- 标题
- 摘要
- 关键词
- 实验方案
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Scalable Bayesian Uncertainty Quantification in Imaging Inverse Problems via Convex Optimization
摘要： We propose a Bayesian uncertainty quanti?cation method for large-scale imaging inverse problems. Our method applies to all Bayesian models that are log-concave, where maximum a posteriori (MAP) estimation is a convex optimization problem. The method is a framework to analyze the con?dence in speci?c structures observed in MAP estimates (e.g., lesions in medical imaging, celestial sources in astronomical imaging), to enable using them as evidence to inform decisions and conclusions. Precisely, following Bayesian decision theory, we seek to assert the structures under scrutiny by performing a Bayesian hypothesis test that proceeds as follows: ?rst, it postulates that the structures are not present in the true image, and then seeks to use the data and prior knowledge to reject this null hypothesis with high probability. Computing such tests for imaging problems is generally very di?cult because of the high dimensionality involved. A main feature of this work is to leverage probability concentration phenomena and the underlying convex geometry to formulate the Bayesian hypothesis test as a convex problem, which we then e?ciently solve by using scalable optimization algorithms. This allows scaling to high-resolution and high-sensitivity imaging problems that are computationally una?ordable for other Bayesian computation approaches. We illustrate our methodology, dubbed BUQO (Bayesian Uncertainty Quanti?cation by Optimization), on a range of challenging Fourier imaging problems arising in astronomy and medicine. MATLAB code for the proposed uncertainty quanti?cation method is available on GitHub.
关键词： Bayesian inference,inverse problems,image processing,hypothesis testing,uncertainty quanti?cation,convex optimization
更新于2025-09-19 17:15:36
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An alumina rotary kiln monitoring system based on flame image processing
摘要： In order to monitor the combustion condition and improve the product material quality, a digital image acquisition and processing method is adopted in alumina-sintering process. Two digital properties of flame grade and material grade are obtained by image data analyzing and smooth filtering, which provide reliable reference for operational optimization and automatic control of rotary kilns. This image acquisition system improves the operation of kiln effectively and reduces the working intensity and the manufacture cost.
关键词： flame analyzing,Rotary kiln,image processing,sintering process,monitoring system
更新于2025-09-19 17:15:36
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BaB8O12F2: a promising deep-UV birefringent material
摘要： Seismic prediction has been a huge challenge because of the great uncertainties contained in the seismic data. Deep learning (DL) has been successfully applied in many fields and brought revolutionary changes, such as computer vision and natural language processing. The traditional artificial neural networks have been studied to improve the accuracy and resolution of seismic prediction for years, but not DL. In this paper, we develop a new architecture for seismic reservoir characterization based on the DL technique. We apply the convolutional neural network (CNN), which is a DL framework, to predict lithology and have achieved better results compared with traditional methods. We also propose to use continuous wavelet transforms (CWTs) to get a time–frequency spectrum for neural networks. CWTs help to make full use of the frequency content of the post-stack seismic data. According to the difference in the convolution layers and the organization of the input data, we propose four DL architectures for seismic lithology prediction, namely the deep neural networks (DNNs), the CNNs, the CWT-DNNs and the CWT-CNNs. All of these four architectures are applied in the case study. The final results on blind wells, profile and horizontal slice show that CWT-CNN models have the best performance on post-stack seismic lithology prediction. CWT maps contain more information about thinner layers and convolution layers are better at feature extraction from CWT maps. The CWT-CNN model has higher accuracy and resolution, especially on medium and thin layer prediction.
关键词： Wavelet transform,Neural networks,Asia,Image processing
更新于2025-09-19 17:15:36
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Research on the Application of Fast-steering Mirror in Stellar Interferometers
摘要： In stellar interferometers, the fast-steering mirror (FSM) is widely utilized to correct the wavefront tilt caused by the atmospheric turbulence and internal instrumental vibration, because of its high resolution and fast response frequency. In this study, the non-coplanar error between the FSM and the actuator deflection axis introduced by the manufacturing, assembly, and adjustment is analyzed systematically. Via a numerical method, the additional optical path difference (OPD) caused by the above factors is studied, and its effect on the fringe tracking accuracy of a stellar interferometer is also discussed. On the other hand, the starlight parallelism between the beams of two arms is one of the main factors for the loss of fringe visibility. By analyzing the influence of wavefront tilt caused by the atmospheric turbulence on fringe visibility, a simple and efficient real-time correction scheme of starlight parallelism is proposed based on a single array detector. The feasibility of this scheme is demonstrated by a laboratory experiment. The results show that after the correction of fast-steering mirror, the starlight parallelism meets preliminarily the requirement of a stellar interferometer on the wavefront tilt.
