Extents and limits of radioscopic detection of nuclear materials in cargo containers with two megavoltage energy barriers

The megavoltage X-ray technology is utilized for detecting nuclear materials in cargo containers. Interlaced response is obtained by switching rapidly between 6MeV and 9 MeV beams. It is known that the ratio of penetration levels of cargo contents taken at nominal and dual energies provides the information about atomic numbers of materials, and thus can also indicate the threat group. However, the identification is not straightforward if combinations of materials are present. The latter can lead to misdetections. It is imperative to know what are the extent and the limit of the currently employed technology, and how to carry out the inspection in real-time by balancing the human involvement and the computer assistance. We have performed experiments with Linatron K9, analyze data and conclude on an efficient system configuration. The following are addressed: (a) visualization the contents to produce an image suitable for the visual analysis, and (b) prompting the custom personnel on the presence and the location of suspicious objects

Nonlinear Adaptive Diffusion Models for Image Denoising

Most of digital image applications demand on high image quality. Unfortunately, images often are degraded by noise during the formation, transmission, and recording processes. Hence, image denoising is an essential processing step preceding visual and automated analyses. Image denoising methods can reduce image contrast, create block or ring artifacts in the process of denoising. In this dissertation, we develop high performance non-linear diffusion based image denoising methods, capable to preserve edges and maintain high visual quality. This is attained by different approaches: First, a nonlinear diffusion is presented with robust M-estimators as diffusivity functions. Secondly, the knowledge of textons derived from Local Binary Patterns (LBP) which unify divergent statistical and structural models of the region analysis is utilized to adjust the time step of diffusion process. Next, the role of nonlinear diffusion which is adaptive to the local context in the wavelet domain is investigated, and the stationary wavelet context based diffusion (SWCD) is developed for performing the iterative shrinkage. Finally, we develop a locally- and feature-adaptive diffusion (LFAD) method, where each image patch/region is diffused individually, and the diffusivity function is modified to incorporate the Inverse Difference Moment as a local estimate of the gradient. Experiments have been conducted to evaluate the performance of each of the developed method and compare it to the reference group and to the state-of-the-art methods

Разработка адаптивного метода оценки характеристик инспекционных досмотровых комплексов с функцией распознавания материалов объектов контроля

Цель - исследование влияния флуктуаций параметров пучка тормозного излучения от импульса к импульсу на качество распознавания материалов методом дуальных энергий, разработка способа оценки флуктуаций параметров пучка и включение его в алгоритм распознавания материалов и экспериментальная проверка применимости его на практике.to study the influence of fluctuations in the parameters of the bremsstrahlung beam from pulse to pulse on the quality of the recognition of materials by the dual energy method, to develop a method for estimating the fluctuations of the beam parameters and to include it in the algorithm for recognizing materials and to experimentally verify its applicability in practic

Разработка адаптивного метода оценки характеристик инспекционных досмотровых комплексов с функцией распознавания материалов объектов контроля

Цель - исследование влияния флуктуаций параметров пучка тормозного излучения от импульса к импульсу на качество распознавания материалов методом дуальных энергий, разработка способа оценки флуктуаций параметров пучка и включение его в алгоритм распознавания материалов и экспериментальная проверка применимости его на практике.to study the influence of fluctuations in the parameters of the bremsstrahlung beam from pulse to pulse on the quality of the recognition of materials by the dual energy method, to develop a method for estimating the fluctuations of the beam parameters and to include it in the algorithm for recognizing materials and to experimentally verify its applicability in practic

