A fast, powerful and stable filter based on combined wavelet and Fourier analysis for the elimination of horizontal or vertical stripes in images is presented and compared with other types of destriping filters. Strict separation between artifacts and original features allowing both, suppression of the unwanted structures and high degree of preservation of the original image information is endeavoured. The results are validated by visual assessments, as well as by quantitative estimation of the image energy loss. The capabilities and the performance of the filter are tested on a number of case studies related to applications in tomographic imaging. The case studies include (i) suppression of waterfall artifacts in electron microscopy images based on focussed ion beam nanotomography, (ii) removal of different types of ring artifacts in synchrotron based X-ray microtomography and (iii) suppression of horizontal stripe artifacts from phase projections in grating interferometry. ...
The purpose of this study was to develop, implement and evaluate a dedicated metal artefact reduction (MAR) method for flat-detector CT (FDCT). The algorithm uses the multidimensional raw data space to calculate surrogate attenuation values for the original metal traces in the raw data domain. The metal traces are detected automatically by a three-dimensional, threshold-based segmentation algorithm in an initial reconstructed image volume, based on twofold histogram information for calculating appropriate metal thresholds. These thresholds are combined with constrained morphological operations in the projection domain. A subsequent reconstruction of the modified raw data yields an artefact-reduced image volume that is further processed by a combining procedure that reinserts the missing metal information. For image quality assessment, measurements on semi- anthropomorphic phantoms containing metallic inserts were evaluated in terms of CT value accuracy, image noise and spatial resolution before ...
A circuit and method for compensating for an electrode motion artifact in which the electrode motion artifact is generated because impedance between a subject and a measuring electrode changes during measurement of the subjects biosignal, and the electrode motion artifact can be differentially measured and an electrocardiogram signal can be compensated by introducing a predetermined voltage or an electric current to the subject. A circuit and method for compensating electrode motion artifact, which can differentially measure the difference information between impedance components by introducing a predetermined voltage or electric current to a subject, in association with the electrode motion artifact. In this instance, the impedance component is a component of electrode motion artifact and the electrode motion artifact is generated when measuring a biosignal.
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PURPOSE: To evaluate two commercial CT metal artifact reduction (MAR) algorithms for use in proton treatment planning in the head and neck (H&N) area.. METHODS: An anthropomorphic head phantom with removable metallic implants (dental fillings or neck implant) was CT-scanned to evaluate the O-MAR (Philips) and the iMAR (Siemens) algorithms. Reference images were acquired without any metallic implants in place. Water equivalent thickness (WET) was calculated for different path directions and compared between image sets. Images were also evaluated for use in proton treatment planning for parotid, tonsil, tongue base, and neck node targets. The beams were arranged so as to not traverse any metal prior to the target, enabling evaluation of the impact on dose calculation accuracy from artifacts surrounding the metal volume. Plans were compared based on γ analysis (1 mm distance-to-agreement/1% difference in local dose) and dose volume histogram metrics for targets and organs at risk (OARs). Visual ...
PURPOSE: To evaluate two commercial CT metal artifact reduction (MAR) algorithms for use in proton treatment planning in the head and neck (H&N) area.. METHODS: An anthropomorphic head phantom with removable metallic implants (dental fillings or neck implant) was CT-scanned to evaluate the O-MAR (Philips) and the iMAR (Siemens) algorithms. Reference images were acquired without any metallic implants in place. Water equivalent thickness (WET) was calculated for different path directions and compared between image sets. Images were also evaluated for use in proton treatment planning for parotid, tonsil, tongue base, and neck node targets. The beams were arranged so as to not traverse any metal prior to the target, enabling evaluation of the impact on dose calculation accuracy from artifacts surrounding the metal volume. Plans were compared based on γ analysis (1 mm distance-to-agreement/1% difference in local dose) and dose volume histogram metrics for targets and organs at risk (OARs). Visual ...
