Designers of automatic target recognition algorithms (ATRs) need to compare the performance of different ATRs on a wide variety of imagery. The task would be greatly facilitated by an image complexity metric that correlates with the performance of a large number of ATRs. The ideal metric is independent of any specific ATR and does not require advance knowledge of true targets in the image. No currently used metric meets both these criteria. Complete independence of ATRs and prior target information is neither possible nor desirable since the metric must correlate with ATR performance. An image complexity metric that derives from the common characteristics of a large set of ATRs and the attributes of typical targets may be sufficiently general for ATR comparison. Many real-time, tactical ATRs operate on forward looking infrared (FLIR) imagery and identify, as potential targets, image regions of a specific size that are highly discernible by virtue of their contrast and edge strength. For such ATRs, an image complexity metric could be based on measurements of the mutual discernibility of image regions on various scales. This paper: (1) reviews ATR algorithms in the public domain literature and investigates the common characteristics of both the algorithms and the imagery on which they operate; (2) shows that complexity measurement requires a complete segmentation of the image based on these commonalities; (3) presents a new method of scale-specific image segmentation that uses the mask-driven close-open transform, a novel implementation of a morphological operator; (4) reviews edge detection for discernibility measurement; (5) surveys image complexity metrics in the current literature and discusses their limitations; (6) proposes a new local feature discernibility metric based on relative contrast and edge strength; (7) derives a new global image complexity metric based on the probability distribution of local metrics; (8) compares the metric to the output of a specific ATR; and (9) makes suggestions for further work.

No description available.

Tracking multiple targets in a high cluttered environment where multiple receivers are used is a challenging task due to the high level of false alarms and uncertainty in the track hypothesis. The multi-static active sonar scenario is an example for such systems where multiple source-receiver combinations are deployed. Due to the nature of the underwater environment and sound propagation characteristics, tracking targets in the underwater environment becomes a complex operation. Conventional tracking approaches (such as the Kalman and particle filter) require a predetermined kinematic model of the target. Moreover, tracking an unknown and changing number of targets within a certain search area requires complex mathematical association filters to identify the number of targets and associate measurements to different target tracks. As the number of false detections increases, the computational complexity of conventional tracking system grows introducing further challenges for real-time target tracking situations. The methodology presented in this thesis provides a rapid and reliable tracking system capable of tracking multiple targets without depending on a kinematic model of the target movement. In this algorithm, Self Organizing Maps, Dynamic Programming and the Hough transform are combined to produce tracks of possible targets’ paths and estimate of targets’ locations. Evaluation of the performance of the tracking algorithm is performed using three types of simulations and a set of real data obtained from a sea trial. This research documents the results of experimental testing and analysis of the tracking system. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-08-07 13:21:06.869

No description available.

Introduction Access to radiometals suitable for labeling novel molecular imaging agents requires that they be routinely available and inexpensive to obtain. Proximity to a cyclotron center outfitted with solid target hardware, or to an isotope generator for a radiometal of interest is necessary, both of which can be significant hurdles in availability of less common isotopes. Herein, we describe the production of 44Sc, 68Ga, 89Zr, 86Y and 94mTc in a solution target which allows for the production of various radiometallic isotopes, enabling rapid isotope-biomolecule pairing optimization for tracer development. Work on solution targets has also been performed by other groups [e.g. 1, 2]. Material and Methods Solutions containing a high concentration of natural-abundance zinc nitrate, yttrium nitrate, calcium nitrate [3], strontium nitrate or ammonium heptamolybdate [4] were irradiated on a 13 MeV cyclotron using a standard liquid target. Some of the solutions contained additional hydrogen peroxide or nitric acid to improve solubility and reduce pressure rise in the target during irradiation. Yields calculated using theoretical cross sections (EMPIRE [5]) were compared to the measured yields. In addition, we tested a thermo-syphon target design for the production of 44Sc. Chemical separation of the product from the target material was carried out on a remote apparatus modeled after that of Siikanen [6]. Results and Conclusion The proposed approach enabled the production of quantities sufficient for chemical or biological studies for all metals discussed. In the case of 68Ga, activity up to 480 ± 22 MBq was obtained from a one hour run with a beam current of 7 µA, potentially enabling larger scale clinical production. Considering all reactions, the ratio of theoretical saturation yields to experimental yields ranges from 0.8 for 94mTc to 4.4 for 44Sc. The thermo-syphon target exhibited an increase of current on the target by a factor of 2.5 and an increase in yield by a factor of five for the production of 44Sc. Separation methods were developed for all isotopes and separation efficiency ranges from 71 ± 1 % for 94mTc to 99 ± 4 % for 86Y. 44Sc, 68Ga, and 86Y were successfully used in labeling studies with a model 1,4,7,10-tetrazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelate, while 89Zr coordination behavior was tested using desferrioxamine-alkyne (DFO-alkyne). In summary, we present a promising new method to produce a suite of radiometals in a liquid target. Future work will continue to expand the list of radiometals and to apply this approach to the development of various peptide, protein and antibody radiotracers.

