- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Fast Modeling Methods for Estimating Imaging Performance of Whole Body Screening
摘要： Simulation of millimeter wave imaging system for whole body screening before a safety inspection manufactured is a challenging work. The conventional physical optics (PO) method is a proper high-frequency approximation method to solve the forward problem of imaging. In this letter, a modi?ed PO method is used to calculate not only metal scatterer but also non-metal dielectric medium. A ray tracing (RT) method and its modi?cation are proposed to further fast estimate the performance of multiple-input-multiple-output (MIMO) imaging system. The radiation pattern of transmitter or receiver is taken into account, then the rough imaging performance of arbitrary MIMO system on arbitrary human posture can be acquired in seconds to make the system design ?exible and convenient. The image reconstruction of the proposed method for a human body model with dielectric skin medium and metal pistol has demonstrated the applicability to real-life applications.
关键词： Millimeter wave imaging,concealed weapon detection (CWD),Image reconstruction,Physical optics (PO),Ray tracing (RT),Multiple-input-multiple-output (MIMO)
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [AIP Publishing LLC NEW OPERATIONAL TECHNOLOGIES (NEWOT’2015): Proceedings of the 5th International Scientific Conference ?New Operational Technologies? - Tomsk, Russia (29–30 September 2015)] - X-ray microtomographic scanners
摘要： The article studies the operating procedures of an X-ray microtomographic scanner and the module of reconstruction and analysis 3D-image of a test sample in particular. An algorithm for 3D-image reconstruction based on image shadow projections and mathematical methods of the processing are described. Chapter 1 describes the basic principles of X-ray tomography and general procedures of the device developed. Chapters 2 and 3 are devoted to the problem of resources saving by the system during the X-ray tomography procedure, which is achieved by preprocessing of the initial shadow projections. Preprocessing includes background noise removing from the images, which reduces the amount of shadow projections in general and increases the efficiency of the group shadow projections compression. In conclusion, the main applications of X-ray tomography are presented.
关键词： non-destructive testing,shadow projections,3D-image reconstruction,data compression,X-ray microtomography
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Robust Super-Resolution Image Reconstruction Method for Geometrically Deformed Remote Sensing Images
摘要： Due to the limitations of imaging sensors, remote sensing images often have limited resolution. To address this issue, various super-resolution (SR) image reconstruction techniques have been developed to reconstruct a high-resolution image from a sequence of low-resolution, noisy and blurry observations. In this paper, we propose an efficient super-resolution image reconstruction method for geometrically deformed remote sensing images, based on the nonlocal total variation (NLTV) regularization. The proposed minimization problem is solved by a fast primal-dual algorithm. Numerical experiments demonstrate the performance of the proposed method.
关键词： super-resolution image reconstruction,Remote sensing images,primal-dual algorithm
更新于2025-09-10 09:29:36
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Repeatability of <sup>18</sup> F-FDG PET Radiomic Features: a Phantom Study to Explore Sensitivity to Image Reconstruction Settings, Noise, and Delineation Method
摘要： Background: 18F-fluoro-2-deoxy-D-Glucose positron emission tomography (18F-FDG PET) radiomics has the potential to guide the clinical decision making in cancer patients, but validation is required before radiomics can be implemented in the clinical setting. The aim of this study was to explore how feature space reduction and repeatability of 18F-FDG PET radiomic features are affected by various sources of variation such as underlying data (e.g. object size and uptake), image reconstruction methods and settings, noise, discretization method, and delineation method.
关键词： 18F-FDG PET/CT radiomic features,delineation,image reconstruction settings
更新于2025-09-10 09:29:36
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Sensor resolution enhancement for remote imaging by synthesizing mask-based camera array images
摘要： In this paper, we propose an architecture based on camera array with masks to enhance the sensor resolution of remote imaging system. The sensor resolution is enhanced by multiplexing the sensor images of each camera, in which the angular resolution bandwidth is converted using masks to expand the spatial resolution bandwidth. The improvement of the sensor resolution depends on the number of cameras in the array. The theory of improving the sensor resolution is discussed both in Fourier domain and spatial domain. We verify resolution enhancement of the architecture by ray-tracing imaging simulation. A simulation model is built to verify the resolution-enhancing ability of the camera array architecture. From each camera in the array, we get a resolution-limited image. The reconstructed image is synthesized from all the images of the cameras. The post-synthesized image has finer information details compared with the images of each camera. The resolution improvement varies with the object distance. The optimal resolution improvement of the reconstructed image is equal to the total sensor pixels of the camera array.
关键词： Image reconstruction,Light field,Remote imaging,Resolution enhancement
更新于2025-09-10 09:29:36
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Total image constrained diffusion tensor for spectral computed tomography reconstruction
摘要： Photon counting detector (PCD)-based spectral computed tomography (CT) is a promising imaging technique that enables high energy resolution imaging with narrow energy bins. However, the image quality is degraded because the number of photons in each energy bin is less than the number of photons in the full spectrum. To reconstruct high quality spectral CT images with narrow energy bins, we developed a total image constrained diffusion tensor (TICDT) for statistical iterative reconstruction (SIR) based on a penalized weighted least-squares (PWLS) principle, which is called “PWLS-TICDT.” Specifically, TICDT uses supplementary information from a high-quality total image as a structural prior for SIR, so that the narrow energy bin image can be enhanced, while some primary features are preserved. We also developed an alternating minimization algorithm to solve the associated objective function. We conducted qualitative and quantitative studies to validate and evaluate the PWLS-TICDT method using digital phantoms and preclinical data. Results from both numerical simulation and real PCD data studies show that the proposed PWLS-TICDT method achieves noticeable gains over competing methods in terms of suppressing noise, detecting low contrast objects, and preserving resolution. More importantly, the multi-energy images reconstructed by PWLS-TICDT method can generate more accurate basis material decomposition results than the other methods.
