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Cone-beam CT (CBCT) imaging is heavily being utilized in radiotherapy treatment as means of treating cancer patients. One of the platforms is the Varian On-Board Imager (oBI) where kilo-volts (kV) CBCT imaging is used. In this study, a model of the OBI is developed to simulate the two scan modes that are available, namely: Full-Fan (FF) and Half-Fan (HF) modes. By shifting the same set of 1024×768...
Interdigitated photoconductive (IPC) switches are convenient sources and detectors for terahertz (THz) time domain spectroscopy. However, reflection of the emitted or detected radiation within the device substrate can lead to echoes that inherently limits the spectroscopic resolution achievable. In this work, we design and realize low-temperature-grown-GaAs (LT-GaAs) IPC switches for THz pulse generation...
We present a mobile vehicle classification technique achieved by tracking two vehicle based Points of Interest (PoI) in multiple filter configurations to compose a vehicle specific 3D geometry. Using high fidelity physics based simulation we demonstrate the capability to classify the 3D geometries in the presence of noise by extracting vector magnitudes and angles as features. Additionally, we investigate...
The development of novel superconducting photon detectors requires the investigation of non-traditional materials to exploit their specific properties and realize novel/enhanced devices. Nd2−xCexCuO4±5 is a moderate high transition temperature cuprate superconductor exhibiting n-type conduction which properties can be changed by modifying its cerium and oxygen content. Ultra-thin films of this compound...
Amorphous silicon bolometers with different pixel patterns are investigated for far infrared detection. Devices with floating resonator structure are measured for resistances and temperature coefficient of resistance (TCR) values. The results show normal leg geometry has high TCR (∼ −4%/°C) and moderate resistance. Thus the pixel pattern is suitable for infrared detecting applications.
In this paper we propose a probabilistic approach for detecting and classifying urban road intersections from a moving vehicle. The approach is based on images from an onboard stereo rig; it relies on the detection of the road ground plane on one side, and on a pixel-level classification of the road on the other. The two processing pipelines are then integrated and the parameters of the road components,...
In paper the determination problem of the location of the moving unobserved armored trucks (tanks) (1+2) kilometers away is considered. Based on the seismic location method by use of 3D coordinates detection set the computational algorithm of determination of the bearing angle and distance to unobserved target are presented, and computational errors are estimated. Also, for the purpose of angle errors...
Image registration which is frequently required in Medical, Computer vision and remote sensing field is used to align two images geometrically. This paper presents efficient method for providing speedup and more accuracy in compared to current state of the art existing methods. This paper focuses on Feature detection using Harris detector which gives best result based on performance and has firm invariance...
In this paper, we consider ridge detection for multicomponent signal analysis. We introduce a new ridge detector based on a projection of the reassignment vector in a specific direction which is related to the geometry of the spectrogram magnitude. The ridge definition we introduce enables that of the basin of attraction associated with a ridge and then mode reconstruction. Simulations show better...
A critical task in corner detection in 2D images is on the distinction between a corner pixel and a pixel with a large gradient (i.e., an edge pixel). Imbalanced point detection was proposed to address this problem, where a corner pixel is characterized as a pixel with an imbalanced appearance, while an edge pixel has the opposite property. With extensive experiments, an imbalanced point detector...
Fish abundance estimation with the aid of visual analysis has drawn increasing attention based on the underwater videos from a remotely-operated vehicle (ROV). We build a novel fish tracking and counting system followed by tracking-by-detection framework. Since fish may keep entering or leaving the field of view (FOV), an offline trained deformable part model (DPM) fish detector is adopted to detect...
A series of small size 22Na point sources have been simulated using GATE, following the NEMA protocol, and applied to the geometry of a brain dedicated PET so-called MindView. The simulated scanner geometry is currently composed by one ring of 20 detector blocks with a distance of about 330 mm between opposite detectors. Each detector module includes a monolithic LYSO crystal of 50 × 50 × 20 mm3 and...
A new Maia detector is being currently developed, consisting of an array of 384 silicon drift detectors (SDDs), each having an area of 1 mm2. The detector features a new double metal scheme that supplies biases to the pixel SDD rings. All 384 anodes of SDDs are meant to be connected to individual electronic channels. This effort was motivated by the need of improving the energy resolution and the...
Muon scattering tomography techniques can be used to image the contents of an enclosed volume by measuring the scattering angle of cosmic ray muons as they pass through a volume using particle tracking detectors. The magnitude of the observed muon scatter varies with the density of the objects within a volume, therefore the technique is well suited to distinguishing dense (high-Z) materials from lower...
Compact ring diameter PET systems suffer degradation in spatial resolution with increasing radial offset due to the parallax error caused by depth of interaction (DOI) effects. In this work, we study the problem of optimizing layer thicknesses for a detector that uses a dual-layer offset (DLO) scintillator array. In this design, a half-crystal offset exists between the crystals in the front and back...
Now hemispherical geometry is used for designing insensitive to the hole transport single polarity CdZnTe detectors. In this work, theoretical consideration of the processes in semiconductor hemispherical detectors for low energy X-rays was considered. The formulae for the mean amplitude and the variance of the signal at the output of the semiconductor hemispherical detector were derived. It was shown...
Radiation imaging systems provide a wealth of information for analyzing quantities of interest (enumeration, strength, dimensions) of an uncharacterized source. This capability is useful, for example, when measuring plutonium powder “held up” in unknown locations at reprocessing facilities. Accurate models of the imager are required to infer the quantity of interest. This paper describes the modeling...
The next generation of organ specific Positron Emission Tomography (PET) scanners, e.g. for breast imaging, will use partial ring geometries. We propose a component-based Maximum-Likelihood (ML) estimation of normalisation factors for 3D PET data reconstruction applicable to partial ring geometries. This method is based on the Software for Tomographic Image Reconstruction (STIR) for full ring PET...
In this work we perform a preliminary investigation of a discretized natural pixel expansion set for image representation in optimization-based image reconstruction for X-ray computed tomography. In particular, we focus our attention on total variation regularized image reconstruction in pixel and discrete natural pixel expansion sets. The work is motivated by two observations: (1) under certain conditions,...
In the context of the development of a simultaneous SPECT/MRI system, we have previously proposed a multi-mini-slit-slat (MSS) collimator, with multiple sections of short slits in order to improve the angular sampling. The data can be reconstructed using a 3D reconstruction algorithm that models the collimator geometry. One drawback, however, is that the projection data obtained with this collimator...
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