Introduction Solid targets for PET and SPECT radionuclides are getting popular. For radiohalogens the limiting factor, beside the high cost of enriched target material is beam current due to poor heat conductivity of the target material(s). We have designed a honeycomb solid target which has advantages over the traditional circular hole de-sign: 1) Even distribution of target material, 2) it takes higher beam current, 3) less target material loss during distillation (1) and 4) no “creeping” (surface tension phenomena) of the target material during distillation. Material and Methods The target (see FIG. 1.) consists of 19 hexagonal 0.3 mm deep openings (see FIG. 2.) thus having 84% transparency/transmission, in a 24×2 mm platinum disk. There is a 10mm circular cavity on the reverse side giving a 200µm thickness of the platinum. The irradiations were performed on an IBA twin 18/18 Cyclon equipped with a Costis sold target system. The target material thickness was ~300mg/cm2 124TeO2 (> 99.9% I.E., Isoflex) with 5% w/w Al2O3 (99.99%, Sigma-Aldrich). The target was irradiated with 14.8MeV protons (18 MeV degraded by 500µm aluminium). Results and Conclusion The target was able to take beam current up to ~35 µA (higher BCs have not yet been investigated); our “traditional” target (10mm circular hole) has a limit of ~ 20 µA. This means that the effective yield is ~ 50 % higher with the honeycomb as compared with the “traditional” target design.

Introduction Short-lived isomer 83mKr (T½ = 1.83 h) is an ideal calibration source in several low-energy experiments like or KATRIN (determining the neutrino rest mass, monitoring high voltage stability and investigation of the main spectrometer properties) or XENON (detection of the dark matter). The isomer 83mKr is formed by decay of 83Rb (T½ = 86.2 d) that can be produced predominantly via the reaction 84Kr(p,2n)83Rb by irradiation of natKr (57 % abundance of 84Kr). The design and construction of the new gas target for effective production of radionuclide 83Rb as well as target processing will be shortly described. Material and Methods For the target design, we selected the following criteria: minimizing activation of target components; efficient cooling system allowing higher beam currents; easy handling; high life-time of the target chamber (low impact of the irradiation and radionuclide separation process on the target chamber surface and 83Rb recovery). The target consists of three parts: 1. Water cooled aluminium (alloy EN 6082) mechanical interface for easy connection of the target to the beam line. It also serves as a beam collimator (diameter 9 mm). 2. Holder of He-cooled foils (vacuum separation foil – Havar 0.025 mm, target body window – Ti 0.1 mm). 3. Aluminium (alloy EN 6082) water cooled target body with 150mm long cone-shaped target chamber of the volume 27.1 ml. Internal surface of the chamber is nickel-coated. The target filled with natural Kr of purity 0.9999 and absolute pressure 13 bar was irradiated on the external beam of the isochronous cyclotron U-120M of the NPI AS CR. The proton beam energy was set so that it is decreased after deg-radation in the separation foils to 25.6 MeV. Beam energy loss in the natural Kr gas filling is 9.6 MeV. The target was tested up to 25 µA beam current. After irradiation, the target is left for a week to let the short-lived activation products to decay. Then, 83Rb is washed out from the target walls by two portions of freshly prepared de-ionized water, target is rinsed by high-purity ethanol and dried. The two portions of 83Rb aqueous solution are then connected and activity and radionuclidic purity of the product is determined via γ-spectrometry (HPGe detector). Large-distance sample-detector measurements of the target prior and after the separation are used in order to determine recovery of 83Rb. Results and Conclusion The new gas target for routine production of 83Rb was successfully designed, tested and im-plemented for regular 83Rb production. Six-hour irradiation with 15 µA proton beam resulted repeatedly in ca 300 MBq of 83Rb (EOB). Besides 83Rb, we identified in the separated product also 84Rb (T½ = 32.82 d) at levels ca 31 % of the 83Rb activity (EOB) and 86Rb (T½ = 18.631 d) at levels ca 8 % of the 83Rb activity (EOB). Both radionuclidic impurities do not disturb the use of 83Rb, since none of them emanates any radioactive krypton isotope. Moreover, their relative content decreases in time. Rubidium isotopes are recovered from the target almost quantitatively (98–99 %).

Introduction The use of a prefabricated target window assembly greatly simplifies the window installation. The window module is sealed by metal knife-edges, thus eliminating any elestomers in the target construction. Spherical Havar window offers high strength at reduced thickness and does not require helium cooling. The target body is of platinum-plated silver. The target assembly includes an integral beam collimator and a four-sector mask.