关键词： atmospheric effects,techniques: image processing,stars: imaging,instrumentation: interferometers,techniques: interferometric
更新于2025-09-19 17:15:36
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Experimental demonstration of imaging hidden objects in opaque liquid-based media by fusion of single-shot multiview polarized and unpolarized speckle images
摘要： Turbid water-based liquids are common scattering media within which imaging objects is challenging, since scattering particles of various origins and sizes may cause severe image degradation, resulting in poor object recovery and resolution. Therefore, counteracting the nontrivial effects of light scattering is a primary challenge, limiting the utility of optical imaging within liquid media. In this work, we sought to circumvent the optical degradation in turbid liquid media and to recover high-quality images of hidden objects by averaging polarized speckle images projected from several directions through a lens array. Inspired by astronomy imaging techniques, the averaging process utilized a Shift-and-Add (SAA) algorithm developed to reconstruct atmospherically-degraded solar images. Both linear and circular polarization strategies were then applied to further improve image reconstruction. Experiments were carried out using two targets, each having a distinct geometrical shape, embedded within turbid liquid media comprising a range of dilutions of commercially available cow’s milk in seawater. The media were irradiated with a polarized laser beam, after which multiple polarized speckled images were captured with a CCD camera. Offline, images were first shifted to a common center and then fused, using the SAA algorithm, to yield reconstructed images of each hidden object. Quantitative image quality metrics, including SNR, entropy, and sharpness were applied to evaluate quality of the reconstructed images. The reconstructed images obtained demonstrate successful adaptation of our methodology for the identification of hidden objects within turbid media. To the best of our knowledge, this is the first report to demonstrate successful imaging of hidden object images within turbid liquid media by averaging multiple polarized speckle projections.
关键词： Linear and circular polarization,Imaging through turbid water,Lens array,Multiple polarized speckle projections,Image processing
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE Globecom Workshops (GC Wkshps) - Waikoloa, HI, USA (2019.12.9-2019.12.13)] 2019 IEEE Globecom Workshops (GC Wkshps) - Free Space Optical Communication on UAV-Assisted Backhaul Networks: Optimization for Service Time
摘要： Distance functions are at the core of important data analysis and processing tools, e.g., PCA, classification, vector median filter, and mathematical morphology. Despite its key role, a distance function is often used without careful consideration of its underlying assumptions and mathematical construction. With the objective of identifying a suitable distance function for hyperspectral images so as to maintain the accuracy of hyperspectral image processing results, we compare existing distance functions and define a suitable set of selection criteria. Bearing in mind that the selection of distance functions is highly related to the actual definition of the spectrum, we also classify the existing distance functions based on how they inherently define a spectrum. Theoretical constraints and behavior, as well as numerical tests are proposed for the evaluation of distance functions. With regards to the evaluation criteria, Euclidean distance of cumulative spectrum (ECS) was found to be the most suitable distance function.
关键词： multidimensional signal processing,Image processing
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Pulsed Power & Plasma Science (PPPS) - Orlando, FL, USA (2019.6.23-2019.6.29)] 2019 IEEE Pulsed Power & Plasma Science (PPPS) - Electro-Optical Measurement of Electric Fields for Pulsed Power Systems
摘要： An RF argon plasma jet has been explored using high-speed camera imaging at 10 000 frames/s. Small variations of gas ?ow and/or RF power lead to instabilities of the ?lament movement. Two types of instabilities have been observed depending on the interrelated azimuthal velocities of ?laments. In the case of antiparallel ?lament velocities, one ?lament is collapsing and fuses with the other ?lament, while the collapsing ?lament exhibits a striated structure. In the case of parallel velocities, both ?laments establish a symmetric con?guration and rotate with constant velocity in the jet. Spatially and temporally resolved features are visualized with a time-colored stroboscopic image.
