scholarly journals A new denoising strategy and the X-shaped supplement denoising operator targeting time-reversed mirror imaging technique

2021 ◽  
Vol 18 (4) ◽  
pp. 503-514
Author(s):  
Lingli Zhang ◽  
Yuxiao Ren ◽  
Lei Chen ◽  
Kai Wang ◽  
Xinji Xu ◽  
...  
Keyword(s):  
Reference Model ◽  
Imaging Technique ◽  
Velocity Model ◽  
Laplacian Operator ◽  
Imaging Method ◽  
Geometric Features ◽  
Conventional Imaging ◽  
Imaging Methods ◽  
Seismic Wavelet ◽  
Residual Noise

Abstract Imaging of vertical structures is a challenge in the seismic imaging field. The conventional imaging methods for vertical structures are highly dependent on the reference model or boreholes. Time-reversed mirror imaging can effectively image the vertical structures based on the multiples and a smoothed velocity model without the need of accurate seismic wavelet estimation. Although the Laplacian operator is applied in time-reversed mirror imaging, there still exists severe residual noise. In this study, we developed a new imaging denoising strategy and an X-shaped supplement denoising operator for time-reversed mirror imaging based on the geometric features of the image and the causes of imaging noise. Synthetic results for the single- and double-staircase model prove the powerful denoising capacity of the X-shaped supplement denoising operator. In addition, the results of a Marmousi model prove that the X-shaped denoising operator can also effectively suppress the noise when applying time-reversed mirror imaging method to image complex inclined structures. However, the X-shaped denoising operator still contains some limitations, such as non-amplitude-preserving.

Wide-area imaging from OBS multiples

Geophysics ◽  
2009 ◽  
Vol 74 (6) ◽  
pp. Q41-Q47 ◽  
Author(s):  
Ranjan Dash ◽  
George Spence ◽  
Roy Hyndman ◽  
Sergio Grion ◽  
Yi Wang ◽  
...  
Keyword(s):  
Single Channel ◽  
Water Layer ◽  
Velocity Model ◽  
Imaging Method ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Conventional Imaging ◽  
Depth Migration ◽  
Reflection Data ◽  
Obs Data

The subseafloor structure offshore western Canada was imaged using first-order water-layer multiples from ocean-bottom seismometer (OBS) data and the results were compared to conventional imaging using primary reflections. This multiple-migration (mirror-imaging) method uses the downgoing pressure wavefield just above the seafloor, which is devoid of any primary reflections but consists of receiver-side ghosts of these primary reflections. The mirror-imaging method employs a primaries-only Kirchhoff prestack depth migration algorithm to image the receiver ghosts. The additional travel path of the multiples through the water layer is accounted for by a simple manipulation of the velocity model and processing datum: the receivers lie not on the seabed but on a sea surface twice as high as the true water column. Migration results show that the multiple-migrated image provides a much broader illumination of the subsurface than is possible for conventional imaging using the primaries, especially for the very shallow reflections and sparse OBS spacing. The resulting image from mirror imaging has illumination comparable to the vertical incidence surface streamer (single-channel) reflection data.

scholarly journals The financial burden of imaging tests conducted in the emergency department of a teaching hospital: a brief report

2019 ◽  
Vol 6 (1) ◽  
pp. 43-46
Author(s):  
Sahar Mirbaha ◽  
Mohammadmehdi Forouzanfar ◽  
Amin Saberinia ◽  
Amir Salimi ◽  
Hamid Kariman ◽  
...  
Keyword(s):  
Emergency Department ◽  
Ct Scan ◽  
Imaging Technique ◽  
Financial Burden ◽  
Imaging Method ◽  
Total Cost ◽  
Imaging Methods ◽  
Number Of Patients ◽  
Different Types ◽  
One Year