Introduction Low melting point metals are often encapsulated in a hermetic container, irradiated and the container transferred to hot-cell for material removal and processing. An important process of this kind is the production of 82Sr from rubidium (melting point: 39.5 °C.) This new concept departures completely form the encapsulated targets approach and allows an almost continues production by the irradiation of the bulk metal. As well, eliminated is the target transfer. By placing the target material dissolution chamber right in the target station, only the dissolution product is pumped to the hotcell for further processing. Material and Methods Some of the disadvantages of the encapsulated target are: 1. Complicated transfer system that is ex-pensive to install, slow and prone to failures. 2. Complex and expensive encapsulation procedure. 3. Loss of production time during the lengthy target changing. 4. Capsule geometry is constrained by the encapsulating process and transfer demands compromising heat transfer and beam power. To avoid the difficulties of liquid metal handling, metal salts are often used instead (rubidium chloride is one example). This creates other problems and limits the beam currents and production yields. In the system described, the liquid metal is transferred (by gravity) from a bulk container to an irradiation chamber. The chamber, made out of nickel-plated silver, holds the correct quantity of rubidium for one irradiation run. Because of the geometry of the chamber and the efficient cooling, up to 40KW of beam power can be delivered to the target. The chamber is equipped with thermocouples and a liquid-metal level detector and is entirely of welded/brazed construction. The alloy foil that forms the beam window is electron-beam welded to the chamber front ring. At the end of irradiation the irradiated liquid metal is gravity fed into a reaction chamber situ-ated below the irradiation chamber, and a new load of fresh rubidium released into the irradia-tion chamber. The liquid-metal transfer and the irradiation components are shown on FIG. 1, and the sectional view on FIG. 2. Appropriate chemicals (n-butanol in the case of rubidium) are delivered to the reaction chamber and the irradiated metal dissolved. The liquid dissolution product is transferred back to the hotcell. Since all steps of the reaction involve liquids, only small diameter tubes connect the target station with the hotcell. The transfer is fast and simple. The bulk liquid-metal storage container can be constructed to hold enough material for 10 or more runs. When empty, it is replaced with a pre-loaded one. The container is connected to the target system with one coupling and the exchange takes a short time. A robotic bottle exchange can be implemented if desired. The station is equipped with its own vacuum system, beam diagnostic (consisting of a four-sector mask) and a collimation. The target chamber and each of the beam intercepting components are electrically insulated to allow beam current monitoring. Constructed entirely out of metal and ceramic the target core assembly does not suffer from radiation damage. The use of aluminum, silver and alumina reduce component activation. Results and Conclusion A large part of the station design is based on the well proven construction of high current solid target system and is using the same, or similar components. Test was performed to optimize the liquid-metal transfer and the chamber filling with the correct volume, while leaving some room for expansion. A process for niobium coating of sliver is investi-gated. Niobium is known to provide good corro-sion resistance against liquid metals. Thermal modelling of the target and flow analysis of the cooling geometry is under way.

The control of introduced mammalian predators in New Zealand forests is crucial for the protection of native species and essential ecosystem services. Possum control in the form of aerial 1080 applications is conducted by TbFree New Zealand to prevent the spread of bovine tuberculosis, and often has the added conservation benefit of temporarily reducing levels of other mammalian predators such as rodents and mustelids. However, native non-target species such as birds and weta can also be at risk of direct and secondary poisoning following 1080 applications, as well as increased predation risk through mesopredator release. To determine whether the benefits of 1080 applications outweigh the risks to non-target native species, both short and long-term monitoring of populations following aerial 1080 applications is needed. For this study, two forest regions in the South Island were selected for pre- and post-treatment monitoring of non-target species following an aerial 1080 application for possum control. Each region contained a treatment site and a paired non-treatment site. Relative indicies of possums, rodents and other mammalian predators were obtained using tracking tunnels and chew cards, indicies of birds were obtained using five-minute bird counts, and indicies of tree weta were obtained using tracking tunnels and artificial shelters. Monitoring was conducted before the aerial 1080 was applied in August 2012, and over the following 2012/13 and 2013/14 summer seasons. The aerial 1080 applications were successful at reducing possums to undetectable levels at both treatment sites for the two seasons following treatment. Mice were significantly reduced at one treatment site relative to the paired non-treatment site immediately following the 1080 operation, but had increased to pre-1080 levels by the second post-treatment monitoring season. Rats were detected at low levels, and showed no response to the treatment. Mustelids were not detected at either region throughout the monitoring period. No native species showed a decline in a treatment site that was not matched in the non-treatment site. Chaffinches significantly declined at both treatment sites relative to non-treatment sites, likely due to an indirect delayed effect such as competition for food resources. Tomtits showed a positive response to the treatment, significantly increasing in both treatment sites over the post-treatment monitoring periods. Tree weta showed no significant decline in response to the treatment. The reduction of possums to low levels, and the maintenance of possum control with ongoing 1080 operations, is likely to continue to provide an overall net benefit to native non-target species.