X-ray dark-field imaging using a grating interferometer has shown potential benefits for a variety of applications in recent years.X-ray dark-field image is commonly retrieved by using discrete Fourier transform from ...X-ray dark-field imaging using a grating interferometer has shown potential benefits for a variety of applications in recent years.X-ray dark-field image is commonly retrieved by using discrete Fourier transform from the acquired phasestepping data.The retrieval process assumes a constant phase step size and a constant flux for each stepped grating position.However,stepping errors and flux fluctuations inevitably occur due to external vibrations and/or thermal drift during data acquisition.Previous studies have shown that those influences introduce errors in the acquired phase-stepping data,which cause obvious moiréartifacts in the retrieved refraction image.This work investigates moiréartifacts in x-ray dark-field imaging as a result of flux fluctuations.For the retrieved mean intensity,amplitude,visibility and dark-field images,the dependence of moiréartifacts on flux fluctuation factors is theoretically derived respectively by using a first-order Taylor series expansion.Results of synchrotron radiation experiments verify the validity of the derived analytical formulas.The spatial frequency characteristics of moiréartifacts are analyzed and compared to those induced by phase-stepping errors.It illustrates that moiréartifacts can be estimated by a weighted mean of flux fluctuation factors,with the weighting factors dependent on the moiréphase and different greatly for each retrieved image.Furthermore,moiréartifacts can even be affected by object’s features not displayed in the particular contrast.These results can be used to interpret images correctly,identify sources of moiréartifacts,and develop dedicated algorithms to remove moiréartifacts in the retrieved multi-contrast images.展开更多
Confucius was born in the state of Lu,the cultural exemplar of ritual propriety and music during the Zhou Dynasty period.Immersed in this rich cultural environment,the young Confucius enjoyed laying out cups and bowls...Confucius was born in the state of Lu,the cultural exemplar of ritual propriety and music during the Zhou Dynasty period.Immersed in this rich cultural environment,the young Confucius enjoyed laying out cups and bowls fashioned from clay on a table,pretending to officiate at mock rituals.Confucius’early life laid the groundwork for his future development as a master of ritual propriety and music and the founder of the influential Confucian school.展开更多
This study aims to clarify the conceptual characteristics of artifact utilization in nursing practice instruction. Five selected articles were analyzed using the concept analysis method by Walker and Avant. The attrib...This study aims to clarify the conceptual characteristics of artifact utilization in nursing practice instruction. Five selected articles were analyzed using the concept analysis method by Walker and Avant. The attributes, antecedents, and consequences of the concept were extracted from the target literature. The analysis revealed two attributes (“connecting people to people” and “connecting people to objects”);two antecedents (“recognition of artifacts” and “selection of artifacts”);and two consequences (“designing a fulfilling learning environment” and “improving the quality of education”). The concept was defined as “promoting the utilization of artifacts by recognizing and selecting them, connecting people to people and people to objects, designing a fulfilling learning environment, and improving the quality of education”.展开更多
A review of previous archaeological studies on the Xia,Shang,and Zhou dynasties reveals that the classification of artifacts has largely relied on researchers’subjective judgments.This phenomenon is limited by both o...A review of previous archaeological studies on the Xia,Shang,and Zhou dynasties reveals that the classification of artifacts has largely relied on researchers’subjective judgments.This phenomenon is limited by both objective conditions and the researchers’subjective understanding.By analyzing bronzes excavated from a Warring States tomb at Majia town,Xindu district,Chengdu,located in southwestern China’s Sichuan province,this study attempts to develop a more objective methodological framework through three steps:(a)identifying representative examples with well-preserved artifacts and primary contexts;(b)establishing classification criteria based on artifact forms,quantities,spatial arrangements,and anomalies;and(c)testing these criteria against a broader range of archaeological materials.展开更多
BACKGROUND Posterior lumbar interbody fusion has good clinical results,but adjacent segment disease(ASD)affects its long-term efficacy.In patients with L4-5 fusion who were followed up for more than 10 years,the ASD i...BACKGROUND Posterior lumbar interbody fusion has good clinical results,but adjacent segment disease(ASD)affects its long-term efficacy.In patients with L4-5 fusion who were followed up for more than 10 years,the ASD incidence was 33.3%.Magnetic resonance imaging(MRI)is key for ASD diagnosis,but metal artifacts from internal fixation limit its use;therefore,removing the artifacts is crucial for ASD diagnosis and treatment.AIM To evaluate the value of WARP MRI for patients with lumbar ASD.METHODS In our hospital,the lumbar spines of patients with ASD were assessed via lumbar MRI,including conventional sequences and sequences for artifacts.A PACS workstation was used for image measurement,analysis,and assessment,which mainly included measurement of the internal fixation implant artifact area,evaluation of the visibility of the anatomical structures surrounding the implant,and diagnostic assessment of ASD in the section.Conventional MRI data sequences and artifacts to sequence the contrast analysis of the MRI data.RESULTS A total of 30 patients with ASD after lumbar fusion and internal fixation were included in the study;the patients included 13 male and 17 female patients and were aged 66.03±5.83 years.The metal artifact area of the WARP T2-tirm sequence was significantly smaller than that of the conventional STIR sequence[(20.85±6.27)cm²vs(50.56±8.55)cm²,P<0.01].The WARP T2-tirm sequence was observed around the implants,pedicles,intervertebral foramen,and vertebral bodies,and the conventional STIR sequence clearly displayed nerve roots within the intervertebral foramen.In all 30 patients,all adjacent segments of the WARP T2-tirm sequence could be clearly observed(above Grade 4),whereas it was difficult to observe these segments in the conventional STIR sequence due to the presence of more severe metal artifacts.CONCLUSION WARP sequences can significantly reduce the artifact area in the sagittal and cross-sectional images of titanium alloy spinal fixation,providing a good imaging reference for the diagnosis of ASD.展开更多