关键词： Photon counting detector,Image reconstruction,Diffusion tensor,Spectral CT
更新于2025-09-10 09:29:36
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A Higher-Order Polynomial Method for SPECT Reconstruction
摘要： Existing single-photon emission computed tomography (SPECT) reconstruction methods are mostly based on discrete models that may be viewed as piecewise constant approximations of a continuous data acquisition process. Due to low accuracy order of piecewise constant approximations, a traditional discrete model introduces irreducible model errors which are a bottleneck of the quality improvement of reconstructed images in clinical applications. To overcome this drawback, we develop a higher-order polynomial method for SPECT reconstruction. Specifically, we represent the data acquisition of SPECT imaging by using an integral equation model, approximate the solution of the underlying integral equation by higher-order piecewise polynomials leading to a new discrete system and introduce two novel regularizers for the system, by exploring the a priori knowledge of the radiotracer distribution, suitable for the approximation. The proposed higher-order polynomial method outperforms significantly the cutting edge reconstruction method based on a traditional discrete model in terms of model error reduction, noise suppression and artifact reduction. In particular, the coefficient of variation of images reconstructed by the piecewise linear polynomial method is reduced by a factor of 10 in comparison to that of a traditional discrete model-based method.
关键词： Image reconstruction,Nuclear imaging,Noise and artifact reduction
更新于2025-09-10 09:29:36
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Membership Function-Weighted Non-Linear Fitting Method for Optical-Sensing Modeling and Reconstruction
摘要： Imprecise measurements present universally due to variability in the measurement error. We devised a very simple membership function to evaluate fuzzily the quality of optical sensing with a small dataset, where a normal distribution cannot be assumed. The proposed membership function was further used as a weighting function for non-linear curve fitting under expected mathematical model constraints, namely the membership function-weighted Levenberg–Marquardt (MFW-LM) algorithm. The robustness and effectiveness of the MFW-LM algorithm were demonstrated by an optical-sensing simulation and two practical applications. (1) In laser-absorption spectroscopy, molecular spectral line modeling was greatly improved by the method. The measurement uncertainty of temperature and pressure were reduced dramatically, by 53.3% and 43.5%, respectively, compared with the original method. (2) In imaging, a laser beam-profile reconstruction from heavy distorted observations was improved by the method. As the dynamic range of the infrared camera increased from 256 to 415, the detailed resolution of the laser-beam profiles increased by an amazing 360%, achieving high dynamic-range imaging to capture optical signal details. Therefore, the MFW-LM algorithm provides a robust and effective tool for fitting a proper physical model and precision parameters from low-quality data.
关键词： non-linear curve fitting,sensing modeling and reconstruction,image reconstruction-restoration,optical-sensing signal processing,laser-absorption spectroscopy
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - SPECT Reconstruction and Analysis for the Inspection of Spent Nuclear Fuel
摘要： A gamma-emission-tomography (GET) system for the inspection of spent nuclear fuel (SNF) has been developed and tested on multiple fuel types. This tool can be used for verification of the integrity of an assembly and consistency with fissile-material content. Parallel-beam line integrals are measured by a discrete array of CdZnTe detectors that view the fuel through a 1.5mm wide by 100mm thick tungsten collimator. Detectors and electronics are on a rotating platform within a watertight stainless steel torus. During operation, the system is underwater and fuel is lowered through the center of the torus and held stationary as data are collected. Tomographic data collection requires a time on the order of minutes. In field experiments, data with count rates in the range of 50kcps to >500kcps per pixel have been recorded. In the reconstructed images, missing or replaced pins in all assembly types can be visually discriminated in the lattice of fuel pins. Automated detection of missing/replaced pins is the metric used for determination of optimal processing steps. Effectiveness of reconstruction and data-processing tools is measured by a tools ability to improve performance on the pin-discrimination task. This paper describes the data preprocessing, image reconstruction, image analysis, and performance evaluation of this system.
关键词： gamma-ray emission tomography,image quality metrics,safeguards,attenuation correction,image reconstruction,spent nuclear fuel
更新于2025-09-09 09:28:46
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Terahertz two-pixel imaging based on complementary compressive sensing
摘要： A compact terahertz (THz) imaging system based on complementary compressive sensing has been proposed using two single-pixel detectors. By using a mechanical spatial light modulator, sampling in the transmission and re?ection orientations was achieved simultaneously, which allows imaging with negative mask values. The improvement of THz image quality and anti-noise performance has been veri?ed experimentally compared with the traditional reconstructed image, and is in good agreement with the numerical simulation. The demonstrated imaging system, with the advantages of high imaging quality and strong anti-noise property, opens up possibilities for new applications in the THz region.
关键词： image reconstruction techniques,terahertz imaging,spatial light modulators
更新于2025-09-09 09:28:46