Objective: Each imaging technique has a special application and usage, and should be used in the right situation. Physicians choose the type of imaging technique by considering the type of tissue and the benefits and disadvantages of the imaging method as well as its financial burden on the patient. The aim of this study was to estimate the cost of imaging tests performed in the emergency department (ED) of an educational hospital and determine their financial burden on both the patients and the healthcare system of the country. Methods: This retrospective descriptive cross-sectional single-center study was conducted in Shohadaye Tajrish, an educational hospital, during one year. The study population consisted of all patients who had undergone some type of imaging (CT scan, ultrasound, radiography, magnetic resonance imaging [MRI]) in the ED. The information was collected using a predesigned checklist. The costs of a variety of imaging methods for patients referred to the ED were calculated using different types of accounting units and PACS system. Results: The number of patients who visited the ED of the studied hospital during a one year period was 63507. The total cost of performing different types of imaging methods in the studied center throughout the one-year target period was 44018695695 Rials (≃$US 423745) (59.27% of which was spent on CT scan, 16.09% on ultrasound, 13.75% on plain radiography and 10.87% on MRI). Conclusion: According to the collected data, the total cost of radiology was 44018695695 Rials. The highest cost was related to CT scan modality, and the lowest belonged to MRI.

Measurement Tools for Non-Invasive Monitoring of the Plants Growth Conditions by Using Hyperspectral Imaging Methods: a Review

2021 ◽  
Vol 2 (43) ◽  
pp. 54-61
Author(s):  
Dmitriy A. Burynin ◽  
◽  
Aleksandr A. Smirnov
Keyword(s):  
Hyperspectral Imaging ◽  
Physiological State ◽  
Effective Means ◽  
Research Problem ◽  
High Spectral Resolution ◽  
Research Purpose ◽  
Imaging Method ◽  
Invasive Monitoring ◽  
Imaging Methods ◽  
Non Invasive

Portable spectroradiometers and hyperspectral cameras are increasingly being used to quickly assess the physiological state of plants. The operation of these devices is based on the registration of reflection or reflection and transmission spectra. (Research purpose) The research purpose is in analyzing the technical means and methods of non-invasive monitoring of the plant state based on the registration of the reflection spectra of leaves. (Materials and methods) The article presents a review of the work on the application of hyperspectral imaging methods. Authors classified and analyzed materials on spectroscopic radiometers and hyperspectral cameras, and outlined the prospects for implementation. Authors applied the methods of a systematic approach to the research problem. (Results and discussion) Hyperspectral imaging methods serve as an effective means of monitoring plants. It is possible to determine the pigment composition of plants, lack of nutrition, and detect biotic stress through hyperspectral imaging. The article presents methods of application of portable spectroradiometers and hyperspectral cameras. With the help of these devices it is possible to carry out measurements with high spectral resolution. The difficulty of accurately detecting the content of pigments in the leaves lies in the mutual overlap of the areas of light absorption by them. The main drawback of spectroradiometers is that they measure only at one point on a single sheet. The article presents the difficulties encountered in interpreting the results obtained by the hyperspectral camera. The background reflectivity of the soil, the geometry of the vegetation cover, and the uneven lighting can make errors in the measurements. (Conclusions) The article presents the disadvantages of the hyperspectral imaging method when using only the reflection spectrum. In order to increase the accuracy of the determination of pigments and stresses of various origins, it is necessary to develop a portable device that combines the methods of recording reflection and fluorescence.

Conventional Imaging Methods

2003 ◽  
pp. 55-134
Author(s):  
Marinus T. Vlaardingerbroek ◽  
Jacques A. den Boer
Keyword(s):  
Conventional Imaging ◽  
Imaging Methods

Laplacian-based 3D mesh simplification with feature preservation

2019 ◽  
Vol 10 (02) ◽  
pp. 1950002 ◽  
Author(s):  
Wei Lyu ◽  
Wei Wu ◽  
Lin Zhang ◽  
Zhaohui Wu ◽  
Zhong Zhou
Keyword(s):  
Clustering Algorithm ◽  
Shape Descriptor ◽  
Mesh Simplification ◽  
Feature Weighting ◽  
Laplacian Operator ◽  
Geometric Features ◽  
Error Statistics ◽  
3D Mesh ◽  
Surface Meshes ◽  
Improving Accuracy