Cultural artifacts exhibitions are among the most profound and appealing forms of cultural exchange.These exhibitions serve as an important bridge for fostering friendly relations between countries and bringing people...Cultural artifacts exhibitions are among the most profound and appealing forms of cultural exchange.These exhibitions serve as an important bridge for fostering friendly relations between countries and bringing people closer together.展开更多
The translation of ancient Chinese cultural artifacts terminology in museums plays a pivotal role in facilitating cross-cultural communication and preserving cultural heritage in the context of globalization.Through f...The translation of ancient Chinese cultural artifacts terminology in museums plays a pivotal role in facilitating cross-cultural communication and preserving cultural heritage in the context of globalization.Through field research in over ten Chinese museums and analysis of more than 800 terms,this paper explores the most effective translation methods for such terminology,focusing on transliteration and literal translation under the strategy of foreignization as well as liberal translation and imitation under the domesticating strategy.Standardized terminology not only prevents ambiguities but also bridges cultural gaps by preserving phonetic authenticity while contextualizing functionality.By refining translation practices,museums can better fulfill their mission as bridges between cultures,promoting global appreciation of China’s rich historical and artistic legacy.展开更多
In situ X-ray diffraction(XRD)has been widely employed to probe the structural evolution of lithium-ion battery electrodes.However,electrodes with practically relevant high-energy densities often exhibit pronounced el...In situ X-ray diffraction(XRD)has been widely employed to probe the structural evolution of lithium-ion battery electrodes.However,electrodes with practically relevant high-energy densities often exhibit pronounced electrochemical inhomogeneities,which substantially hinder accurate structu ral interpretatio n.In this study,we systematically investigate the origin and characteristics of localized electrochemical dead zones(LEDZs)observed during in situ XRD measurements.Through comprehensive analyses using modified coin cells and pouch cells containing various cathode materials under diverse electrochemical conditions,we identify insufficient electron and ion conductivity as the prima ry cause of LEDZ formation.Crucially,our results demonstrate that decoupling electron and ion transport pathways from the X-ray beam direction-an effect inherently realized in pouch cell configurations-effectively mitigates LEDZs,thereby enabling artifact-free structural analysis.This work underscores the critical role of cell geometry and conductivity pathways in achieving accurate structural characterization,providing fundamental guidelines for the design and interpretation of high-energy-density lithium-ion battery electrodes.展开更多
The pain-evoked potential electroencephalogram(EEG)is an effective electrophysiological indicator for pain assessment,yet its extraction is challenging due to interference from background activity and involuntary blin...The pain-evoked potential electroencephalogram(EEG)is an effective electrophysiological indicator for pain assessment,yet its extraction is challenging due to interference from background activity and involuntary blinks.Although existing blink artifact-removal methods show efficacy,they face limitations such as the need for reference signals,neglect of individual differences,and reliance on user input,hindering their practical application in clinical pain assessments.In this paper,we propose a novel framework applying adaptive quadrature mirror filter banks(AQMFB)with discrete wavelet transform(DWT)to remove blink artifacts in pain EEG.Unlike traditional DWT methods that apply fixed wavelets across subjects,our method adapts wavelet construction based on the characteristics of EEG.Experimental results demonstrate that AQMFB-DWT outperforms four leading methods in removing blink artifacts with minimal distortion of pain information,all within an acceptable processing time.This technique is a valuable preprocessing step for enhancing the extraction of pain-evoked potentials.展开更多
Moirésuperlattices hosting flat bands and correlated states have become a central focus in condensed matter research.Using first-principles calculations,we investigate three-dimensional flat bands in alternating ...Moirésuperlattices hosting flat bands and correlated states have become a central focus in condensed matter research.Using first-principles calculations,we investigate three-dimensional flat bands in alternating twisted NbSe_(2)moirébulk structures,which exhibit stronger interlayer interactions than twisted bilayer configurations.Our results show that moirébulks undergo spontaneous large-scale structural relaxation,leading to the formation of remarkably flat energy bands at twist angles≤7.31°.The k_(z)-dependent dispersion of these flat bands across different moirébulks highlights their intrinsic three-dimensional character.Moreover,the presence of out-of-plane mirror symmetry in these moirébulk structures indicates potential interlayer triplet superconducting pairing mechanisms,distinct from those in twisted bilayer systems.This work opens new avenues for exploring three-dimensional flat bands in other moirébulk systems.展开更多
