Determining the shape of one or several objects in an image is a fundamental task for many imaging systems. We propose here a general review of new techniques based on the information theory principles, which allows one to determine segmentation techniques without parameter to be tuned by the user. These techniques are quite general since they include, polygonal and spline parametric shape descriptions, level set models of contour and homogeneous partition of images. This approach can take into account the physical nature of the grey level fluctuations and is thus adapted to different new imaging systems. Furthermore, it can lead to fast algorithms (from a few hundred of ms to a few seconds depending on the complexity of the task to perform on 256 x 256 pixel images).

Automatic target detection and recognition (ATD/R) remains a challenging problem for unmanned and unattended systems. Promising solutions using Electro-Optical sensors such as LADARs, FLIRs, and TVs are evolving. The key issues are not only the performance of the individual sensors, but also the mutual calibration of the sensors and their collective behavior. This paper presents an overview of the challenges encountered in two separate ATD/R scenarios, and the methods that have been proposed for addressing them. Specifically, advanced techniques that exploit multiple views, collaborative sensor behavior and new sensing paradigms are reviewed and the concepts are illustrated by means of several examples.

We present the results of applying data compression techniques to encrypted three-dimensional (3D) objects. The objects are captured using phase-shift digital holography and encrypted using a random phase mask in the Fresnel domain. Both the amplitude and the phase of our 3D objects are encrypted using this technique. The advantage of a digital representation of the optical wavefronts is that they can be processed and transmitted using conventional means. Arbitrary views of the 3D objects are decrypted and reconstructed using digital propagation. Compression is applied to the encrypted digital holograms prior to transmission. Degradation due to lossy quantization compression is measured in the reconstruction domain. Finally, we use a speedup metric to validate that our compression techniques are viable for time-critical 3D imaging applications. Our techniques are suitable for a range of secure 3D object storage and transmission applications.

Active and passive optical identification (ID) tags and readers for remote identification and verification of objects are described. We focus our attention on the design of passive ID tags to achieve distortion-invariant authentication of the information included in the optical tag. A passive ID tag will consist of an optical phase code which can be placed in a visible part of an object for remote detection. We aim to authenticate the object even if the reader captures a distorted version of the code due to in-plane rotations. Distortion-invariance is achieved by both multiplexing the information included in the ID tag and the topology of the tag. For security purposes, double-phase encryption has already been shown as an appropriate technique to encode information. By using double-phase encryption, a signature is hidden in a phase-encoded ID tag not visible by visual inspection. Once the ID tag is captured by the reader and is decrypted, a correlation-based processor verifies the decoded information with a previously stored reference signal. The proposed system may have broad applications in transportation, homeland security, and inventory control.

Vanishing point and Z-tranform image center calibration techniques are reported for a prototype “compound-eye” camera system which can contain up to 25 “eyelets”. One application of this system is to track a fast-moving object, such as a tennis ball, over a wide field of view. Each eyelet comprises a coherent fiber bundle with a small imaging lens at one end. The other ends of the fiber bundles are aligned on a plane, which is re-imaged onto a commercial CMOS camera. The design and implementation of the Dragonfleye prototype is briefly described. Calibration of the image centers of the eyelet lenses is performed using a vanishing point technique, achieving an error of approximately ±0.2 pixels. An alternative technique, the Z-transform, is shown to be able to achieve similar results. By restricting the application to a two-dimensional surface, it is shown that similar accuracies can be achieved using a simple homography transformation without the need for calibrating individual eyelets. Preliminary results for object tracking between eyelets are presented, showing an error between actual and measured positions of around 3.5 mrad.

