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In the reconstruction, the misaligned geometry will cause streak artifacts which influence image quality. Here we propose a method to calibrate all the parameters simultaneously with the matrix form. In some cases, the relative position between the X-ray source and the detector is known and invariant, and then we can build a Cartesian coordinate system for the source and the detector. At the same...
In the past few years, several interesting developments in microstructured solid-state thermal neutron detectors have been pursued. These devices feature high aspect-ratio cavities, lled with neutron converter materials, so as to improve the neutron detection efciency with respect to coated planar sensors. In the framework of the INFN HYDE (HYbrid Detectors for neutrons) project, we have designed...
High-resolution CBμCT imaging requires complex mechanical configurations that need advanced calibration procedures in order to obtain the best image quality. This work proposes a workflow for the complete geometrical calibration and characterization of a cone beam micro-CT system. Our implementation modifies methods described in previous works with updated enhancements and increased degrees of freedom...
Given the complexity of the image reconstruction procedures for Compton Camera events, especially when a 3D image is required for distributed sources in space, a simple, direct algorithmic approach is presented in this work. The developed ComptonRec package carefully handles the geometry of the conic sections to accumulate ray density distribution in a user defined voxelized volume inside the specified...
THE medical imaging technologies and the industrial ones have benefitted from each other. For a baggage inspection for example, multiple-detector helical CT scanning technology has been deployed that was originally developed for a fast volumetric imaging of a patient in clinics. In a helical CT, the detector array and the x-ray source are rotating continuously in a gantry with the slip-ring technology,...
In this paper, the PET subsystem of the GE Discovery 690 PET/CT scanner is modeled in order to construct the system matrix which is a prerequisite for many iterative reconstruction methods. The system matrix, H is a representation of the projection of the object onto the scanner's detector. The projection of the image (I) onto detections (S) is thus represented as a linear equation, S = H I. Image...
In this paper, we propose an adaptive template for semantic labeling of indoor scene objects and estimating their oriented bounding facets (OBFs). The proposed adaptive template encodes prior geometric information of objects based on statistics of the training images. Given an input image, we utilize the adaptive template on the detected bounding boxes to initialize the raw labeling and OBF estimation...
We report MoSi superconducting nanowire single-photon detectors (SNPDs) with low polarization sensitivity over a 120 nm wavelength range, covering the standard fiber telecom wavelengths. Our models indicate that this low polarization sensitivity is consistent with the design geometry.
Oceanic turbulence causes distortions of the bounded beam waves propagating underwater. The most obvious effects are the beam spread and beam wandering. Propagation theory identifies two distinct measures of the beam spread: Long-Term (LT) beam spread when the beam size is measured in the fixed coordinate system, and the Short-Term (ST) beam spread when the beam size is measured relative to the instantaneous...
In this paper we present a system for the automated detection of multiple anatomies in computer tomography (CT) localizer images. The proposed method employs classification cascades for the fast and accurate localization of individual anatomies. In order to facilitate the joint localization of multiple anatomies, their geometric relations are described in terms of a probabilistic model. This gives...
We propose a three dimensional position measurement method employing planar photo detectors to calibrate a Spatial Augmented Reality system of unknown geometry. In Spatial Augmented Reality, projectors overlay images onto an object in the physical environment. For this purpose, the alignment of the images and physical objects is required. Traditional camera based 3D position tracking systems, such...
This paper presents a new approach of designing a n-in-n ATLAS pixel sensor shape inspired form golden ratio by using the golden ratio in the design of the multi guard rings structure. A new configuration is proposed in the goal of optimizing its layout parameter. The performance of the optimized guard rings structure is evaluated with TCAD simulation. It’s shown that the optimized structure related...
A tomographic methodology for inspection of TSV (Through Silicon Via) process wafers is developed by utilizing an X-ray source. In conventional X-ray computed tomography (CT), the scanning axis of X-ray source and detector is approximately parallel to the long axis of the phantom and perpendicular to the plane of X-ray source. However, because TSV projection data are captured by angling the phantom...
TORCH is a Cherenkov time-of-flight detector being developed as a particle identification system for the upgraded LHCb experiment. The DIRC-type detector is located at 10m distance from the interaction point with an area of 30m2 and is formed from 10mm thick synthetic amorphous fused silica plates. In this Cherenkov radiator the photons that propagate by total internal reflection to the plate edge...
Before the image reconstruction process takes place, emission data from a PET scanner must be corrected for scatter and changes for detector sensitivity. Normalization process should take care of the variations in the detector sensitivity. Because of the need of high statistics for large number of line-of-responses (LORs), component-based normalization method was implemented in the state-of-the-art...
We are developing a Point-Of-Care PET (POC-PET) imaging system platform that consists of one or more movable probe detectors in coincidence with a detector-array behind a patient. The probes are hand movable so that the operator can control the probe trajectory freely to achieve optimal coverage and sensitivity for patient-specific imaging tasks. This platform does not require a conventional full...
Foam materials saturated with neutron sensitive compounds are of interest as a viable replacement for 3He-based neutron detectors. Previous studies have shown the feasibility of 6LiF-saturated foam detectors as a valid replacement both experimentally and theoretically. However, the random geometry of foam material has previously limited the effective theoretical considerations for such materials to...
One of the challenging applications of PET is implementing it for in-beam PET, which is an in situ monitoring method for charged particle therapy. For this purpose, we previously proposed the world's first open-type geometries which we named OpenPET. For in-beam PET, careful designing and testing of detectors are important because secondary particles generated in a target degrade detector performance...
We aim at developing practical ways to measure the parameters necessary for data corrections and calibration of a PET scanner with variable geometry (ClearPEM), in order to achieve accurate quantitative images for a large range of imaging tasks using few phantom measurements. We used a decaying cylindrical phantom to determine calibration and dead time factors for a set of acquisition geometries that...
The ability to detect the presence of radioactive sources and Special Nuclear Materials (SNM) is of extreme importance for homeland security efforts. Today, we face terrorist threats in the form of explosive nuclear devices and Radiation Dispersal Devices (RDDs). The ability to remotely locate and identify the materials used to create these devices is imperative in the interdiction of terrorist threats...
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