TY - JOUR. T1 - Deep learning cross-phase style transfer for motion artifact correction in coronary computed tomography angiography. AU - Jung, Sunghee. AU - Lee, Soochahn. AU - Jeon, Byunghwan. AU - Jang, Yeonggul. AU - Chang, Hyuk Jae. N1 - Funding Information: This work was supported in part by the Institute for Information and Communications Technology Promotion (IITP) (Intelligent SW Technology Development for Medical Data Analysis and Autonomous Digital Companion Framework and Application) under Grant 2018-0-00861 and Grant 2017-0-00255, in part by the National Research Foundation of Korea (NRF) under Grant NRF-2019R1F1A1063656, and in part by the Korean Government (Ministry of Science and ICT (MSIT) and Ministry of Education (MOE)). Publisher Copyright: © 2013 IEEE.. PY - 2020. Y1 - 2020. N2 - Motion artifacts may occur in coronary computed tomography angiography (CCTA) due to the heartbeat and impede the clinicians diagnosis of coronary arterial diseases. Thus, motion artifact ...
Right: Illustration of the twinkling artifact. Shown in A and B are ultrasound images of a 2-mm stone inserted into an in vivo kidney. (A) scan in B-mode only; (B) color Doppler engaged. Note that the twinkling artifact shows a well defined stone (circled) while the B-mode image shows no obvious indication of a stone. (C) a stone is placed near a blood vessel and imaged in vivo; note that it is easy to distinguish between the stone exhibiting the twinkling artifact and regular blood flow. (D) photograph of the stone placed in the kidney ...
Endoscopic artifacts are a core challenge in facilitating the diagnosis and treatment of diseases in hollow organs. Precise detection of specific artifacts like pixel saturations, motion blur, specular reflections, bubbles and debris is essential for high-quality frame restoration and is crucial for realizing reliable computer-assisted tools for improved patient care. At present most videos in endoscopy are currently not analyzed due to the abundant presence of multi-class artifacts in video frames. Through the endoscopic artifact detection (EAD 2019) challenge, we address this key bottleneck problem by solving the accurate identification and localization of endoscopic frame artifacts to enable further key quantitative analysis of unusable video frames such as mosaicking and 3D reconstruction which is crucial for delivering improved patient care. This paper summarizes the challenge tasks and describes the dataset and evaluation criteria established in the EAD 2019 challenge.
acquisition data storage and communication provide for the collection of reliable and useful inhome physiological data Artifacts arising from environmental experimental and physiological factors degrade signal quality and render the affected part of the signal useless The magnitude and frequency of these artifacts significantly increases when data collection is moved from the clinic into the home Signal processing advances have brought about significant improvement in artifact removal over the last number of years This paper reviews the physiological signals most likely to be recorded in the home documenting the artifacts which occur most frequently and which have the largest degrading effect A detailed analysis of current artifact removal techniques will then be presented An evaluation of the advantages and disadvantages of each of the proposed artifact detection and removal techniques with particular application to the personal healthcare domain is provided More Info Published in IEEE ...
The new artifact suppression design is efficient, for instance, in terms of preserving spatial resolution, as it is applied directly to original raw data. It successfully reduced artifacts in CT images of five patients and in phantom images. Sophisticated interpolation methods are needed to obtain r …
ObjectiveThe objective of this study was to assess the accuracy of the quantitative measurements obtained using dual-energy computed tomography with metal artifact reduction software (MARS).MethodsDual-energy computed tomography scans (fast kV-switching) are performed on a phantom, by varying the nu
TY - CHAP. T1 - Reduction of movement artefacts in comparative 3D magnetic resonance (MR) breast imaging. AU - Undrill, Peter Edward. AU - Redpath, Thomas William. AU - Gilbert, Fiona Jane. PY - 1996. Y1 - 1996. KW - image registration. KW - magnetic resonance imaging. KW - breast imaging. KW - principal axes. KW - orthogonal polynomials. KW - pricipal axes. M3 - Chapter. SN - 0-8194-2085-9 VL - 2710. T3 - Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE). SP - 922. EP - 930. BT - Medical Imaging 1996. A2 - Loew, M H. A2 - Hanson, K M ER - ...