We propose a novel Laplacian-based algorithm that simplifies triangle surface meshes and can provide different preservation ratios of geometric features. Our efficient and fast algorithm uses a 3D mesh model as input and initially detects geometric features by using a Laplacian-based shape descriptor (L-descriptor). The algorithm further performs an optimized clustering approach that combines a Laplacian operator with K-means clustering algorithm to perform vertex classification. Moreover, we introduce a Laplacian weighted cost function based on L-descriptor to perform feature weighting and error statistics comparison, which are further used to change the deletion order of the model elements and preserve the saliency features. Our algorithm can provide different preservation ratios of geometric features and may be extended to handle arbitrary mesh topologies. Our experiments on a variety of 3D surface meshes demonstrate the advantages of our algorithm in terms of improving accuracy and applicability, and preserving saliency geometric features.

scholarly journals Recent Progress in X-ray and Neutron Phase Imaging with Gratings

2020 ◽  
Vol 4 (1) ◽  
pp. 9 ◽  
Author(s):  
Atsushi Momose ◽  
Hidekazu Takano ◽  
Yanlin Wu ◽  
Koh Hashimoto ◽  
Tetsuo Samoto ◽  
...  
Keyword(s):  
Recent Progress ◽  
Time Of Flight ◽  
Imaging Method ◽  
Phase Imaging ◽  
Imaging Methods ◽  
X Ray ◽  
Phase Microscopy ◽  
Grating Fabrication ◽  
Recent Developments ◽  
Time Of Flight Method

Under the JST-ERATO project in progress to develop X-ray and neutron phase-imaging methods together, recent achievements have been selected and reviewed after describing the merit and the principle of the phase imaging method. For X-ray phase imaging, recent developments of four-dimensional phase tomography and phase microscopy at SPring-8, Japan are mainly presented. For neutron phase imaging, an approach in combination with the time-of-flight method developed at J-PARC, Japan is described with the description of new Gd grating fabrication.

Novel Approaches to Nanopatterning: From Surface Monolayer Initiated Polymerization to Hybrid Organometallic-Organic Bilayers

2001 ◽  
Vol 705 ◽  
Author(s):  
Clifford L. Henderson ◽  
Sean Barstow ◽  
Augustin Jeyakumar ◽  
Kendra McCoy ◽  
Dennis W. Hess ◽  
...  
Keyword(s):  
Barrier Layer ◽  
Photoelectron Spectroscopy ◽  
Single Layer ◽  
Polymeric Materials ◽  
Polymerization Process ◽  
Precursor Film ◽  
Imaging Method ◽  
Surface Imaging ◽  
Imaging Methods ◽  
Organometallic Precursor

AbstractThe extendability of conventional subtractive lithographic processing using spin-coated polymeric single layer resists (SLR) faces many challenges as feature sizes in microelectronics push below 100 nm. In addition, the opacity of the polymeric materials traditionally used as SLR resins to future exposure sources presents new challenges as the radiation penetration depth decreases (e.g. 157 nm, EUVL, low keV e-beam). One solution to these problems is the use of surface imaging materials and processes. In such surface imaging methods, exposure in only a thin surface layer is used to create a pattern in a substantially thicker etch barrier layer. Conventional surface imaging approaches have mainly focused on silylation techniques which have experienced a variety of problems. This paper presents an update on two novel surface imaging methods under investigation: (1) surface monolayer initiated polymerization (SMIP) and (2) organometallic-organic bilayer resists.The SMIP process involves using a monolayer that contains a polymerization initiator functionality. Exposure of the monolayer to radiation can deactivate the initiators in selected areas and the remaining initiators can subsequently be used to directly grow patterned polymer structures. This process allows complete decoupling of the imaging properties of the monolayer from the etch properties of the polymer etch barrier. In essence, the polymerization process is used to amplify the pattern initially formed in the monolayer. Recent results are presented that demonstrate the use of x-ray photoelectron spectroscopy in conjunction with dose array experiments to analyze the sensitivity of the initiators used for this process.The other novel surface imaging method presented in this work uses organometallic-organic bilayers. In these systems, thin films of radiation sensitive organometallic precursors are used as an imaging layer in conjunction with thick organic etch barrier layers. Upon exposure, the organometallic precursor film is selectively converted to metal oxide. After exposure, the unexposed regions of the film can be developed away. Subsequent dry pattern transfer in an oxygen plasma can be used to transfer the pattern defined in the thin oxide layer through the organic etch barrier layer. Organometallic precursor films with sensitivities on the order of 70 μC/cm2 are demonstrated which result in oxide films that possess an etch selectivity of 100:1 with respect to novolac in oxygen plasmas. 500 nm line-space patterns are demonstrated as a first lithographic imaging proof-of-concept.

