Noise characterization of block-iterative reconstruction algorithms. I. Theory

2000 ◽  
Vol 19 (4) ◽  
pp. 261-270 ◽  
Author(s):  
E.J. Soares ◽  
C.L. Byrne ◽  
S.J. Glick
Keyword(s):  
Iterative Reconstruction ◽  
Reconstruction Algorithms ◽  
Noise Characterization

scholarly journals A Voxel-Based Assessment of Noise Properties in Computed Tomography Imaging with the ASiR-V and ASiR Iterative Reconstruction Algorithms

2021 ◽  
Vol 11 (14) ◽  
pp. 6561
Author(s):  
Patrizio Barca ◽  
Daniela Marfisi ◽  
Chiara Marzi ◽  
Sabino Cozza ◽  
Stefano Diciotti ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Noise Reduction ◽  
Iterative Reconstruction ◽  
Reduction Potential ◽  
Ct Imaging ◽  
Reconstruction Algorithms ◽  
Computed Tomography Imaging ◽  
Tomography Imaging ◽  
First Time

Given the inherent characteristics of nonlinearity and nonstationarity of iterative reconstruction algorithms in computed tomography (CT) imaging, this study aimed to perform, for the first time, a voxel-based characterization of noise properties in CT imaging with the ASiR-V and ASiR algorithms as compared with conventional filtered back projection (FBP). Multiple repeated scans of the Catphan-504 phantom were carried out. CT images were reconstructed using FBP and ASiR/ASiR-V with different blending levels of reconstruction (20%, 40%, 60%, 80%, 100%). Noise maps and their nonuniformity index (NUI) were obtained according to the approach proposed by the report of AAPM TG-233. For the homogeneous CTP486 module, ASiR-V/ASiR allowed a noise reduction of up to 63.7%/52.9% relative to FBP. While the noise reduction values of ASiR-V-/ASiR-reconstructed images ranged up to 33.8%/39.9% and 31.2%/35.5% for air and Teflon contrast objects, respectively, these values were approximately 60%/50% for other contrast objects (PMP, LDPE, polystyrene, acrylic, Delrin). Moreover, for all contrast objects but air and Teflon, ASiR-V showed a greater noise reduction potential than ASiR when the blending level was ≥40%. While noise maps of the homogenous CTP486 module showed only a slight spatial variation of noise (NUI < 5.2%) for all reconstruction algorithms, the NUI values of iterative-reconstructed images of the nonhomogeneous CTP404 module increased nonlinearly with blending level and were 19%/15% and 6.7% for pure ASiR-V/ASiR and FBP, respectively. Overall, these results confirm the potential of ASiR-V and ASiR in reducing noise as compared with conventional FBP, suggesting, however, that the use of pure ASiR-V or ASiR might be suboptimal for specific clinical applications.

Noise Characterization of InAs Based Composite Channel DG -MOSHEMT with Different Gate Dielectrics

Silicon ◽  
2021 ◽  
Author(s):  
G. Sujatha ◽  
N. Mohankumar ◽  
R. Poornachandran ◽  
R. Saravana Kumar ◽  
Girish Shankar Mishra ◽  
...  
Keyword(s):  
Gate Dielectrics ◽  
Composite Channel ◽  
Noise Characterization

Using low-frequency noise characterization of AlGaN/GaN HEMT as a tool for technology assessment and failure prediction

2004 ◽  
Author(s):  
Jean-Guy Tartarin ◽  
Geoffroy Soubercaze-Pun ◽  
Abdelali Rennane ◽  
Laurent Bary ◽  
Robert Plana ◽  
...  
Keyword(s):  
Technology Assessment ◽  
Low Frequency ◽  
Failure Prediction ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Gan Hemt ◽  
Noise Characterization

Aerodynamic Noise Characterization of a Full-Scale Wind Turbine through High-Frequency Surface Pressure Measurements

2015 ◽  
Vol 14 (5-6) ◽  
pp. 729-766 ◽  
Author(s):  
Franck Bertagnolio ◽  
Helge Aa. Madsen ◽  
Christian Bak ◽  
Niels Troldborg ◽  
Andreas Fischer
Keyword(s):  
Wind Turbine ◽  
Surface Pressure ◽  
High Frequency ◽  
Full Scale ◽  
Aerodynamic Noise ◽  
Pressure Measurements ◽  
Noise Characterization

Flow noise characterization of gas–liquid two-phase flow based on acoustic emission

Measurement ◽  
2013 ◽  
Vol 46 (10) ◽  
pp. 3887-3897 ◽  
Author(s):  
Lide Fang ◽  
Yujiao liang ◽  
Qinghua Lu ◽  
Xiaoting Li ◽  
Ran Liu ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Noise ◽  
Noise Characterization

scholarly journals Evaluation of Algebraic Iterative Image Reconstruction Methods for Tetrahedron Beam Computed Tomography Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-14
Author(s):  
Joshua Kim ◽  
Huaiqun Guan ◽  
David Gersten ◽  
Tiezhi Zhang
Keyword(s):  
Computed Tomography ◽  
Iterative Reconstruction ◽  
Cone Angle ◽  
Iterative Algorithms ◽  
Projection Data ◽  
Reconstruction Algorithms ◽  
Reconstruction Methods ◽  
Large Cone Angle ◽  
Using Data ◽  
Dual Detector

Tetrahedron beam computed tomography (TBCT) performs volumetric imaging using a stack of fan beams generated by a multiple pixel X-ray source. While the TBCT system was designed to overcome the scatter and detector issues faced by cone beam computed tomography (CBCT), it still suffers the same large cone angle artifacts as CBCT due to the use of approximate reconstruction algorithms. It has been shown that iterative reconstruction algorithms are better able to model irregular system geometries and that algebraic iterative algorithms in particular have been able to reduce cone artifacts appearing at large cone angles. In this paper, the SART algorithm is modified for the use with the different TBCT geometries and is tested using both simulated projection data and data acquired using the TBCT benchtop system. The modified SART reconstruction algorithms were able to mitigate the effects of using data generated at large cone angles and were also able to reconstruct CT images without the introduction of artifacts due to either the longitudinal or transverse truncation in the data sets. Algebraic iterative reconstruction can be especially useful for dual-source dual-detector TBCT, wherein the cone angle is the largest in the center of the field of view.

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