<p>On-board imaging is useful for guiding radiation to patients in the treatment position; however, current treatment-room imaging modalities are not sensitive to physiology - features that may differentiate tumor from nearby tissue or identify biological targets, e.g., hypoxia, high tumor burden, or increased proliferation. Single photon emission computed tomography (SPECT) is sensitive to physiology. We propose on-board SPECT for biological target localization.</p><p>Localization performance was studied in computer-simulated and scanner-acquired parallel-hole SPECT images. Numerical observers were forced to localize hot targets in limited search volumes that account for uncertainties common to radiation therapy delivery. Localization performance was studied for spherical targets of various diameters, activity ratios, and anatomical locations. Also investigated were the effects of detector response function compensation (DRC) and observer normalization on target localization. Localization performance was optimized as a function of iteration number and degree of post-reconstruction smoothing. Localization error patterns were analyzed for directional dependencies and were related to the detector trajectory. Localization performance and the effect of the detector trajectory were investigated in a hardware study using a whole-body phantom.</p><p>Typically targets of 6:1 activity were localized as accurately using 4-minute scans as those of 3:1 activity using 20-minute scans. This trend is consistent with the relationship between contrast and noise in the contrast-to-noise ratio (CNR) and implies that higher contrast targets are better candidates for on-board SPECT because of time constraints in the treatment room. Using 4-minute scans, mean localization errors were within 2 mm for superficial targets of 6:1 activity that were proximal to the detector trajectory and of at least 14 mm in diameter. Localization was significantly better (p < 0.05, Wilcoxon signed-rank test) with than without observer normalization and DRC at 5 of 6 superficial tumor sites. Observer normalization improved localization substantially for a target proximal to the much hotter heart. Localization error patterns were shown to be anisotropic and dependent on target position relative to the detector trajectory. Detector views of close approach and of minimal attenuation were predictive of directions with the smallest (magnitude) localization bias and precision. The detector trajectory had a substantial effect on localization performance. In scanner-acquired SPECT images, mean localization errors of a 22-mm-diameter superficial target were 0.8, 1.5, and 6.9 mm respectively using proximal 180°, 360°, and distal 180° detector trajectories, thus demonstrating the benefits of using a proximal 180° detector trajectory.</p><p>In conclusion, the potential performance characteristics of on-board SPECT were investigated using computer-simulation and real-detector studies. Mean localization errors < 2 mm were obtained for proximal, superficial targets with diameters >14 mm and of 6:1 activity relative to background using scan times of approximately 5 minutes. The observed direction-dependent localization errors are related to the detector trajectory and have important implications for radiation therapy. This works shows that parallel-hole SPECT could be useful for localizing certain biological targets.</p> / Dissertation

Prostate cancer is a worldwide health concern for men. Needle biopsy is the most definitive form of cancer diagnosis. Target-specific biopsies can be performed under magnetic resonance imaging (MRI) guidance. However, needle placements are often inaccurate due to intra-operative prostate motion and the lack of motion compensation techniques. As a result, malignant tumors can be missed, which in turn will lead to an increased number of repeated biopsies and delaying of treatment. To increase the needle targeting accuracy, intra-operative prostate motion and deformation need to be studied so that motion compensation techniques can be developed accordingly. This thesis intends to make three main contributions: 1. A comprehensive survey of the state-of-art in image-guided prostate needle placement interventions. 2. Retrospective clinical accuracy validation of a MRI-guided robotic prostate biopsy system that was used in the U.S. National Cancer Institute for over 6 years. A 3D-3D registration algorithm consists of an initial two-step rigid alignment followed by a B-spline deformable transform was developed to align the pre- and post-needle insertion images. A total of 90 biopsies from 24 patients were studied. The mean target displacement, needle placement error, and clinical biopsy error were 5.2, 2.5, and 4.3 mm, respectively. 3. Development of a multi-slice-to-volume registration for intra-operative target localization. The algorithm aligns the planning volume with three orthogonal image slices of the prostate acquired immediately before needle insertion. It consists of a rigid registration followed by a deformable step using only the prostate region. The algorithm was validated on 14 clinical images sets from Brigham and Women's Hospital in Boston, Massachusetts. All registration errors were well below the radius of a clinically significant tumour (5 mm), and are considered clinically acceptable. The results show that there was a substantial amount of biopsy error caused by prostate motion and deformation during MRI-guided biopsy. This error can be reduced by using quantitative imaging techniques for prostate registration and motion compensation. In particular, the multi-slice-to-volume registration algorithm demonstrated the feasibility of intra-operative target localization and motion compensation; which in turn may improve the quality of MRI-guided prostate interventions. / Thesis (Ph.D, Computing) -- Queen's University, 2014-03-01 11:45:55.8