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TY - JOUR. T1 - Comparing the Performance of Popular MEG/EEG Artifact Correction Methods in an Evoked-Response Study. AU - Haumann, Niels Trusbak. AU - Parkkonen, Lauri. AU - Kliuchko, Marina. AU - Vuust, Peter. AU - Brattico, Elvira. PY - 2016. Y1 - 2016. N2 - We here compared results achieved by applying popular methods for reducing artifacts in magnetoencephalography (MEG) and electroencephalography (EEG) recordings of the auditory evoked Mismatch Negativity (MMN) responses in healthy adult subjects. We compared the Signal Space Separation (SSS) and temporal SSS (tSSS) methods for reducing noise from external and nearby sources. Our results showed that tSSS reduces the interference level more reliably than plain SSS, particularly for MEG gradiometers, also for healthy subjects not wearing strongly interfering magnetic material. Therefore, tSSS is recommended over SSS. Furthermore, we found that better artifact correction is achieved by applying Independent Component Analysis (ICA) in ...
A new method to reduce artifacts (MAR), produced by high-density objects, especially metal implants (MI), in X-ray CBCT is presented. MIs located in the field of view (FOV) result in artifacts influencing clinical diagnostics and treatments. The novel method reduces metal artifacts by virtually replacing MIs by tissue objects of the same shape. This corrected data can be reconstructed with significantly reduced artifacts. After reconstruction, the segmented 3D MIs were re-inserted into the corrected 3D volume. The method was developed for mobile C-arm CBCTs, where misalignments between original 2D data and forward projections must be adjusted before correction ...
Color interpolation is still the most used method for image upsampling, since it offers the simplest and therefore fastest algorithms. However, in recent years research concentrated on other techniques to counter the shortcomings of interpolation techniques (like color artifacts or the fact that interpolation does not take statistics into account), while interpolation itself has ceased to be an active research topic. Still, current interpolation techniques can be improved. Especially it should be possible to avoid color artifacts by carefully choosing the correct interpolation schemes. In this paper we derive mathematical constraints which need to be fulfilled to reach an artifact-free interpolation, and use these to develop an interpolation method which is basically a self-configuring cubic spline.. ...
Background: The aim of this study was to determine the impact of respiratory motion correction on SPECT MPI and on defect detection using a phantom assembly. Methods: SPECT/CT data were acquired using an anthropomorphic phantom with inflatable lungs and with an ECG beating and moving cardiac compartment. The heart motion followed the respiratory pattern in the cranio-caudal direction to simulate normal or deep breathing. Small or large transmural defects were inserted into the myocardial wall of the left ventricle. SPECT/CT images were acquired for each of the four respiratory phases, from exhale to inhale. A respiratory motion correction was applied using an image-based method with transformation parameters derived from the SPECT data by a non-rigid registration algorithm. A report on defect detection from two physicians and a quantitative analysis on MPI data were performed before and after applying motion correction. Results: Respiratory motion correction eliminated artifacts present in the ...
3-D optical coherence tomography (OCT) has been extensively investigated as a potential screening and/or surveillance tool for Barretts esophagus (BE). Understanding and correcting motion artifact may improve image interpretation. In this work, the motion trace was analyzed to show the physiological origin (respiration and heart beat) of the artifacts. Results showed that increasing balloon pressure did not sufficiently suppress the physiological motion artifact. An automated registration algorithm was designed to correct such artifacts. The performance of the algorithm was evaluated in images of normal porcine esophagus and demonstrated in images of BE in human patients.. ©2011 Optical Society of America. Full Article , PDF Article ...
The spinal cord is the main pathway for information between the central and the peripheral nervous systems. Non-invasive functional MRI offers the possibility of studying spinal cord function and central sensitisation processes. However, imaging neural activity in the spinal cord is more difficult than in the brain. A significant challenge when dealing with such data is the influence of physiological noise (primarily cardiac and respiratory), and currently there is no standard approach to account for these effects. We have previously studied the various sources of physiological noise for spinal cord fMRI at 1.5T and proposed a physiological noise model (PNM) (Brooks et al., 2008). An alternative de-noising strategy, selective averaging filter (SAF), was proposed by Deckers et al. (2006). In this study we reviewed and implemented published physiological noise correction methods at higher field (3T) and aimed to find the optimal models for gradient-echo-based BOLD acquisitions. Two general techniques were
To develop a no-reference video quality model, it is important to know how the perceived strengths of artifacts are related to their physical strengths and to the perceived annoyance. When more than one artifact is present, it is important to know whether and how its corresponding perceived strength depends on the presence of other artifacts and how perceived strengths combine to determine the overall annoyance. We study the characteristics of different types of artifacts commonly found in compressed videos. We create artifact signals predominantly perceived as blocky, blurry, ringing, and noisy and combine them in various proportions. Then, we perform two psychophysical experiments to independently measure the strength and overall annoyance of these artifact signals when presented alone or in combination. We analyze the data from these experiments and propose models for the overall annoyance based on combinations of the perceptual strengths of the individual artifact signals. We also test the ...