Sensing systems in living bodies offer a large variety of possible different configurations and philosophies able to be emulated in artificial sensing systems. Motion detection is one of the areas where different animals adopt different solutions and, in most of the cases, these solutions reflect a very sophisticated form. One of them, the mammalian visual system, presents several advantages with respect to the artificial ones. The main objective of this paper is to present a system, based on this biological structure, able to detect motion, its sense and its characteristics. The configuration adopted responds to the internal structure of the mammalian retina, where just five types of cells arranged in five layers are able to differentiate a large number of characteristics of the image impinging onto it. Its main advantage is that the detection of these properties is based purely on its hardware. A simple unit, based in a previous optical logic cell employed in optical computing, is the basis for emulating the different behaviors of the biological neurons. No software is present and, in this way, no possible interference from outside affects to the final behavior. This type of structure is able to work, once the internal configuration is implemented, without any further attention. Different possibilities are present in the architecture to be presented: detection of motion, of its direction and intensity. Moreover, some other characteristics, as symmetry may be obtained.

The nonlinear optical properties of many materials and devices have been the main object of research as potential candidates for sensing in different places. Just one of these properties has been, in most of the cases, the basis for the sensing operation. As a consequence, just one parameter can be detected. In this paper, although just one property will be employed too, we will show the possibility to sense different parameters with just one type of sensor. The way adopted in this work is the use of the optical bistability obtained from different photonic structures. Because this optical bistability has a strong dependence on many different parameters the possibility to sense different inputs appears. In our case, we will report the use of some non-linear optical devices, mainly Semiconductor Optical Amplifiers, as sensing elements. Because their outputs depend on many parameters, as the incident light wavelength, polarization, intensity and direction, applied voltage and feedback characteristics, they can be employed to detect, at the same time, different type of signals. This is because the way these different signals affect to the sensor response is very different too and appears under a different set of characteristics.

This paper presents investigation results of a new generation of the fibre optic perimeter sensor in a two Sagnac interferometers configuration. This system can detect a potential intruder and determine its position along a protected zone. A multiresolution wavelet analyses of the signal is used to determine its start point. First, we made use of decomposition, thresholding and reconstruction of the signal by means of a Daubechies wavelet. Consequently, high-frequency noise was removed from the signal. Next, the signal was exposed to an approximation process by means of a multiresolution Haar wavelet. Statistical analysis of this signal enabled us to determine an amplitude criterion for calculation of a start point for slowly-changeable signals. The criterion was a standard deviation of the amplitude increase of the signal after approximation. Arrangement of a laboratory model of the sensor and its signal processing scheme is presented. During research of a laboratory model, it was possible to detect the position of the disturbance with resolution of about 20 m along a 6-km long section.

QinetiQ have been developing security systems for land and sea applications using interferometric based fiber optic sensors. We have constructed and tested a multi-channel fiber-optic hydrophone seabed array, which is designed for maritime surveillance and harbor security applications. During a recent trial it was deployed in a coastal location for an 8 day period during which it successfully detected and tracked a wide variety of traffic. The array can be interfaced with an open architecture processing system that carries out automatic detection and tracking of targets. For land based applications we have developed a system that uses high sensitivity fiber optic accelerometers and buried fiber optic cable as sensor elements. This uses the same opto-electronic interrogator as the seabed array, so a combined land and sea security system for coastal assets could be monitored using a single interrogator.

In this paper, a new scheme for detection of the moving target’s height and trajectory using the pan/tilt-embedded stereo camera system is suggested. That is, the moving target is extracted from the left image by using a threshold value of YCbCr color model and then, the location coordinates of the target can be obtained by carrying out the phase-type correlation between the segmented target image and the right image. At then, these values are used to control the pan/tilt system through the modified PID-based recursive controller. Moreover, with the geometric parameters between the target and stereo camera system, the distance from the center of the stereo camera system to the target and the direct distance from the camera to the target can be computed so that, the 3-dimensional location coordinates of the target can be finally obtained in the real world and as a result, the height value of the target can be extracted using the difference between z coordinate value of the target and the height of the pan/tilted-embedded stereo camera system on the desk. From some experiments using 780 frames of the input stereo image pairs, it is analyzed that error ratio of the position displacement of the target in the horizontal and vertical directions after tracking is kept to be very low value of 1.5%, 0.42%, respectively and error ratio between the measured and computed height value of the target is also kept to be very low value of 0.5% on average.