Since World War I, the area of acoustic undersea warfare has witnessed several research activities targeting the development of advanced systems to accurately detect and localize underwater moving targets. One of the main categories of these systems is the passive sound navigation and ranging (SONAR) that searches for the location of the ships and submarines by listening to the radiated noise produced by their propellers, machinery, and flow dynamics. The performance of the passive sonar highly depends on the particular array signal processing algorithms used in practice. Presently, one of the main challenges is to accurately estimate the target direction of arrival (DOA) in severe underwater environments. This thesis is proposed to enhance the DOA estimation in two distinct applications. This first application is to improve the spatial resolution of the uniform linear towed arrays. This is done by applying new spatial extrapolation techniques called 2D- and 3D- fast orthogonal search (FOS) for both uniform linear and rectangular arrays, respectively. The presented methods show better performance than the conventional methods with respect to signal to noise ratio (SNR), number of snapshots and angular separation. Moreover it reduces the computational complexity required by the spatial extrapolation methods based on linear prediction approach. The other application concerns with developing a new DOA estimation that provides better spatial spectrum than the one provided by conventional beamforming (CBF) when a nonuniform linear array of directional frequency analysis and recording (DIFAR) sonobuoys is employed. The introduced technique or the so called fourth order cumulant beamforming (FOCBF) and shows an outstanding performance compared to CBF especially in low SNR. Furthermore, a warping FOC-BF (WFOC-BF) method obtained by augmenting a warping beamforming technique with FOC-BF is proposed to reduce the required computational complexity by FOC-BF while preserving the same performance. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2012-06-27 14:59:33.941

The subject of this thesis is the development of localization algorithms for target localization in wireless sensor networks using received signal strength (RSS) measurements or Quantized RSS (QRSS) measurements. In chapter 3 of the thesis, target localization using RSS measurements is investigated. Many existing works on RSS localization assumes that the shadowing components are uncorrelated. However, here, shadowing is assumed to be spatially correlated. It can be shown that localization accuracy can be improved with the consideration of correlation between pairs of RSS measurements. By linearizing the corresponding Maximum Likelihood (ML) objective function, a weighted least squares (WLS) algorithm is formulated to obtain the target location. An iterative technique based on Newtons method is utilized to give a solution. Numerical simulations show that the proposed algorithms achieves better performance than existing algorithms with reasonable complexity. In chapter 4, target localization with an unknown path loss model parameter is investigated. Most published work estimates location and these parameters jointly using iterative methods with a good initialization of path loss exponent (PLE). To avoid finding an initialization, a global optimization algorithm, particle swarm optimization (PSO) is employed to optimize the ML objective function. By combining PSO with a consensus algorithm, the centralized estimation problem is extended to a distributed version so that can be implemented in distributed WSN. Although suboptimal, the distributed approach is very suitable for implementation in real sensor networks, as it is scalable, robust against changing of network topology and requires only local communication. Numerical simulations show that the accuracy of centralized PSO can attain the Cramer Rao Lower Bound (CRLB). Also, as expected, there is some degradation in performance of the distributed PSO with respect to the centralized PSO. In chapter 5, a distributed gradient algorithm for RSS based target localization using only quantized data is proposed. The ML of the Quantized RSS is derived and PSO is used to provide an initial estimate for the gradient algorithm. A practical quantization threshold designer is presented for RSS data. To derive a distributed algorithm using only the quantized signal, the local estimate at each node is also quantized. The RSS measurements and the local estimate at each sensor node are quantized in different ways. By using a quantization elimination scheme, a quantized distributed gradient method is proposed. In the distributed algorithm, the quantization noise in the local estimate is gradually eliminated with each iteration. Simulations show that the performance of the centralized algorithm can reach the CRLB. The proposed distributed algorithm using a small number of bits can achieve the performance of the distributed gradient algorithm using unquantized data.