Optical coherence tomography(OCT),particularly Swept-Source OCT,is widely employed in medical diagnostics and industrial inspections owing to its high-resolution imaging capabilities.However,Swept-Source OCT 3D imagin...Optical coherence tomography(OCT),particularly Swept-Source OCT,is widely employed in medical diagnostics and industrial inspections owing to its high-resolution imaging capabilities.However,Swept-Source OCT 3D imaging often suffers from stripe artifacts caused by unstable light sources,system noise,and environmental interference,posing challenges to real-time processing of large-scale datasets.To address this issue,this study introduces a real-time reconstruction system that integrates stripe-artifact suppression and parallel computing using a graphics processing unit.This approach employs a frequency-domain filtering algorithm with adaptive anti-suppression parameters,dynamically adjusted through an image quality evaluation function and optimized using a convolutional neural network for complex frequency-domain feature learning.Additionally,a graphics processing unit integrated 3D reconstruction framework is developed,enhancing data processing throughput and real-time performance via a dual-queue decoupling mechanism.Experimental results demonstrate significant improvements in structural similarity(0.92),peak signal-to-noise ratio(31.62 dB),and stripe suppression ratio(15.73 dB)compared with existing methods.On the RTX 4090 platform,the proposed system achieved an end-to-end delay of 94.36 milliseconds,a frame rate of 10.3 frames per second,and a throughput of 121.5 million voxels per second,effectively suppressing artifacts while preserving image details and enhancing real-time 3D reconstruction performance.展开更多
A simulation method is proposed to predict the motion artifacts of plasma display panels （PDPs）. The method simulates the behavior of the human vision system when perceiving moving objects. The simulation is based o...A simulation method is proposed to predict the motion artifacts of plasma display panels （PDPs）. The method simulates the behavior of the human vision system when perceiving moving objects. The simulation is based on the measured temporal light properties of the display for each gray level and each phosphor. Both the effect of subfield arrangement and phosphor decay are involved. A novel algorithm is proposed to improve the calculation speed. The simulation model manages to predict the appearance of the motion image perceived by a human with a still image. The results are validated by a set of perceptual evaluation experiments. This rapid and accurate prediction of motion artifacts enables objective characterization of the PDP performance in this aspect.展开更多
A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating...A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating seismic discontinuities in the crust and mantle.However,layering arti-fact also exists due to limitations in seismic processing and data coverage.There is a tendency for seis-mic stacking methods to over-map reflectors and scatters into along-isochron layers.In contrast,seis-mic tomography methods tend to under-map sub-horizontal layers with along-raypath smears and ar-tifacts of various de-mean processes.To better identify signals and artifacts in seismic imageries,it is necessary to understand the origins of various artifacts and make careful comparison between the solu-tions of different data and methods.展开更多
This paper proposes a new adaptive post-filtering algorithm to remove coding artifacts in block-based video coder. The proposed method concentrates on blocking and ringing artifacts removal. For de-blocking, the block...This paper proposes a new adaptive post-filtering algorithm to remove coding artifacts in block-based video coder. The proposed method concentrates on blocking and ringing artifacts removal. For de-blocking, the blocking strength is identified to determine the filtering range, and the maximum quantization parameter of the image is used to adapt the 1D fuzzy filter. For de-ringing, besides the edge detection, a complementary ringing detection method is proposed to locate the neglected ringing blocks, and the gradient threshold is adopted to adjust the parameter of 2D fuzzy filter. Experiments are performed on the MPEG-4 sequences. Compared with other methods, the proposed one achieves better detail preservation and artifacts removal performance with lower computational cost.展开更多
Interferometric synthetic aperture radar(InSAR)has been widely used to measure ground displacements related to geophysical and anthropic activities over the past three decades.Satellite SAR systems use microwave signa...Interferometric synthetic aperture radar(InSAR)has been widely used to measure ground displacements related to geophysical and anthropic activities over the past three decades.Satellite SAR systems use microwave signals that interact with the ionosphere when they travel through it during the imaging processes.In this context,ionospheric variations can significantly contaminate SAR imagery,which in turn affects spaceborne InSAR measurements.This bias also leads to a decrease in the coherence and accuracy of InSAR measurements,especially for the low-frequency SAR systems.In this paper,we give an overview of the latest methods for mitigating the ionospheric contributions in InSAR,including Faraday rotation method,azimuth shift method,and range split-spectrum method,and only focus on the single pair of InSAR interferograms.The current challenges and future perspectives are outlined at the end of this paper.展开更多
BACKGROUND Endoscopy artifacts are widespread in real capsule endoscopy(CE)images but not in high-quality standard datasets.AIM To improve the segmentation performance of polyps from CE images with artifacts based on ...BACKGROUND Endoscopy artifacts are widespread in real capsule endoscopy(CE)images but not in high-quality standard datasets.AIM To improve the segmentation performance of polyps from CE images with artifacts based on ensemble learning.METHODS We collected 277 polyp images with CE artifacts from 5760 h of videos from 480 patients at Guangzhou First People’s Hospital from January 2016 to December 2019.Two public high-quality standard external datasets were retrieved and used for the comparison experiments.For each dataset,we randomly segmented the data into training,validation,and testing sets for model training,selection,and testing.We compared the performance of the base models and the ensemble model in segmenting polyps from images with artifacts.RESULTS The performance of the semantic segmentation model was affected by artifacts in the sample images,which also affected the results of polyp detection by CE using a single model.The evaluation based on real datasets with artifacts and standard datasets showed that the ensemble model of all state-of-the-art models performed better than the best corresponding base learner on the real dataset with artifacts.Compared with the corresponding optimal base learners,the intersection over union(IoU)and dice of the ensemble learning model increased to different degrees,ranging from 0.08%to 7.01%and 0.61%to 4.93%,respectively.Moreover,in the standard datasets without artifacts,most of the ensemble models were slightly better than the base learner,as demonstrated by the IoU and dice increases ranging from-0.28%to 1.20%and-0.61%to 0.76%,respectively.CONCLUSION Ensemble learning can improve the segmentation accuracy of polyps from CE images with artifacts.Our results demonstrated an improvement in the detection rate of polyps with interference from artifacts.展开更多