This paper presents an application implying higher order statistics in source localization. Such techniques have been first introduced in the early 1990’s. Some interesting properties of higher order statistics are exploited in zone survey applications. A large global array constituted by a set of moving sub-arrays (soldiers wearing a Head Equipment (HE) equipped with one or more microphones, a GPS receiver and a magnetometer) allows the localization of the menaces near a survey zone. Studying a large global array, with second order statistics high resolution localization techniques, the local informations are not significant enough in order to have an influence on the estimation of the position of the acoustic sources (for instance, the orientation of the HE has no influence on the estimation of the position of the sources). We expect that the use of higher order statistics and their properties concerning especially the virtual equivalent network (VEN) will improve the significance of these local information and thus, allow to have a better estimation of the source position. A first study has been based on simulations, and then, some results with real data, collected in october 2003, are presented.

General Sensing Systems (GSS) has developed a sensor based on electrets material. Herein we describe the creation and lab testing of this very small and high performance seismic sensor intended for up-to-date security and military systems. This article delivers the first results of laboratory tests of this small size and extremely low cost new sensor. This new sensor was compared with the most popular geophones, the GS-14-L3 and GS-20DX geophones produced by Geo Space Corporation. The results show that the new, GSS sensor has an expanding frequency response range in both the low and high frequency areas. This is crucial for increased detection range of seismic-acoustic and hydro acoustic reconnaissance systems. The new, GSS sensor also has the highest sensitivity among all the compared geophones as well as a lower sensitivity threshold. When the amplitude of vibrations is very small, the GS-14-L3 and GS-20DX geophones, for example, miss signals-whereas the new sensor has a good response. Specifically, this performance characteristic of the new GSS sensor also allows the development of reconnaissance systems with a high detection range. Test results also show that the new sensor demonstrates good signal discrimination, ensuring efficient signal interpretation. In general, the results reported here show that the use of electrets materials enables the manufacture of very small and inexpensive seismic-acoustic and hydro acoustic sensors with improved performance characteristics.

Acoustic sensors have had a long history of use in military applications. Some of the factors favoring their use are: their ability to exploit loud and distinctive emissions of vehicles and weapons firings, their capability to detect and track targets in non line-of-sight conditions, and the ability to carry out their mission in a totally passive way (no emissions to give out their position). Acoustic-seismic sensors can also be implemented using low-power electronics. Acoustic-seismic sensors are now found in various surveillance sensors, generally known as Unattended Ground Sensors or UGS. The trend towards increasing computational capabilities, lower power consumption and better communications capacity have made these devices more useful and acceptable in a variety of military and peace-keeping operations. The promise of networked sensors has opened the possibility of large-scale sensor networks. However, we must be realistic about what can and cannot be achieved within the current technical horizon. The dream of “sensor dust”: miniature devices, built and deployed at minimum cost, transmitting volumes of data is at present, just that, a dream that has to be tempered with the realities imposed by physics.

Digital modulation schemes have been thoroughly examined over the last decades in order to improve the performance over wireless channels in terms of capacity or BER vs SNR. Sensor networks belong to a special category of wireless networks where energy awareness may be more important than any other aspect such us bandwidth efficiency or Quality of Service. Hence, the criteria in order to choose the appropriate modulation scheme are quite different from any other application. In this paper we examine the available modulation schemes taking into account energy constraints, and based on an existing model, we propose an adaptive modulation scheme as a means to achieve better performance in terms of energy consumption.

The MicroSensors Systems (MSS) Program is developing a layered sensor network to detect dismounted threats approaching high value assets. The MSS subsystem elements include sensitive receivers (capable of detecting<<1 Watt emissions in dense signal or degraded signal environments) and low power, miniature, disposable sensors (acoustic, magnetic, and infrared). A novel network protocol has been developed to reduce the network traffic resulting in conservation of system power and lower probability of detection and interception. The MSS program will provide unprecedented levels of real-time battlefield information, greatly enhancing combat situational awareness when integrated with the existing Command, Control, and Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) infrastructure. This system will provide an important boost to realizing the information dominant, network-centric objective of Joint Vision 2020. The program has established two Centers of Excellence for Sensor Technology each of which is capable of designing and building next generation, networked microsensor systems. The Defense Microelectronics Activity has teamed with the Centers of Excellence and industry to preserve long-term Department of Defense access to key next generation manufacturing technologies.