In passive target localization, source position is estimated by only using the source signal. In this thesis, position of a stationary target is estimated by using the data collected by a moving platform. Since the focus of the thesis is the location estimation, the parameters used for localization such as angle-of-arrival (AOA), time-difference-of-arrival (TDOA), Doppler frequency shift are assumed to be known. Different emitter localization methods are implemented in this thesis. Some of these methods are known in the literature and some are the modified or hybrid versions of these algorithms. Orthogonal Vector Estimator (OVE), Pseudolinear Estimator (PLE), Weighted Instrumental Variables Estimator (WIVE) and Maximum Likelihood Estimator (MLE) use only the AOA information. In MLE, Gauss Newton (GN) search algorithm is used to realize the search process effectively. AOA localization methods are also implemented together with the extended Kalman filter (EKF) realization. Doppler Shifted Frequency (DSF) based Least Squares (LS) and MLE are implemented which use Doppler frequency shift only. AOA-DSF combined hybrid algorithm is shown to perform better. LS and Maximum Likelihood (ML) TDOA localization methods are also implemented. AOA-DSF-TDOA combined hybrid algorithm is shown to perform better than the algorithms which use one type of parameter and AOA-DSF hybrid algorithm. Estimator performances are analyzed in this thesis. Error ellipsoid is a useful tool to evaluate an estimator

La connaissance de l'environnement marin est nécessaire pour un grand nombre d'applications dans le domaine de l'acoustique sous-marine comme la communication, la localisation et détection sonar et la surveillance des mammifères marins. Il constitue le moyen principal pour éviter les interférences néfastes entre le milieu naturel et les actions industriels et militaires conduites en zones côtières.Notre travail de thèse se place dans un contexte de sonar actif avec des fréquences allant de 1 kHz à 10 kHz pour des distances de propagations allant de 1 km à plusieurs dizaines de kilomètres. Nous nous intéressons particulièrement aux environnements de propagation grands fonds, à l'utilisation des antennes industrielles comme les antennes de flancs, les antennes cylindriques et les antennes linéaires remorquées, et à l'utilisation de signaux large bande afin de travailler avec des résolutions en distance et en vitesse très élevées. Le travail de recherche présenté dans ce mémoire est dédié à la recherche de nouveaux paramètres discriminants pour la classification de cible sous-marine en sonar actif et notamment à l'estimation de l'immersion instantanée.Cette étude présente : (1) les calculs de nouvelles bornes de Cramer-Rao pour la position d'une cible en distance en et en profondeur, (2) l'estimation conjointe de la distance et de l'immersion d'une cible à partir de la mesure des temps d'arrivées et des angles d'élévations sur une antenne surfacique et (3) l'estimation conjointe de la distance, de l'immersion et du gisement d'une cible à partir de la mesure des temps d'arrivées et des pseudo-gisements sur une antenne linéaire remorquée.Les méthodes développées lors de cette étude ont été validées sur des simulations, des données expérimentales à petite échelle et des données réelles en mer. / The knowledge of the marine environment is required for many underwater applications such as communications, sonar localization and detection, and marine mammals monitoring. It enables preventing harmful interference between the natural environment and industrial and military actions in coastal areas.This thesis work concentrates upton the context of active sonar with frequencies from 1 kHz to 10 kHz and long propagation ranges from 1 km to several tens of kilometers. We also concentrates upon deep water environment, the use of industrial arrays such as cylindrical arrays, flank arrays and linear towed arrays, and the use of large time-bandwidth signals in order to obtain high distance and speed resolutions. This research work is dedicated to the research of new features for the underwater target classification in active sonar, and specifically to the instantaneous target-depth estimation.This thesis presents: (1) calculations of new Cramer-Rao bounds for the target-position in range and in depth, (2) the joint estimation of the target-depth and the target-range from the arrival time and elevation angle measures with a surface array, (3) the joint estimation of the target-depth, the target-range and the target-bearing from the arrival time and pseudo-bearing angle measures with a linear towed array.The methods presented in this manuscript have been benchmarked on simulation, on reduced-scale experimental data and real marine data.