Cone-beam CT (CBCT) scanners are based on volumetric tomography, using a 2D extended digital array providing an area detector [1,2]. Compared to traditional CT, CBCT has many advantages, such as less X-ray beam limita...Cone-beam CT (CBCT) scanners are based on volumetric tomography, using a 2D extended digital array providing an area detector [1,2]. Compared to traditional CT, CBCT has many advantages, such as less X-ray beam limitation, and rapid scan time, etc. However, in CBCT images the x-ray beam has lower mean kilovolt (peak) energy, so the metal artifact is more pronounced on. The position of the shadowed region in other views can be tracked by projecting the 3D coordinates of the object. Automatic image segmentation was used to replace the pixels inside the metal object with the boundary pixels. The modified projection data, using synthetically Radon Transformation, were then used to reconstruct a new back projected CBCT image. In this paper, we present a method, based on the morphological, area and pixel operators, which we applied on the Radon transformed image, to reduce the metal artifacts in CBCT, then we built the Radon back project images using the radon invers transformation. The artifacts effects on the 3d-reconstruction is that, the soft tissues appears as bones or teeth. For the preprocessing of the CBCT images, two methods are used to recognize the noisy black areas that the first depends on thresholding and closing algorithm, and the second depends on tracing boundaries after using thresholding algorithm too. The intensity of these areas is the lowest in the image than other tissues, so we profit this property to detect the edges of these areas. These two methods are applied on phantom and patient image data. It deals with reconstructed CBCT dicom images and can effectively reduce such metal artifacts. Due to the data of the constructed images are corrupted by these metal artifacts, qualitative and quantitative analysis of CBCT images is very essential.展开更多
This review paper aims to summarize cardiac CT blooming artifacts,how they present clinically and what their root causes and potential solutions are.A literature survey was performed covering any publications with a s...This review paper aims to summarize cardiac CT blooming artifacts,how they present clinically and what their root causes and potential solutions are.A literature survey was performed covering any publications with a specific interest in calcium blooming and stent blooming in cardiac CT.The claims from literature are compared and interpreted,aiming at narrowing down the root causes and most promising solutions for blooming artifacts.More than 30 journal publications were identified with specific relevance to blooming artifacts.The main reported causes of blooming artifacts are the partial volume effect,motion artifacts and beam hardening.The proposed solutions are classified as high-resolution CT hardware,high-resolution CT reconstruction,subtraction techniques and post-processing techniques,with a special emphasis on deep learning(DL)techniques.The partial volume effect is the leading cause of blooming artifacts.The partial volume effect can be minimized by increasing the CT spatial resolution through higherresolution CT hardware or advanced high-resolution CT reconstruction.In addition,DL techniques have shown great promise to correct for blooming artifacts.A combination of these techniques could avoid repeat scans for subtraction techniques.展开更多
Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues...Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues are complicated,thus result in severe artifacts.In this study,to reveal the underlying mechanisms of artifacts,we deeply investigate the distribution of specific absorption rate(SAR)inside tissue-mimicking phantoms with varied morphological features using both mathematical simulations and corresponding experiments.Our simulated results,which are confirmed by the associated experimental results,show that the SAR distri-bution highly depends on the geometries of the imaging targets and the polarizing features of the microwave.In addition,we propose the potential mechanisms including Mie-scattering,Fabry-Perot-feature,small curvature effect to interpret the diffraction effect in different scenarios,which may provide basic guidance to predict and distinguish the artifacts for TAI in both fundamental and clinical studies.展开更多
Removing different types of artifacts from the electroencephalography(EEG)recordings is a critical step in performing EEG signal analysis and diagnosis.Most of the existing algorithms aim for removing single type of a...Removing different types of artifacts from the electroencephalography(EEG)recordings is a critical step in performing EEG signal analysis and diagnosis.Most of the existing algorithms aim for removing single type of artifacts,leading to a complex system if an EEG recording contains different types of artifacts.With the advancement in wearable technologies,it is necessary to develop an energy-efficient algorithm to deal with different types of artifacts for single-channel wearable EEG devices.In this paper,an automatic EEG artifact removal algorithm is proposed that effectively reduces three types of artifacts,i.e.,ocular artifact(OA),transmission-line/harmonic-wave artifact(TA/HA),and muscle artifact(MA),from a single-channel EEG recording.The effectiveness of the proposed algorithm is verified on both simulated noisy EEG signals and real EEG from CHB-MIT dataset.The experimental results show that the proposed algorithm effectively suppresses OA,MA and TA/HA from a single-channel EEG recording as well as physical movement artifact.展开更多
基金the Natural Science Foundation of China(Grant Nos.U1532113,11475170,and 11905041)Fundamental Research Funds for the Central Universities(Grant No.PA2020GDKC0024)Anhui Provincial Natural Science Foundation(Grant No.2208085MA18).