Velocity-estimation improvements and migration/demigration using the common-reflection surface with continuing deconvolution in the time domain

Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. S229-S238 ◽  
Author(s):  
Martina Glöckner ◽  
Sergius Dell ◽  
Benjamin Schwarz ◽  
Claudia Vanelle ◽  
Dirk Gajewski
Keyword(s):  
Model Building ◽  
Velocity Model ◽  
Velocity Estimation ◽  
Initial Time ◽  
Model Errors ◽  
Imaging Methods ◽  
Time Migration ◽  
Common Reflection Surface ◽  
The Common ◽  
And Migration

To obtain an image of the earth’s subsurface, time-imaging methods can be applied because they are reasonably fast, are less sensitive to velocity model errors than depth-imaging methods, and are usually easy to parallelize. A powerful tool for time imaging consists of a series of prestack time migrations and demigrations. We have applied multiparameter stacking techniques to obtain an initial time-migration velocity model. The velocity model building proposed here is based on the kinematic wavefield attributes of the common-reflection surface (CRS) method. A subsequent refinement of the velocities uses a coherence filter that is based on a predetermined threshold, followed by an interpolation and smoothing. Then, we perform a migration deconvolution to obtain the final time-migrated image. The migration deconvolution consists of one iteration of least-squares migration with an estimated Hessian. We estimate the Hessian by nonstationary matching filters, i.e., in a data-driven fashion. The model building uses the framework of the CRS, and the migration deconvolution is fully automated. Therefore, minimal user interaction is required to carry out the velocity model refinement and the image update. We apply the velocity refinement and migration deconvolution approaches to complex synthetic and field data.

scholarly journals CIST: An Improved ISAR Imaging Method Using Convolution Neural Network

2020 ◽  
Vol 12 (16) ◽  
pp. 2641
Author(s):  
Shunjun Wei ◽  
Jiadian Liang ◽  
Mou Wang ◽  
Xiangfeng Zeng ◽  
Jun Shi ◽  
...  
Keyword(s):  
Neural Network ◽  
Computational Cost ◽  
Convolution Neural Network ◽  
Imaging Method ◽  
Sampled Data ◽  
High Quality ◽  
Imaging Methods ◽  
Adaptive Parameter ◽  
Imaging Results ◽  
Isar Imaging

Compressive sensing (CS) has been widely utilized in inverse synthetic aperture radar (ISAR) imaging, since ISAR measured data are generally non-completed in cross-range direction, and CS-based imaging methods can obtain high-quality imaging results using under-sampled data. However, the traditional CS-based methods need to pre-define parameters and sparse transforms, which are tough to be hand-crafted. Besides, these methods usually require heavy computational cost with large matrices operation. In this paper, inspired by the adaptive parameter learning and rapidly reconstruction of convolution neural network (CNN), a novel imaging method, called convolution iterative shrinkage-thresholding (CIST) network, is proposed for ISAR efficient sparse imaging. CIST is capable of learning optimal parameters and sparse transforms throughout the CNN training process, instead of being manually defined. Specifically, CIST replaces the linear sparse transform with non-linear convolution operations. This new transform and essential parameters are learnable end-to-end across the iterations, which increases the flexibility and robustness of CIST. When compared with the traditional state-of-the-art CS imaging methods, both simulation and experimental results demonstrate that the proposed CIST-based ISAR imaging method can obtain imaging results of high quality, while maintaining high computational efficiency. CIST-based ISAR imaging is tens of times faster than other methods.

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