Unmanned Aerial Vehicles (UAVs) equipped with lightweight, inexpensive cameras have grown in popularity by enabling new uses of UAV technology. However, the video retrieved from small UAVs is often unwatchable due to high frequency jitter. Beginning with an investigation of previous stabilization work, this thesis discusses the challenges of stabilizing UAV based video. It then presents a software based computer vision framework and discusses its use to develop a real-time stabilization solution. A novel approach of estimating intended video motion is then presented. Next, the thesis proceeds to extend previous target localization work by allowing the operator to easily identify targets—rather than relying solely on color segmentation—to improve reliability and applicability in real world scenarios. The resulting approach creates a low cost and easy to use solution for aerial video display and target localization.

Visual sensor networks (VSNs) merge computer vision, image processing and wireless sensor network disciplines to solve problems in multi-camera applications in large surveillance areas. Although potentially powerful, VSNs also present unique challenges that could hinder their practical deployment because of the unique camera features including the extremely higher data rate, the directional sensing characteristics, and the existence of visual occlusions. In this dissertation, we first present a collaborative approach for target localization in VSNs. Traditionally; the problem is solved by localizing targets at the intersections of the back-projected 2D cones of each target. However, the existence of visual occlusions among targets would generate many false alarms. Instead of resolving the uncertainty about target existence at the intersections, we identify and study the non-occupied areas in 2D cones and generate the so-called certainty map of targets non-existence. We also propose distributed integration of local certainty maps by following a dynamic itinerary where the entire map is progressively clarified. The accuracy of target localization is affected by the existence of faulty nodes in VSNs. Therefore, we present the design of a fault-tolerant localization algorithm that would not only accurately localize targets but also detect the faults in camera orientations, tolerate these errors and further correct them before they cascade. Based on the locations of detected targets in the fault-tolerated final certainty map, we construct a generative image model that estimates the camera orientations, detect inaccuracies and correct them. In order to ensure the required visual coverage to accurately localize targets or tolerate the faulty nodes, we need to calculate the coverage before deploying sensors. Therefore, we derive the closed-form solution for the coverage estimation based on the "certainty-based detection" model that takes directional sensing of cameras and existence of visual occlusions into account. The effectiveness of the proposed collaborative and fault-tolerant target localization algorithms in localization accuracy as well as fault detection and correction performance has been validated through the results obtained from both simulation and real experiments. In addition, conducted simulation shows extreme consistency with results from theoretical closed-form solution for visual coverage estimation, especially when considering the boundary effect.