文摘X-ray dark-field imaging using a grating interferometer has shown potential benefits for a variety of applications in recent years.X-ray dark-field image is commonly retrieved by using discrete Fourier transform from the acquired phasestepping data.The retrieval process assumes a constant phase step size and a constant flux for each stepped grating position.However,stepping errors and flux fluctuations inevitably occur due to external vibrations and/or thermal drift during data acquisition.Previous studies have shown that those influences introduce errors in the acquired phase-stepping data,which cause obvious moiréartifacts in the retrieved refraction image.This work investigates moiréartifacts in x-ray dark-field imaging as a result of flux fluctuations.For the retrieved mean intensity,amplitude,visibility and dark-field images,the dependence of moiréartifacts on flux fluctuation factors is theoretically derived respectively by using a first-order Taylor series expansion.Results of synchrotron radiation experiments verify the validity of the derived analytical formulas.The spatial frequency characteristics of moiréartifacts are analyzed and compared to those induced by phase-stepping errors.It illustrates that moiréartifacts can be estimated by a weighted mean of flux fluctuation factors,with the weighting factors dependent on the moiréphase and different greatly for each retrieved image.Furthermore,moiréartifacts can even be affected by object’s features not displayed in the particular contrast.These results can be used to interpret images correctly,identify sources of moiréartifacts,and develop dedicated algorithms to remove moiréartifacts in the retrieved multi-contrast images.
文摘Confucius was born in the state of Lu,the cultural exemplar of ritual propriety and music during the Zhou Dynasty period.Immersed in this rich cultural environment,the young Confucius enjoyed laying out cups and bowls fashioned from clay on a table,pretending to officiate at mock rituals.Confucius’early life laid the groundwork for his future development as a master of ritual propriety and music and the founder of the influential Confucian school.
文摘This study aims to clarify the conceptual characteristics of artifact utilization in nursing practice instruction. Five selected articles were analyzed using the concept analysis method by Walker and Avant. The attributes, antecedents, and consequences of the concept were extracted from the target literature. The analysis revealed two attributes (“connecting people to people” and “connecting people to objects”);two antecedents (“recognition of artifacts” and “selection of artifacts”);and two consequences (“designing a fulfilling learning environment” and “improving the quality of education”). The concept was defined as “promoting the utilization of artifacts by recognizing and selecting them, connecting people to people and people to objects, designing a fulfilling learning environment, and improving the quality of education”.
基金the National Social Science Fund of China-sponsored key project Collation and Research of Materials from the Sanxingdui Sacrificial Pit(Grant No.:22AKG006).
文摘A review of previous archaeological studies on the Xia,Shang,and Zhou dynasties reveals that the classification of artifacts has largely relied on researchers’subjective judgments.This phenomenon is limited by both objective conditions and the researchers’subjective understanding.By analyzing bronzes excavated from a Warring States tomb at Majia town,Xindu district,Chengdu,located in southwestern China’s Sichuan province,this study attempts to develop a more objective methodological framework through three steps:(a)identifying representative examples with well-preserved artifacts and primary contexts;(b)establishing classification criteria based on artifact forms,quantities,spatial arrangements,and anomalies;and(c)testing these criteria against a broader range of archaeological materials.
基金Supported by Shanghai Tongren Hospital Scientific Research Funds,No.TRKYRC-xx202203Shanghai Municipal Health Commission,No.2022YQ006Science and Technology Commission of Shanghai Municipality,No.22ZR1457200.
文摘BACKGROUND Posterior lumbar interbody fusion has good clinical results,but adjacent segment disease(ASD)affects its long-term efficacy.In patients with L4-5 fusion who were followed up for more than 10 years,the ASD incidence was 33.3%.Magnetic resonance imaging(MRI)is key for ASD diagnosis,but metal artifacts from internal fixation limit its use;therefore,removing the artifacts is crucial for ASD diagnosis and treatment.AIM To evaluate the value of WARP MRI for patients with lumbar ASD.METHODS In our hospital,the lumbar spines of patients with ASD were assessed via lumbar MRI,including conventional sequences and sequences for artifacts.A PACS workstation was used for image measurement,analysis,and assessment,which mainly included measurement of the internal fixation implant artifact area,evaluation of the visibility of the anatomical structures surrounding the implant,and diagnostic assessment of ASD in the section.Conventional MRI data sequences and artifacts to sequence the contrast analysis of the MRI data.RESULTS A total of 30 patients with ASD after lumbar fusion and internal fixation were included in the study;the patients included 13 male and 17 female patients and were aged 66.03±5.83 years.The metal artifact area of the WARP T2-tirm sequence was significantly smaller than that of the conventional STIR sequence[(20.85±6.27)cm²vs(50.56±8.55)cm²,P<0.01].The WARP T2-tirm sequence was observed around the implants,pedicles,intervertebral foramen,and vertebral bodies,and the conventional STIR sequence clearly displayed nerve roots within the intervertebral foramen.In all 30 patients,all adjacent segments of the WARP T2-tirm sequence could be clearly observed(above Grade 4),whereas it was difficult to observe these segments in the conventional STIR sequence due to the presence of more severe metal artifacts.CONCLUSION WARP sequences can significantly reduce the artifact area in the sagittal and cross-sectional images of titanium alloy spinal fixation,providing a good imaging reference for the diagnosis of ASD.