Optical network-on-chip architectures and designs

As indicated in the latest version of ITRS roadmap, optical wiring is a viable interconnection technology for future SoC/SiC/SiP designs that can provide broad band data transfer rates unmatchable by the existing metal/low-k dielectric interconnects. In this dissertation study, a set of different optical interconnection architectures are presented for future on-chip optical micro-networks. Three Optical Network-on-Chip (ONoC) architectures, i.e., Wavelength Routing Optical Network-on-Chip (WRON), Redundant Wavelength Routed Optical Network (RDWRON) and Recursive Wavelength Routed Optical Network (RCWRON) are proposed. They are fully connected networks designed based on passive switching Microring Resonator (MRR) optical switches. Given enough different routing optical wavelengths, between any two nodes in the system a bi-directional communication channel can be built. WRON, RDWRON and RCWRON share the similar network structure with different specialties that fit to different applications. A new topology of packet switching NoC architecture, i.e., Quartered Recursive Diagonal Torus (QRDT) is proposed. It is designed by overlaying diagonal torus. Due to its small diameter and rich routing recourses, QRDT leads to highly scalable NoCs. By combining WRON\u27s interconnection property and QRDT\u27s network topology, a group of 2D-Torus based Packet Switching ONoC (TON) architectures is proposed. The TON is further refined to a generalized open-topology ONoC architecture, called Generalized 2D-Torus-based Optical Network-on-Chip (GTON). The communication protocol in TON is packet switching. The advantages of GTON stem from Wavelength Division Multiplexing (WDM), Direct Optical Channel (DOC) and MRR passive switching. As result, GTON architecture is highly scalable, has an ultra-high bandwidth, consumes a low power, and supports fault-tolerant routing. The work includes other issues such as channel design, analyses of the transmission power loss and the buffer

On-board three-dimensional object tracking: Software and hardware solutions

We describe a real time system for recognition and tracking 3D objects such as UAVs, airplanes, fighters with the optical sensor. Given a 2D image, the system has to perform background subtraction, recognize relative rotation, scale and translation of the object to sustain a prescribed topology of the fleet. In the thesis a comparative study of different algorithms and performance evaluation is carried out based on time and accuracy constraints. For background subtraction task we evaluate frame differencing, approximate median filter, mixture of Gaussians and propose classification based on neural network methods. For object detection we analyze the performance of invariant moments, scale invariant feature transform and affine scale invariant feature transform methods. Various tracking algorithms such as mean shift with variable and a fixed sized windows, scale invariant feature transform, Harris and fast full search based on fast fourier transform algorithms are evaluated. We develop an algorithm for the relative rotations and the scale change calculation based on Zernike moments. Based on the design criteria the selection is made for on-board implementation. The candidate techniques have been implemented on the Texas Instrument TMS320DM642 EVM board. It is shown in the thesis that 14 frames per second can be processed; that supports the real time implementation of the tracking system under reasonable accuracy limits

Совершенствование коллиматоров для систем сканирующей цифровой радиографии

Исследовано влияние конструкции и параметров коллиматоров на качество систем цифровой радиографии и на основе проведённых исследований разработаны рекомендации по совершенствованию коллиматоров для систем цифровой радиографии и рентгеновской вычислительной томографии. Предложена и апробирована методика оценки влияния излучения, рассеянного в объекте контроля, на качество контроля методами цифровой радиографии и рентгеновской вычислительной томографии. Разработан алгоритм и программа моделирования переноса рентгеновского излучения в геометрии ограничения широкого пучка методом Монте-Карло. Произведено сравнение результатов вычислительного и натурного моделирования.The effect of the design and parameters of collimators on the quality of digital radiography systems was investigated and recommendations on the improvement of collimators for digital radiography and X-ray computed tomography were developed on the basis of the conducted studies. A technique for estimating the effect of radiation scattered in a monitoring object on the quality of control by digital radiography and X-ray computed tomography is proposed and tested. An algorithm and a program for simulating the transfer of X-ray radiation in the geometry of the restriction of a broad beam by the Monte Carlo method is developed. The results of computational and full-scale modeling are compared

Radioscopic Inspection of Cargo Containers with Megavoltage Energy Barriers

To perform the inspection of cargo containers the radioscopic screening is performed by switching between 6 and 9 MeV of boundary energies as rapidly as 200 times per second and measuring the penetration levels in the contents of cargo. This technology facilitates the material identification via the analyses of the ratios of signals obtained at nominal and dual energies, which are 6 and 9 MeV, respectively. The techniques are developed for (a) visualizing the contents to produce an image suitable for fast inspection by a human operator, and for (b) prompting the custom personnel about the location of suspicious objects. Specifically, nuclear materials are of interest. The experiments have been conducted with Linatron K9 device designed by Varian Security and Inspection Products. The capabilities are demonstrated for detection of objects of interests for the steel shields of 10 inches of thickness