This dissertation is focused on developing the new target localization and the target velocity estimation methods for frequency-only multi-input, multi-output (MIMO) radar systems with widely separated antennas. If the frequency resolutions of the transmitted signals are enough, only the received frequencies and the Doppler shifts can be used to find the position of the target. In order to estimate the position and the velocity of the target, most multistatic radars or radar networks use multiple independent measurements from the target such as time-of-arrival (TOA), angle-of-arrival (AOA) and frequency-of-arrival (FOA). Although, frequency based systems have many advantages, frequency based target localization methods are very limited in literature because of the fact that highly non-linear equations are involved in solutions. In this thesis, alternative target localization and the target velocity estimation methods are proposed for frequency-only systems with low complexity. One of the proposed methods is able to estimate the target position and the target velocity based on the measurements of the Doppler frequencies. Moreover, the target movement direction can be estimated efficiently. This method is referred to as &quot / Target Localization via Doppler Frequencies - TLDF&quot / and it can be used for not only radar but also all frequency-based localization systems such as Sonar or Wireless Sensor Networks. Besides the TLDF method, two alternative target position estimation methods are proposed as well. These methods are based on the Doppler frequencies, but they requires the target velocity vector to be known. These methods are referred to as &quot / Target Localization via Doppler Frequencies and Target Velocity - TLD&amp / V methods&quot / and can be divided two sub-methods. One of them is based on the derivatives of the Doppler Frequencies and hence it is called as &quot / Derivated Doppler - TLD&amp / V-DD method&quot / . The second method uses the Maximum Likelihood (ML) principle with grid search, hence it is referred to as &quot / Sub-ML, TLD&amp / V-subML method&quot / . The more realistic signal model for ground based, widely separated MIMO radar is formed as including Swerling target fluctuations and the Doppler frequencies. The Cramer-Rao Bounds (CRB) are derived for the target position and the target velocity estimations for this signal model. After the received signal is constructed, the Doppler frequencies are estimated by using the DFT based periodogram spectral estimator. Then, the estimated Doppler frequencies are collected in a fusion center to localize the target. Finally, the multiple targets localization problem is investigated for frequency-only MIMO radar and a new data association method is proposed. By using the TLDF method, the validity of the method is simulated not only for the targets which are moving linearly but also for the maneuvering targets. The proposed methods can localize the target and estimate the velocity of the target with less error according to the traditional isodoppler based method. Moreover, these methods are superior than the traditional method with respect to the computational complexity. By using the simulations with MATLAB, the superiorities of the proposed methods to the traditional method are shown.

Cette thèse en ergonomie s’inscrit dans le cadre d’un projet de conception industrielle d’un système innovant d’e-santé (HADAGIO), développé par l’entreprise SESIN et permettant le maintien à domicile de personnes âgées fragiles. Son objectif appliqué a été de produire des recommandations ergonomiques permettant d’améliorer les interfaces du système proposé sous la forme d’un portail d’applications web afin de les rendre faciles à utiliser par des personnes âgées et, ainsi, favoriser l’acceptation finale du dispositif HADAGIO. Ce travail s’est intéressé à la tâche de localisation d’informations sur un écran et, plus particulièrement, au rôle des éléments de surface (couleur et niveau de détails) des icônes et libellés lexicaux sur les performances de réalisation de cette tâche par des personnes âgées. Cette tâche est en effet particulièrement difficile pour ces dernières qui obtiennent des performances de localisation moindres que celles des jeunes (temps de réaction et nombre d’erreurs plus importants). Des recommandations graphiques pour la conception d’interfaces du portail HADAGIO ont émergées de ce travail, et permettent de faciliter la tâche de localisation des informations pour des personnes âgées. / This thesis in ergonomics is part of an industrial design project of an innovative e-health system (HADAGIO), developed by the company SESIN and allowing home support frail elderly. Its goal was applied to produce ergonomic recommendations for improving the interfaces of the system proposed in the form of a web portal software to make them easier to use and thus promote the final acceptance HADAGIO the device.This work has focused on the task of locating information on a screen and, in particular, the role of perceptual features (color and detail) lexical icons and labels on achieving performance of this task by elders. This task is indeed particularly difficult for this people who get lower localization performances than young people (reaction times and a larger number of errors). The models proposed for the target location task assumes that the knowledge possessed by individuals on the appearance of the target to locate allow improved performance. Given that advancing age does not affect the process involving knowledge stored in memory (Top Down type) implemented in this task it was to determine what could be the color of the role and Details of the target level in the implementation of these processes at a location task information.Graphics recommendations for HADAGIO portal interface design have emerged from this work, and provide information to facilitate the localization task for the elderly.