文摘Cultural artifacts exhibitions are among the most profound and appealing forms of cultural exchange.These exhibitions serve as an important bridge for fostering friendly relations between countries and bringing people closer together.
文摘The translation of ancient Chinese cultural artifacts terminology in museums plays a pivotal role in facilitating cross-cultural communication and preserving cultural heritage in the context of globalization.Through field research in over ten Chinese museums and analysis of more than 800 terms,this paper explores the most effective translation methods for such terminology,focusing on transliteration and literal translation under the strategy of foreignization as well as liberal translation and imitation under the domesticating strategy.Standardized terminology not only prevents ambiguities but also bridges cultural gaps by preserving phonetic authenticity while contextualizing functionality.By refining translation practices,museums can better fulfill their mission as bridges between cultures,promoting global appreciation of China’s rich historical and artistic legacy.
基金supported by the National Research Foundation of Korea(NRF-2022R1C1C1004171,RS-2024-00345331,and RS2024-00413975)supported by the 2025 Research Fund(1.250008.01)of UNIST。
文摘In situ X-ray diffraction(XRD)has been widely employed to probe the structural evolution of lithium-ion battery electrodes.However,electrodes with practically relevant high-energy densities often exhibit pronounced electrochemical inhomogeneities,which substantially hinder accurate structu ral interpretatio n.In this study,we systematically investigate the origin and characteristics of localized electrochemical dead zones(LEDZs)observed during in situ XRD measurements.Through comprehensive analyses using modified coin cells and pouch cells containing various cathode materials under diverse electrochemical conditions,we identify insufficient electron and ion conductivity as the prima ry cause of LEDZ formation.Crucially,our results demonstrate that decoupling electron and ion transport pathways from the X-ray beam direction-an effect inherently realized in pouch cell configurations-effectively mitigates LEDZs,thereby enabling artifact-free structural analysis.This work underscores the critical role of cell geometry and conductivity pathways in achieving accurate structural characterization,providing fundamental guidelines for the design and interpretation of high-energy-density lithium-ion battery electrodes.
文摘The pain-evoked potential electroencephalogram(EEG)is an effective electrophysiological indicator for pain assessment,yet its extraction is challenging due to interference from background activity and involuntary blinks.Although existing blink artifact-removal methods show efficacy,they face limitations such as the need for reference signals,neglect of individual differences,and reliance on user input,hindering their practical application in clinical pain assessments.In this paper,we propose a novel framework applying adaptive quadrature mirror filter banks(AQMFB)with discrete wavelet transform(DWT)to remove blink artifacts in pain EEG.Unlike traditional DWT methods that apply fixed wavelets across subjects,our method adapts wavelet construction based on the characteristics of EEG.Experimental results demonstrate that AQMFB-DWT outperforms four leading methods in removing blink artifacts with minimal distortion of pain information,all within an acceptable processing time.This technique is a valuable preprocessing step for enhancing the extraction of pain-evoked potentials.
基金supported by the National Key Research and Development Program of China(Grant No.2024YFA1410300)the National Natural Science Foundation of China(Grant No.12304217)+1 种基金the Natural Science Foundation of Hunan Province(Grant No.2025JJ60002)the Fundamental Research Funds for the Central Universities of China(Grant No.531119200247)。
文摘Moirésuperlattices hosting flat bands and correlated states have become a central focus in condensed matter research.Using first-principles calculations,we investigate three-dimensional flat bands in alternating twisted NbSe_(2)moirébulk structures,which exhibit stronger interlayer interactions than twisted bilayer configurations.Our results show that moirébulks undergo spontaneous large-scale structural relaxation,leading to the formation of remarkably flat energy bands at twist angles≤7.31°.The k_(z)-dependent dispersion of these flat bands across different moirébulks highlights their intrinsic three-dimensional character.Moreover,the presence of out-of-plane mirror symmetry in these moirébulk structures indicates potential interlayer triplet superconducting pairing mechanisms,distinct from those in twisted bilayer systems.This work opens new avenues for exploring three-dimensional flat bands in other moirébulk systems.