studies of the past are enhanced when an artifact is clearly associated with an intact archaeological context. Artifacts which lack a defined archaeological findspot or provenience have a greater potential to undermine the integrity of archaeological heritage in view of the possibility of admitting suspect artifacts into archaeological heritage. Looting is an illegal act that breaks the association between artifact and context. A looted artifact may be considered stolen property. Therefore, archaeological heritage that is looted is more likely to travel through illicit channels of distribution and/or exportation, which involve processes that may mask or confuse the identification of the artifact or its true findspot ...
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The aim of this study was to assess the potential of monoenergetic computed tomography (CT) images to reduce beam hardening artifacts in comparison to standard CT images of dental restoration on dental post-mortem CT (PMCT). Thirty human decedents (15 male, 58 ± 22 years) with dental restorations were examined using standard single-energy CT (SECT) and dual-energy CT (DECT). DECT data were used to generate monoenergetic CT images, reflecting the X-ray attenuation at energy levels of 64, 69, 88 keV, and at an individually adjusted optimal energy level called OPTkeV. Artifact reduction and image quality of SECT and monoenergetic CT were assessed objectively and subjectively by two blinded readers. Subjectively, beam artifacts decreased visibly in 28/30 cases after monoenergetic CT reconstruction. Inter- and intra-reader agreement was good (k = 0.72, and k = 0.73 respectively). Beam hardening artifacts decreased significantly with increasing monoenergies (repeated-measures ANOVA p , 0.001). ...
title,Fossil File Formats,/title, ,h1 align=center, Fossil File Formats ,/h1, The global state of a fossil repository is kept simple so that it can endure in useful form for decades or centuries. A fossil repository is intended to be readable, searchable, and extensible by people not yet born. The global state of a fossil repository is an unordered set of ,i,artifacts,/i,. An artifact might be a source code file, the text of a wiki page, part of a trouble ticket, or one of several special control artifacts used to show the relationships between other artifacts within the project. Each artifact is normally represented on disk as a separate file. Artifacts can be text or binary. In addition to the global state, each fossil repository also contains local state. The local state consists of web-page formatting preferences, authorized users, ticket display and reporting formats, and so forth. The global state is shared in common among all repositories for the same project, whereas the local state is ...
ePortfolio is a repository for digital artifacts that represent your learning. You may upload or create artifacts on any number of topics and at any stage of completion. An artifact may be a document, graphic, audio file, video file, presentation, or other form of digital media. You may upload files from a personal computer or storage device; import items from a course; link to a website; create an HTML file; fill out a form created by your institution; or record an audio file directly within ePortfolio.. Instead of viewing your artifacts as complete examples, consider them as ongoing projects and continuously revise them as you develop new skills and understandings. This way your portfolio is a true reflection of your skills and achievements.. ...