The nature of many current Intelligence, Surveillance, Target Acquisition and Reconnaissance (ISTAR) sensor systems requires that they are controlled at an operational or strategic level. The trend towards asymmetric/urban warfare has created the necessity for tactical commanders to be empowered with a similar ISTAR capability but over a reduced area. The variable temporal, spatial and cost constraints imposed by each scenario requires an adaptable organic sensory system to be developed to support the tactical commander. Unmanned Disposable Organic Sensor Networks (DOSNs) are promising to provide sensory solutions in many tactical situations. However in order to develop a suitable DOSN it is necessary to identify the optimum realisation to meet the tactical commanders requirements. In this paper the work conducted by QinetiQ for elements of the UK MOD is discussed. This includes: 1) A method for assessing the value of each specific realisation of a DOSN against a range of scenarios. 2) Description of models used to generate an understanding of the capability of DOSN systems. 3) Description of an experimental DOSN system with associated trial results and plans to validate the models discussed above. The technical approach employed could also be used to assess the applicability of DOSN systems across a range of other military ISTAR requirements.

In Urban Warfare, the enemy is at close range; snipers are almost always present; stress is extremely high; and the opposing force is frequently indistinguishable from the civilian population. On-going events in the Middle East and the general rise in world-wide terrorism has shown that small cells of “terrorist” forces are able to inflict severe developments in Urban Warfare sensors and their possible role.

Chemical/Biological/Radiological/Nuclear/Explosives (CBRNE) is a threat to all forces that deploy to any part of the globe. Lightweight expeditionary forces are especially vulnerable because they operate with minimum force structure in or near enemy forces and may become indirect targets due to the proximity of opposing forces. There is currently no integrated tactical, agile CBRNE detect-to-warn and detect-to-treat detection system suitable for lightweight expeditionary forces. The current solutions are often outside the deployment and support constraints of expeditionary forces. Expeditionary forces, typically, require a 30-day capability without re-supply and must maximize resources. Situational awareness is limited with little or no automation. Due to the limitations in existing detectors, no detector has been found to be the magic bullet for all types of agents. An array of sensors that are redundant and overlap the capabilities of each and the limitations of each technology, on the other hand, would provide a level of security that is progressively more acceptable to the warfighter. Initially, the array will be composed of integrated commercial-off-the-shelf (COTS) and government-off-the-shelf (GOTS) CBRNE samplers, identification devices, tamper sensors, and communications and alert equipment. The sensor array will plug-and-play new technologies as they become available.

Guarding safety and security within industrial, commercial and military areas is an important issue nowadays. A specific challenge lies in the design of portable surveillance systems that can be rapidly deployed, installed and easily operated. Conventional surveillance systems typically employ stand alone sensors that transmit their data to a central control station for data-processing. One of the disadvantages of these kinds of systems is that they generate a lot of data that may induce processing or storage problems. Moreover, data from the sensors must be constantly observed and assessed by human operators. In this paper, a surveillance concept based on distributed intelligence in wireless sensor networks is proposed. In this concept, surveillance is automatically performed by means of many small sensing devices including cameras. The requirements for such surveillance systems are investigated. Experiments with a demonstration system were conducted to verify some of the claims made throughout this paper.

Since untethered sensor nodes operate on battery, and because they must communicate through a multi-hop network, it is vital to optimally configure the transmit power of the nodes both to conserve power and optimize spatial reuse of a shared channel. Current topology control algorithms try to minimize radio power while ensuring connectivity of the network. We propose that another important metric for a sensor network topology will involve consideration of hidden nodes and asymmetric links. Minimizing the number of hidden nodes and asymmetric links at the expense of increasing the transmit power of a subset of the nodes may in fact increase the longevity of the sensor network. In this paper we explore a distributed evolutionary approach to optimizing this new metric. Inspiration from the Particle Swarm Optimization technique motivates a distributed version of the algorithm. We generate topologies with fewer hidden nodes and asymmetric links than a comparable algorithm and present some results that indicate that our topologies deliver more data and last longer.