文摘Optical coherence tomography(OCT),particularly Swept-Source OCT,is widely employed in medical diagnostics and industrial inspections owing to its high-resolution imaging capabilities.However,Swept-Source OCT 3D imaging often suffers from stripe artifacts caused by unstable light sources,system noise,and environmental interference,posing challenges to real-time processing of large-scale datasets.To address this issue,this study introduces a real-time reconstruction system that integrates stripe-artifact suppression and parallel computing using a graphics processing unit.This approach employs a frequency-domain filtering algorithm with adaptive anti-suppression parameters,dynamically adjusted through an image quality evaluation function and optimized using a convolutional neural network for complex frequency-domain feature learning.Additionally,a graphics processing unit integrated 3D reconstruction framework is developed,enhancing data processing throughput and real-time performance via a dual-queue decoupling mechanism.Experimental results demonstrate significant improvements in structural similarity(0.92),peak signal-to-noise ratio(31.62 dB),and stripe suppression ratio(15.73 dB)compared with existing methods.On the RTX 4090 platform,the proposed system achieved an end-to-end delay of 94.36 milliseconds,a frame rate of 10.3 frames per second,and a throughput of 121.5 million voxels per second,effectively suppressing artifacts while preserving image details and enhancing real-time 3D reconstruction performance.
文摘A simulation method is proposed to predict the motion artifacts of plasma display panels （PDPs）. The method simulates the behavior of the human vision system when perceiving moving objects. The simulation is based on the measured temporal light properties of the display for each gray level and each phosphor. Both the effect of subfield arrangement and phosphor decay are involved. A novel algorithm is proposed to improve the calculation speed. The simulation model manages to predict the appearance of the motion image perceived by a human with a still image. The results are validated by a set of perceptual evaluation experiments. This rapid and accurate prediction of motion artifacts enables objective characterization of the PDP performance in this aspect.
基金supported by the National Natural Science Foundation of China (No. 40730317)
文摘A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating seismic discontinuities in the crust and mantle.However,layering arti-fact also exists due to limitations in seismic processing and data coverage.There is a tendency for seis-mic stacking methods to over-map reflectors and scatters into along-isochron layers.In contrast,seis-mic tomography methods tend to under-map sub-horizontal layers with along-raypath smears and ar-tifacts of various de-mean processes.To better identify signals and artifacts in seismic imageries,it is necessary to understand the origins of various artifacts and make careful comparison between the solu-tions of different data and methods.
文摘This paper proposes a new adaptive post-filtering algorithm to remove coding artifacts in block-based video coder. The proposed method concentrates on blocking and ringing artifacts removal. For de-blocking, the blocking strength is identified to determine the filtering range, and the maximum quantization parameter of the image is used to adapt the 1D fuzzy filter. For de-ringing, besides the edge detection, a complementary ringing detection method is proposed to locate the neglected ringing blocks, and the gradient threshold is adopted to adjust the parameter of 2D fuzzy filter. Experiments are performed on the MPEG-4 sequences. Compared with other methods, the proposed one achieves better detail preservation and artifacts removal performance with lower computational cost.
基金This work was supported by the National Key Research and Development Program of China(2020YFC1512001)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515011427)+6 种基金the Research Grants Council of the Hong Kong Special Administrative Region(Projects PolyU 152232/17E,PolyU 152164/18Eand PolyU152233/19E)the National NaturalScience Foundation of China(Grants 41790445,41974006,42074040 and 41941019)the Shenzhen Scientific Research and Development Funding Program(Nos.20200807110745001,KQJSCX20180328093453763and20200812164904001)the Department of Education of Guangdong(218KTSCX196)the Fundamental Research Funds for the Central Universities(300102269207)the Research Institute for Sustainable Urban Development(RISUD)(BBWB)the Innovation and Technology Fund of Hong Kong(ITP/019/20LP).
文摘Interferometric synthetic aperture radar(InSAR)has been widely used to measure ground displacements related to geophysical and anthropic activities over the past three decades.Satellite SAR systems use microwave signals that interact with the ionosphere when they travel through it during the imaging processes.In this context,ionospheric variations can significantly contaminate SAR imagery,which in turn affects spaceborne InSAR measurements.This bias also leads to a decrease in the coherence and accuracy of InSAR measurements,especially for the low-frequency SAR systems.In this paper,we give an overview of the latest methods for mitigating the ionospheric contributions in InSAR,including Faraday rotation method,azimuth shift method,and range split-spectrum method,and only focus on the single pair of InSAR interferograms.The current challenges and future perspectives are outlined at the end of this paper.
文摘BACKGROUND Endoscopy artifacts are widespread in real capsule endoscopy(CE)images but not in high-quality standard datasets.AIM To improve the segmentation performance of polyps from CE images with artifacts based on ensemble learning.METHODS We collected 277 polyp images with CE artifacts from 5760 h of videos from 480 patients at Guangzhou First People’s Hospital from January 2016 to December 2019.Two public high-quality standard external datasets were retrieved and used for the comparison experiments.For each dataset,we randomly segmented the data into training,validation,and testing sets for model training,selection,and testing.We compared the performance of the base models and the ensemble model in segmenting polyps from images with artifacts.RESULTS The performance of the semantic segmentation model was affected by artifacts in the sample images,which also affected the results of polyp detection by CE using a single model.The evaluation based on real datasets with artifacts and standard datasets showed that the ensemble model of all state-of-the-art models performed better than the best corresponding base learner on the real dataset with artifacts.Compared with the corresponding optimal base learners,the intersection over union(IoU)and dice of the ensemble learning model increased to different degrees,ranging from 0.08%to 7.01%and 0.61%to 4.93%,respectively.Moreover,in the standard datasets without artifacts,most of the ensemble models were slightly better than the base learner,as demonstrated by the IoU and dice increases ranging from-0.28%to 1.20%and-0.61%to 0.76%,respectively.CONCLUSION Ensemble learning can improve the segmentation accuracy of polyps from CE images with artifacts.Our results demonstrated an improvement in the detection rate of polyps with interference from artifacts.