BACKGROUND: Magnetic resonance angiogram (MRA) of the brain is a widely employed non-invasive test to diagnose aneurysms. However, its overall accuracy is less than digital subtraction angiography and is prone to give false-positive or false-negative results. False-negative results can be seen with hemorrhage, lipoma, dermoid, posterior lobe of the pituitary gland, and the flow artifacts. PURPOSE: To describe the findings associated with false aneurysms in the anterior communicating artery on the time of flight MRA and review the physical principles behind this artifact. MATERIAL AND METHODS: This short series comprises of four patients whose MRA showed suspicious aneurysms in the region of the anterior communicating artery (ACOM) on time of flight MRA. RESULTS: Two patients underwent catheter angiogram and the other two patients had computed tomography angiogram. None of these cases proved to have aneurysms and normal anterior communicating arteries were seen in all the patients. The findings on the MR
In fMRI, activation is detected because of the blood oxygen level-dependent (BOLD) effect as deoxyhemoglobin concentration changes in regions of increased neuronal activity. T2*-weighted images are used to detect the BOLD effects in functional MR imaging (fMRI) mapping. However, the same T2* weighting, which forms the basis for signal intensity on fMRI, is also the source of potential susceptibility artifacts. The BOLD effect may not be detected in regions of the brain with large susceptibility artifacts, caused by internal static local field gradients that distort the image or attenuate the signal intensity (1-4). Susceptibility artifacts sufficient to reduce the BOLD effect occur at tissue interfaces such as that between air and brain, and affect the sensitivity of fMRI in the inferior lateral temporal lobes (including part of fusiform gyrus) and the inferior medial frontal lobes (medial orbital gyri and gyrus rectus) (2, 4, 5). In addition, susceptibility artifacts may occur secondary to ...
This quilt was for a trunk show for my work. It is one of my favorites I have done so far just because I am so in love with the fabric. The fabric line I used was Garden Grove by Kim Diehl. The pattern is in a book called Simply Fat Quarters by Its so Emma. The pattern was called Retreat. In case you are interested in checking out this quilt it is at Elaines Quilt Block in Cottonwood Heights, UT. There are a bunch of other quilts on display not only for this quilt show we did but also just a lot of lovely quilts around the shop. There are usually kits available for all of the quilts on display. I love how rich the colors are. This is a very fun pattern. The quilting that was done on this quilt is absolutely exquisite. I am so happy with how this quilt turned out. I brought 2 more quilts for this specific trunk show but unfortunately didnt take a picture before they were hung in the store. I look forward to bringing this quilt home ...
Examples of shared artifacts include Watson & Cricks Tinker-Toy DNA model. Each scientist would work on the model separately, then use grad students to carry the model around to his partner to express certain ideas. Both Compaq Computer and Southwest Airlines were reportedly established after their founders wrote their ideas down together on a table napkin, another shared artifact.. Both of these examples show an important factor in shared artifacts - if the shared artifact is not constrained then it will be too large or complex for the group to reach some measure of completion. Finishing the shared artifact really helps establish trust and the connections between the participants.. A shared artifact is also useful because flooding someone with information and terms gives no assurance that the recipient has gained knowledge of the subject. Instead, the act of creation confirms to both parties that the knowledge was successfully assimilated.. Another advantage to creating a shared artifact is ...
Autor: Kim, Kwang In et al.; Genre: Bericht; Online veröffentlicht: 2011; Open Access; Titel: Efficient Learning-based Image Enhancement : Application to|br/|Compression Artifact Removal and Super-resolution
Use of the MARA in our study significantly reduced artefacts around metallic implants on ivACT images and allowed for the delineation of surrounding structures.
MIME-version: 1.0 X-Mailer: Unknown (No Version) Content-type: multipart/alternative; boundary=Boundary_(ID_5HQm6aniGbkbsRDFTPmCng) --Boundary_(ID_5HQm6aniGbkbsRDFTPmCng) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Hello all. I could really use some help. Today, the pathologist called to say that she is seeing an artifact on the tissue. It looks like clusters of fine PCP organisms, only that they are not. Like someone took a very fine tip black marker and made circles around the cells. She said it is not on every slide. The slides she had me check were prostate needle bxs and an antrum bx. The only change in our routine has been that we are demonstrating a recycling system for alcohol and Xylene. I have not used the recycled product on the tissue processor or the H&E autostainer, but I have placed the recycled Xylene in our glass Coverslipper. I appreciate any and all comments. Thank you. Ryan Allan Memorial --Boundary_(ID_5HQm6aniGbkbsRDFTPmCng) Content-type: ...