Real-time and detailed information is critical to the success of ground combat forces. Current manned reconnaissance, surveillance, and target acquisition (RSTA) capabilities are not sufficient to cover battlefield intelligence gaps, provide Beyond-Line-of-Sight (BLOS) targeting, and the ambush avoidance information necessary for combat forces operating in hostile situations, complex terrain, and conducting military operations in urban terrain. This paper describes a current US Army program developing advanced networked unmanned/unattended sensor systems to survey these gaps and provide the Commander with real-time, pertinent information. Networked Sensors for the Combat Forces plans to develop and demonstrate a new generation of low cost distributed unmanned sensor systems organic to the RSTA Element. Networked unmanned sensors will provide remote monitoring of gaps, will increase a unit’s area of coverage, and will provide the commander organic assets to complete his Battlefield Situational Awareness (BSA) picture for direct and indirect fire weapons, early warning, and threat avoidance. Current efforts include developing sensor packages for unmanned ground vehicles, small unmanned aerial vehicles, and unattended ground sensors using advanced sensor technologies. These sensors will be integrated with robust networked communications and Battle Command tools for mission planning, intelligence “reachback”, and sensor data management. The network architecture design is based on a model that identifies a three-part modular design: 1) standardized sensor message protocols, 2) Sensor Data Management, and 3) Service Oriented Architecture. This simple model provides maximum flexibility for data exchange, information management and distribution. Products include: Sensor suites optimized for unmanned platforms, stationary and mobile versions of the Sensor Data Management Center, Battle Command planning tools, networked communications, and sensor management software. Details of these products and recent test results will be presented.

This paper examines some of the challenges facing the community in providing radio communications to enable information systems for military operations. We believe that much of the on-going/completed work is necessary, but not sufficient, to provide the military Network Centric Operations, which integrates military’s network centric enterprise with network centric warfare. Additional issues need to be addressed to better support battle commanders as well as decider-sensor-effecter linkages. We discuss a possible way ahead.

Modal Interference Fiber Optic Sensor (MIFOS) for permanent monitoring of the network is presented. A mechanical disturbance of a fiber cable influences on intensity distribution at the end-face of a multimode fiber. Variations in interfering images are analysed by means of a digital processing unit that determines the alarm in case of unauthorized access along the whole length of the fiber. A contrast of an interference pattern and a procedure of fiber optic selection for the sensor are shown. A simple criterion that bases on changes of local maximums positions of the interference patterns is applied. A laboratory arrangement of the sensor and its experimental research are shown.

Denial of service attacks, viruses and worms are common tools for malicious adversarial behavior in networks. Experience shows that over the last few years several of these techniques have probably been used by governments to impair the Internet communications of various entities, and we can expect that these and other information warfare tools will be used increasingly as part of hostile behavior either independently, or in conjunction with other forms of attack in conventional or asymmetric warfare, as well as in other forms of malicious behavior. In this paper we concentrate on Distributed Denial of Service Attacks (DDoS) where one or more attackers generate flooding traffic and direct it from multiple sources towards a set of selected nodes or IP addresses in the Internet. We first briefly survey the literature on the subject, and discuss some examples of DDoS incidents. We then present a technique that can be used for DDoS protection based on creating islands of protection around a critical information infrastructure. This technique, that we call the CPN-DoS-DT (Cognitive Packet Networks DoS Defence Technique), creates a self-monitoring sub-network surrounding each critical infrastructure node. CPN-DoS-DT is triggered by a DDoS detection scheme, and generates control traffic from the objects of the DDoS attack to the islands of protection where DDOS packet flows are destroyed before they reach the critical infrastructure. We use mathematical modelling, simulation and experiments on our test-bed to show the positive and negative outcomes that may result from both the attack, and the CPN-DoS-DT protection mechanism, due to imperfect detection and false alarms.