文摘Cone-beam CT (CBCT) scanners are based on volumetric tomography, using a 2D extended digital array providing an area detector [1,2]. Compared to traditional CT, CBCT has many advantages, such as less X-ray beam limitation, and rapid scan time, etc. However, in CBCT images the x-ray beam has lower mean kilovolt (peak) energy, so the metal artifact is more pronounced on. The position of the shadowed region in other views can be tracked by projecting the 3D coordinates of the object. Automatic image segmentation was used to replace the pixels inside the metal object with the boundary pixels. The modified projection data, using synthetically Radon Transformation, were then used to reconstruct a new back projected CBCT image. In this paper, we present a method, based on the morphological, area and pixel operators, which we applied on the Radon transformed image, to reduce the metal artifacts in CBCT, then we built the Radon back project images using the radon invers transformation. The artifacts effects on the 3d-reconstruction is that, the soft tissues appears as bones or teeth. For the preprocessing of the CBCT images, two methods are used to recognize the noisy black areas that the first depends on thresholding and closing algorithm, and the second depends on tracing boundaries after using thresholding algorithm too. The intensity of these areas is the lowest in the image than other tissues, so we profit this property to detect the edges of these areas. These two methods are applied on phantom and patient image data. It deals with reconstructed CBCT dicom images and can effectively reduce such metal artifacts. Due to the data of the constructed images are corrupted by these metal artifacts, qualitative and quantitative analysis of CBCT images is very essential.
基金Research reported in this publication was supported by the National Heart,Lung,And Blood Institute of the National Institutes of Health,No.R01HL151561The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
文摘This review paper aims to summarize cardiac CT blooming artifacts,how they present clinically and what their root causes and potential solutions are.A literature survey was performed covering any publications with a specific interest in calcium blooming and stent blooming in cardiac CT.The claims from literature are compared and interpreted,aiming at narrowing down the root causes and most promising solutions for blooming artifacts.More than 30 journal publications were identified with specific relevance to blooming artifacts.The main reported causes of blooming artifacts are the partial volume effect,motion artifacts and beam hardening.The proposed solutions are classified as high-resolution CT hardware,high-resolution CT reconstruction,subtraction techniques and post-processing techniques,with a special emphasis on deep learning(DL)techniques.The partial volume effect is the leading cause of blooming artifacts.The partial volume effect can be minimized by increasing the CT spatial resolution through higherresolution CT hardware or advanced high-resolution CT reconstruction.In addition,DL techniques have shown great promise to correct for blooming artifacts.A combination of these techniques could avoid repeat scans for subtraction techniques.
基金This study was supported by the National Natural Science Foundation of China(Nos.62022037,61775028,81571722,61528401 and 61921002)Guangdong province(2019ZT08Y191)+1 种基金Shenzhen Science and Technology Program(KQTD20190929172743294)Startup grant from Southern University of Science and Technology.
文摘Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues are complicated,thus result in severe artifacts.In this study,to reveal the underlying mechanisms of artifacts,we deeply investigate the distribution of specific absorption rate(SAR)inside tissue-mimicking phantoms with varied morphological features using both mathematical simulations and corresponding experiments.Our simulated results,which are confirmed by the associated experimental results,show that the SAR distri-bution highly depends on the geometries of the imaging targets and the polarizing features of the microwave.In addition,we propose the potential mechanisms including Mie-scattering,Fabry-Perot-feature,small curvature effect to interpret the diffraction effect in different scenarios,which may provide basic guidance to predict and distinguish the artifacts for TAI in both fundamental and clinical studies.
基金the National Natural Science Foundation of China(No.61874171)the Alibaba Innovative Research Program of Alibaba Group。
文摘Removing different types of artifacts from the electroencephalography(EEG)recordings is a critical step in performing EEG signal analysis and diagnosis.Most of the existing algorithms aim for removing single type of artifacts,leading to a complex system if an EEG recording contains different types of artifacts.With the advancement in wearable technologies,it is necessary to develop an energy-efficient algorithm to deal with different types of artifacts for single-channel wearable EEG devices.In this paper,an automatic EEG artifact removal algorithm is proposed that effectively reduces three types of artifacts,i.e.,ocular artifact(OA),transmission-line/harmonic-wave artifact(TA/HA),and muscle artifact(MA),from a single-channel EEG recording.The effectiveness of the proposed algorithm is verified on both simulated noisy EEG signals and real EEG from CHB-MIT dataset.The experimental results show that the proposed algorithm effectively suppresses OA,MA and TA/HA from a single-channel EEG recording as well as physical movement artifact.