Meaning what? -----Original Message----- From: David Orchard [mailto:[email protected]] Sent: Thursday, October 10, 2002 10:32 PM To: Cutler, Roger (RogerCutler); [email protected] Subject: RE: Artifacts Roger, The term artifact has been used in software for quite some time. Cheers, Dave -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Cutler, Roger (RogerCutler) Sent: Thursday, October 10, 2002 6:35 PM To: [email protected] Subject: Artifacts I would like to propose the following glossary entry: Artifact - 1) A remnant of something that is dead and gone, as in The shard of pottery found in the Yucatan was an artifact of the high Mayan civilization; 2) A defect or error in something otherwise regular and useful, as in Sixty cycle interference is a common artifact in monitors sited too close to power sources. Perhaps you can add other meanings for the word? I think you should if you are going to insist on using it. Listening to ...
Spinal cord functional imaging allows assessment of activity in primary synaptic connections made by sensory neurons relaying information about the state of the body. However, reported human data based on gradient-echo techniques have been largely inconsistent, with no clear patterns of activation emerging. One reason for this variability is the influence of physiological noise, which is typically not corrected for. By acquiring single-slice resting data from the spinal cord with a conventional gradient-echo EPI pulse sequence at TR=200 ms (critically sampled) and TR=3 s (under-sampled), we have characterised various sources of physiological noise. In 8 healthy subjects, the presence of physiologically dependent signal was explored using probabilistic independent component analysis (PICA). Based on the insights provided by PICA, we defined a new physiological noise model (PNM) based on retrospective image correction (RETROICOR), which uses independent physiological measurements taken from the subject to
CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): We propose a new measure, the method noise, to evaluate and compare the performance of digital image denoising methods. We first compute and analyze this method noise for a wide class of denoising algorithms, namely the local smoothing filters. Second, we propose a new algorithm, the non local means (NL-means), based on a non local averaging of all pixels in the image. Finally, we present some experiments comparing the NL-means algorithm and the local smoothing filters.
The purpose of this study was to quantify the effect of soft tissue artifact during three-dimensional motion capture and assess the effectiveness of an optimization method to reduce this effect. Four subjects were captured performing upper-arm internal-external rotation with retro-reflective marker sets attached to their upper extremities. A mechanical arm, with the same marker set attached, replicated the tasks human subjects performed. Artificial sinusoidal noise was then added to the recorded mechanical arm data to simulate soft tissue artifact. All data were processed by an optimization model. The result from both human and mechanical arm kinematic data demonstrates that soft tissue artifact can be reduced by an optimization model, although this error cannot be successfully eliminated. The soft tissue artifact from human subjects and the simulated soft tissue artifact from artificial sinusoidal noise were demonstrated to be considerably different. It was therefore concluded that the ...
Magnetic resonance imaging (MRI) is an imaging modality which provides good conditions for studies of flow and motion in the cardiovascular system. When using the phase contrast imaging technique, it is possible to perform velocity measurements in moving tissues and in blood. The acquired velocity data can be used for subsequent calculation of different parameters used for the assessment of cardiovascular function. These parameters rely on the accuracy and reproducibility of the velocity measurements.. This thesis includes an introduction to phase contrast imaging and how displacement artifacts may hamper the accuracy of velocity measurements using phase contrast imaging. A method for correction of this artifact was developed using the knowledge of the times at which velocity and spatial encoding are carried out in the pulse sequence. The elaboration of this correction method included modifications of a 3D phase contrast pulse sequence and development of post processing algorithms involving ...
CiteSeerX - Scientific articles matching the query: Image Denoising Methods for Tumor Discrimination in High-Resolution Computed Tomography
Corneal image (Fig. 1.c) with the smoothed pilot epithelial layer boundary overlaid. The second derivative plot of the pilot epithelial layer boundary is used to detect the regions of low-SNR for the epithelium excluding the center half of the image (Region B). A second derivative below 0 indicates that there is a positive inflection in the second derivative, which should not occur for normal cornea and thus indicates that the SNR may be low at this location. A second derivative below 0 in Region B often occurs near the central artifact due to the central artifact removal step which results in a linear interpolation between both sides of the central artifact ...
Mechanical Engineering and Green Manufacturing: The Comparison of Isotropic and Anisotropic Diffusion Techniques for Image Denoising