Solar blind ultraviolet communication systems can provide short to medium range non line-of-sight and line-of-sight links which are covert and insensitive to meteorological conditions. Operation in the solar blind region provides zero background conditions and strong scattering interactions. Scattering provides the basis for transferring information when non line-of-sight conditions exist. Zero background conditions are a result of strong absorption of solar radiation in the upper atmosphere. These conditions make it possible to operate very sensitive wide field-of-view quantum noise limited photon counting receivers, and provide communication systems that perform very differently than free space optical systems that operate in other spectral regions. These systems may be compact and require very low primary power for operation. Non line-of-sight ultraviolet communication systems can provide reliable inter-nodal communications for unattended ground sensor networks. This type of system is particularly attractive when non line-of-sight conditions exist between nodes, covert operation is required, and insensitivity to positioning and ground proximity are desired. Light emitting diode technology being developed under the DARPA SUVOS program represents an enabling technology for these systems. Small, low power and low cost systems compatible with unattended ground sensor networks will be available as a result of this program. Data rates of hundreds of kbps with bit error rates (BER) of 10-7 and inter-nodal ranges of hundreds of meters are consistent with phenomenology and technology. Line-of-sight ultraviolet communication systems also offer some unique characteristics for exfiltration of data from an unattended ground sensor network. The absence of background radiation makes it possible to operate with wide field-of-view receivers and large transmitter cone angles. This capability significantly reduces acquisition/pointing/tracking requirements that are traditionally associated with free space optical links. In addition, strong forward aerosol scatter in the ultraviolet reduces dependence on meteorological conditions. The operational range of line-of-sight solar blind communication systems is on the order of kilometers. By selection of operating wavelength within the solar blind region, performance can be optimized to provide reliable communications and at the same time provide covert operation. Data rates on the order of megabits per second are possible with line-of-sight systems.

Intelligent storage systems run on different advanced technologies, such as linear layout, business intelligence and data mining. Security, the basic desire of the storage system, has been focused on with the indraught of multimedia communication technology and sensors’ network. Along with the developing of science and the social demands, multifarious alarming system has been designed and improved to be intelligentized, modularized and have network connections. It is of great moment to make the storage, and further more, the logistics system more and more efficient and perfect with modern science and technology. Diversified information on the spot should be caught by different kinds of sensors. Those signals are treated and communicated to the control center to give the further actions. For fire-proofing, broad-spectrum gas sensors, fume sensors, flame sensors and temperature sensors are used to catch the information in their own ways. Once the fire is taken somewhere, the sensors work by the fume, temperature, and flame as well as gas immediately. Meanwhile the intelligent control system starts. It passes the tidings to the center unit. At the same time, it sets those movable walls on to work quickly to obstruct the fire’s spreading. While for guarding the warehouse against theft, cut-off sensors, body sensors, photoelectric sensors, microwave sensors and closed-circuit television as well as electronic clocks are available to monitor the warehouse reasonably. All of those sensors work in a net way. The intelligent control system is made with a digital circuit instead of traditional switch one. This system can work in a better way in many cases. Its reliability is high and the cost is low.

Quantum Magnetics has developed an autonomous battery-powered magnetic sensor node for distributed wireless sensor networks. The device digitizes the sensor output signals and transmits data over an RF link using a ZigBee 802.15.4 protocol. The prototype node incorporates Magneto-Resistive (MR) chips configured to measure all three components of the magnetic field, a logic device, analog-to-digital converters, a two-axis tilt sensor, a wireless transceiver, and a set of batteries. For use in outdoor environments, the sensor node is also GPS-ready. At present, the unit measures approximately 4 inches on a side, with about 40% of the volume occupied by the batteries. Using battery power, the node can operate for about 10 hours in a continuous mode and up to 40 hours with a 10% duty cycle. Efforts are underway to develop the next-generation magnetic node with significant reduction in size and part count.