyurethane elastomer having mechanical and adhesive properties suitable for liner applications in solid rocket propellants was developed using HTPB as the prepolymer and IPDI as the curing agent. The effects of the NCO/OH ratio (R value) and the trio/diol ratio on the mechanical properties of the polyurethane matrix were investigated. The reaction of HTPB and IPDI is followed by monitoring the changes in the IR absorption bands of the NCO stretching at 2255 cm⁻¹ and the CO stretching at 1730 cm⁻¹. It was found that the rate of the polyurethane formation obeys an overall second-order kinetics. At an R value of 1.15, the elastomer shows the maximum tensile strength and 200% elongation at break. The hardness, elongation, and the tensile strength reach a steady value around the same R value. The elastomers having a triol/diol ratio less than 0.03 show a decrease in the tensile strength and modulus with a concomitant increase in elongation. At a triol/diol ratio greater than 0.05, the tensile strength increases to about the same value for the liner composition without any triol component. The elongation reaches a steady level at a triol/diol ratio of 0.10 and one observes a steady increase in hardness up to 0.5. The modulus for the compositions having a triol/diol ratio greater than 0.1 is about 50% higher than that for the composition without triol. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2347–2354, 1997     

Determinations of ~(171)Er half-life and some ~(171)Tm transition energies

The neutrons have been captured by Erbium nuclei which were received by using clinical electron linear accelerator. In this experiment, the possibility of the neutron capture process has been observed because of emitted neutrons appearing in the experimental area. In particular,neutron capture of ~(170)Er nucleus has been observed. After the neutron capture of ~(170)Er nucleus, the unstable ~(171)Er has been formed and decayed into the ~(171)Tm. By using this reaction path, some transition energies of ~(171)Tm obtained from the residual activity measurements and the half-life of ~(171)Er have been determined, and they are in agreement with adopted values in the literature.     

A practical hole testing technique using a meter display eddy current instrument

A practical technique for the detection of cracks emanating from holes was investigated for non-ferrous materials using the eddy current method. This technique is suggested when more appropriate test equipment is not available. An unshielded absolute pencil probe and a meter display instrument were utilized in the study. It was determined that holes with a minimum diameter of 6.5 mm can be tested efficiently for the detection of cracks at least 0.15 mm deep. For the equipment used, the hole depth that can be tested is limited about 11 mm if access from the other side is not possible. The detection capability was confirmed by an impedance plane display instrument using rotary differential probes.     

Thermal Behaviors of Bisazocalix[4]arene Derivatives

In this article, calix[4]arene (4) was prepared by debutylation and hydrolyses reacting from 25,27-dibenzoyl-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl)calix[4]arene (2). Azocalix[4]arenes (6a-c) were coupled by linking 4-methoxy, 4-ethyl, and 4-nitroaniline to calix[4]arene (4) through a diazo-coupling reaction. Thermal behavior characteristics and decomposition routes of 25,26,27,28-tetrahydroxy-11,23-di(tert-butyl)-5,17-(p-substitue phenyl)azocalix[4]arene (6a-c) were investigated in air atmosphere by means of thermogravimetry (TG), differential thermogravimetry (DTG), and differential thermal analysis (DTA) analyses. It was found that the decomposition of all compounds complete with two exothermic stages which corresponded to removal of substitute groups (methoxy-, ethyl-, nitro-) and second stage rest of structure decomposition.