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This paper reports on the geometric calibration procedure of a bench-top, high-speed, and continuous-rotation preclinical computed tomography (CT) scanner that has been developed at our institution. A full 13-parameter model of the image formation process is described. Once calibrated, the model is used to modify projection data sets — the standardization operation — so that they appear to come from...
Most methods to improve the performance of CZT detectors focus on the single polarity charge sensitivity technology, such as Coplanar grid, small pixel effect and so on. Our new design of line anode geometry also applies the single polarity charge sensitivity. With the simple electrode geometry the energy resolution of a 10mm*10mm*10mm CZT detector was improved to 2.17% for 662keV gamma rays. In order...
Dedicated positron imagers with dual plane detectors for breast get high scatter fraction (SF) due to 3D data acquisition. In this study, we investigate the contribution of scatter from each breast and body outside of FOV, and its effects on lesion visibility. Beam stoppers (BSs) were designed to estimate the scatter distribution. All the data in this study were simulated using GATE. The FOV of this...
The aim of this work was to propose an analytic reconstruction of two-dimensional CT images in the presence of both patient motion and truncation of the projection data. The proposed method is based on the method of differentiated backprojection with Hilbert filtering (DBP-H). There is a variant of this algorithm which suits our purpose because it begins with a simple backprojection of the unprocessed...
A precise knowledge of the geometry is always pivotal to a x-ray imaging system, such as computed tomography, digital x-ray tomosynthesis and computed laminography. A typical tomosynthesis system is referred to as the relative positions between the focal spots of the x-ray source and the detector, the object remains in a fixed position above the detector and the x-ray tube emits x-ray beams in the...
The OpenPET is our original idea that realizes the world's first open-type 3D PET scanner for PET-image guided particle therapy such as in situ dose verification and direct tumor tracking. Even with a full-ring geometry, the OpenPET has an open gap between its 2 detector rings through which the treatment beam passes. Following our initial 2008 proposal, we developed a small prototype in 2010 to show...
In this paper we describe an approach to automatically improving the efficiency of soft cascade-based person detectors. Our technique addresses the two fundamental bottlenecks in cascade detectors: the number of weak classifiers that need to be evaluated in each cascade, and the total number of detection windows to be evaluated. By simply observing a soft cascade operating on a scene, we learn scale...
In this paper, we show how pedestrian detection accuracy and efficiency can be improved for static surveillance cameras using scene context and temporal non-maximal suppression. First, using the geometry of the scene, we derive the relationship between height in the image with respect to height in the real-world. This relationship is used to learn the range of scales to evaluate for potential detections...
In this paper we present a method for aligning shredded document pieces based on outer contours and content-based prior information. Our approach relies on domain-specific knowledge that document pieces must complement each other when aligned correctly. Building on this intuition we propose a variant of MSAC (M-estimator SAmple Consensus) to estimate an hypothesis that recovers the spatial relationship...
An autonomous car must have a robust perception system to navigate safely in urban streets. An important issue of environment perception is the road (navigable area) detection and the identification of the road geometry. The road geometry information can be used to determine the vehicle control according to the street and also for topological localization. Existing road geometry identifiers only work...
In 2017 year collider from project NICA is going to start working. Needs software for it correct work and data handling, in particular, for visualization particle tracks and geometry of Many Purpose Detector. This software was realized. It based on FROG package.
The solenoid type magnetic field detector modeling was made. The problem of the maximum domain size obtaining with the high degree magnetic field homogeneous is considered. The geometrical form of the iron core and current coil were taken into account, when the optimization was made. The different detector configurations were obtained and they comparisons were made.
The use of a light source as a beacon is advantageous for the guidance and control of Unmanned Underwater Vehicles (UUVs). This approach allows a follower UUV to determine its relative pose (position and orientation) using low-cost commercial off the shelf (COTS) hardware (e.g., metal halide light sources). In order to design an effective detector unit for the follower UUV and predict its performance,...
A method for partial near-duplicate retrieval in random images is proposed and evaluated. Unlike the majority of existing methods, it is based on matching individual keypoints only (i.e. no analysis/verification of configuration constraints). The proposed description of keypoints incorporates affine-invariant representation of keypoint bundles (photometric and geometric properties of neighboring keypoints)...
Wide-baseline matching focussing on problems with extreme viewpoint change is considered. We introduce the use of view synthesis with affine-covariant detectors to solve such problems and show that matching with the Hessian-Affine or MSER detectors outperforms the state-of-the-art ASIFT [19]. To minimise the loss of speed caused by view synthesis, we propose the Matching On Demand with view Synthesis...
The limited detector size of cone-beam CT (CBCT) imaging devices restricts their axial coverage. We previously found in simulation studies that the useful axial coverage could be extended by using two circular scans at different axial positions. By combining this dual scan with iterative reconstruction techniques, we can increase the useful field of view while providing better image quality in the...
The performance of the CMS electromagnetic calorimeter (ECAL) has been continuously monitored during LHC running. The evolution of this performance is a critical issue for the future, in particular for High-Luminosity LHC (HL-LHC) operation which is planned for 2022 and beyond. Work has started to assess the need for possible changes to the detector in order to maintain adequate performance in the...
An image reconstruction algorithm for rectangular PET scanner was developed using distance-driven projections. The geometrical sensitivity of the tubes of response in rectangular geometry was derived under the assumption that the detector area is very small relative to the distances between the detectors. Linograms were used for the histograms of coincidences between parallel panels, and “orthograms”...
The current Positron Emission Tomography (PET)s design is towards improving sensitivity. In this paper, we investigated the advantage of establishing an entire-body PET scanner. Despite of its high cost production, entire-body DOI PET scanners were expected to offer many benefits such as shorter time and dynamic PET acquisition, higher sensitivity and NECR. We simulated sensitivity and NECR test for...
An alternative detector design for Small Angle Neutron Scattering (SANS) applications is currently under development at the European Spallation Source (ESS). Given the unavailability and high price of 3He, this detector design utilizes gaseous detectors with 10B as neutron converter and is ideally suited for a SANS instrument at the ESS. The novel aspects of the geometry, exploiting the properties...
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