关键词： plasma stability,Image processing,plasma materials processing
更新于2025-09-19 17:13:59
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Optimal Cleaning Scheduling for Photovoltaic Systems in the Field Based on Electricity Generation and Dust Deposition Forecasting
摘要： An RF argon plasma jet has been explored using high-speed camera imaging at 10 000 frames/s. Small variations of gas ?ow and/or RF power lead to instabilities of the ?lament movement. Two types of instabilities have been observed depending on the interrelated azimuthal velocities of ?laments. In the case of antiparallel ?lament velocities, one ?lament is collapsing and fuses with the other ?lament, while the collapsing ?lament exhibits a striated structure. In the case of parallel velocities, both ?laments establish a symmetric con?guration and rotate with constant velocity in the jet. Spatially and temporally resolved features are visualized with a time-colored stroboscopic image.
关键词： plasma materials processing,plasma stability,Image processing
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Strong voltage-boost effect in two-step photon-up conversion solar cells
摘要： Single-image super resolution is a process of obtaining a high-resolution image from a set of low-resolution observations by signal processing. While super resolution has been demonstrated to improve image quality in scaled down images in the image domain, its effects on the Fourier-based image acquisition technique, such as MRI, remains unknown. We performed high-resolution ex vivo late gadolinium enhancement (LGE) magnetic resonance imaging (0.4 × 0.4 × 0.4 mm3) in postinfarction swine hearts (n = 24). The swine hearts were divided into the training set (n = 14) and the test set (n = 10), and in all hearts, low-resolution images were simulated from the high-resolution images. In the training set, super-resolution dictionaries with pairs of small matching patches of the high- and low-resolution images were created. In the test set, super resolution recovered high-resolution images from low-resolution images using the dictionaries. The same algorithm was also applied to patient LGE (n = 4) to assess its effects. Compared with interpolated images, super resolution significantly improved basic image quality indices (P < 0.001). Super resolution using Fourier-based zero padding achieved the best image quality. However, the magnitude of improvement was small in images with zero padding. Super resolution substantially improved the spatial resolution of the patient LGE images by sharpening the edges of the heart and the scar. In conclusion, single-image super resolution significantly improves image errors. However, the magnitude of improvement was relatively small in images with Fourier-based zero padding. These findings provide evidence to support its potential use in myocardial scar imaging.
关键词： magnetic resonance imaging,Image processing,image quality,myocardial scar
更新于2025-09-19 17:13:59
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[IEEE 2019 European Space Power Conference (ESPC) - Juan-les-Pins, France (2019.9.30-2019.10.4)] 2019 European Space Power Conference (ESPC) - III-V on Si solar cells behavior at NIRT and LILT conditions for space applications
摘要： Low-dose CT (LDCT) images tend to be degraded by excessive mottle noise and steak artifacts. In this paper, we proposed a novel fractional-order differentiation model that can be applied to LDCT image processing as a post-processing technique. The anisotropic diffusion model (proposed by Perona and Malik, i.e., PM model) has good performance in ?at regions, total variation (TV) model works better in edge preservation, and fractional-order differentiation models can mitigate block effect while preserving ?ne details and more structure. The proposed model is based on the weighted combinations of the fractional-order PM model and the fractional-order TV model, which maintains the advantages of PM model, TV model, and fractional-order differentiation models. Moreover, the local intensity variance was added to both weighted coef?cient and diffusion coef?cient of the proposed model to properly preserve edges and details. A variety of simulated phantom data, including the Shepp–Logan head phantom, the pelvis phantom, and the actual thoracic phantom, were used for experimental validation. The results of numerical simulation and clinical data experiments demonstrate that the proposed approach has a better performance in both noise suppression and detail preservation, when compared with several other existing methods.
关键词： edge and detail preservation,fractional-order differentiation model,Low-dose CT,image processing
更新于2025-09-19 17:13:59