Three-dimensional Density Reconstruction Analysis Method for Omni-directional Muography

2020 ◽  
Author(s):  
Seigo Miyamoto ◽  
Shogo Nagahara
Keyword(s):  
Spatial Resolution ◽  
Three Dimensional ◽  
Cosmic Ray ◽  
Inversion Method ◽  
Density Structure ◽  
Back Projection ◽  
Analysis Method ◽  
Filtered Back Projection ◽  
Linear Inversion ◽  
Reconstruction Methods

<p>Muography is the technique to observe the inner density structure of volcano by using cosmic-ray muons. In previous study, three-dimensional density reconstruction was attempted by using muography data from multiple directions (Tanaka et al., 2010, Rosas-Carbajal et al., 2017), but they could only get a few hundred meters of spatial resolution. To improve the spatial resolution, Nagahara and Miyamoto (2018) suggested omni-directional muography, putting ten or more observation points to surround the volcano.</p><p>  There are two types of three-dimensional density reconstruction methods from omni-directional muography observations, the linear inversion method (Rosas-Carbajal et al., 2017) and the filtered back projection (FBP) method (Nagahara and Miyamoto, 2018). The former is applicable even when the number of observation points is small, but requires many arbitrary parameters, while the latter has the characteristic that no arbitrary parameters are required but a certain number of observation points is required.</p><p>In this presentation, we show the results of a comparison between the two methods in simulation.</p>

scholarly journals Feasibility of three-dimensional density tomography using dozens of muon radiographies and filtered back projection for volcanos

2018 ◽  
Vol 7 (4) ◽  
pp. 307-316 ◽  
Author(s):  
Shogo Nagahara ◽  
Seigo Miyamoto
Keyword(s):  
Three Dimensional ◽  
Cosmic Ray ◽  
Exposure Period ◽  
Effective Area ◽  
Scoria Cone ◽  
Inversion Method ◽  
Back Projection ◽  
Initial Model ◽  
Filtered Back Projection ◽  
Using Data

Abstract. This study is the first trial to apply the method of filtered back projection (FBP) to reconstruct three-dimensional (3-D) bulk density images via cosmic-ray muons. We also simulated three-dimensional reconstruction image with dozens of muon radiographies for a volcano using the FBP method and evaluated its practicality. The FBP method is widely used in X-ray and CT image reconstruction but has not been used in the field of muon radiography. One of the merits of using the FBP method instead of the ordinary inversion method is that it does not require an initial model, while ordinary inversion analysis needs an initial model. We also added new approximation factors by using data on mountain topography in existing formulas to successfully reduce systematic reconstruction errors. From a volcanic perspective, lidar is commonly used to measure and analyze mountain topography. We tested the performance and applicability to a model of Omuroyama, a monogenetic scoria cone located in Shizuoka, Japan. As a result, it was revealed that the density difference between the original and reconstructed images depended on the number of observation points and the accidental error caused by muon statistics depended on the multiplication of total effective area and exposure period. Combining all of the above, we established how to evaluate an observation plan for volcanos using dozens of muon radiographies.

Demonstration of 11-directional muography in Omuro-yama Scoria cone, Izu, Japan

2020 ◽  
Author(s):  
Shogo Nagahara ◽  
Seigo Miyamoto ◽  
Kunihiro Morishima ◽  
Toshiyuki Nakano ◽  
Masato Koyama ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Three Dimensional ◽  
Cosmic Ray ◽  
Scoria Cone ◽  
Density Structure ◽  
Analysis Method ◽  
Future Plan ◽  
Lack Of Information ◽  
Baseline Diameter ◽  
Observation Results

<p>Muography is the method of determining inner bulk density structures of volcano by using cosmic-ray muons. When we get muography image from one direction, there is no spatial resolution along muon path. However, by observing from multiple directions, three-dimensional density structure can be obtained. In recent years, three-dimensional density reconstruction using two or three muographic images has been performed (Tanaka et al., 2010, Rosas-Carbajal et al., 2017), but they obtained three-dimensional density structure with only several hundreds of meters spatial resolution due to lack of information. To improve the spatial resolution, we suggested “omni-directional muography”, putting ten or more observation points to surround the volcano (Nagahara and Miyamoto, 2018), and we estimated its feasibility by simulation. On the other hand, in recent years, detectors for muography have become larger (Morishima et al., 2018, Olah et al., 2019), and a detector necessary for omni-directional muography can be prepared. Therefore, we demonstrated omni-directional muography in Omuro-yama Scoria cone, Izu, Japan.</p><p>Omuro-yama is a scoria cone formed by a single eruption. The mountain baseline diameter is about 1 kilometer and the height from base is 300 meters. The eruption has been investigated by sediment surveys (Koyano et al.,1996). This mountain has many advantages that are suitable for omnidirectional muography. 1) no mountains around Omuroyama, so no contamination of muon path except in the Omuroyama body. 2) easy to access the detector sites, 3) enough statistics of penetrating muons because of size. We started observing Omuro-yama in 2018. In 2018, we observed for two months from three directions using a 0.01 square meter emulsion detector. In 2019, we performed a three-month observation from eight directions using a 0.02 square meter emulsion detector. As a result of preliminary three-dimensional density reconstruction using the analysis method of Nishiyama et al. (2014), a region with a low density over 200 m in diameter was found under the crater. Currently, we are considering this result carefully. We plan to observe from 30 directions by 2021, including 11 points.</p><p>In this presentation, we report the latest analysis results of observation results from 11 directions and future plan.</p>

scholarly journals Efficient Strike Artifact Reduction Based on 3D-Morphological Structure Operators from Filtered Back-Projection PET Images

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7228
Author(s):  
Chun-Yi Chiu ◽  
Yung-Hui Huang ◽  
Wei-Chang Du ◽  
Chi-Yuan Wang ◽  
Huei-Yong Chen ◽  
...  
Keyword(s):  
Image Quality ◽  
Three Dimensional ◽  
Morphological Structure ◽  
Whole Body ◽  
Noise Distribution ◽  
Parallel Operation ◽  
Back Projection ◽  
Nuclear Medicine Imaging ◽  
Filtered Back Projection ◽  
Reconstruction Methods

Positron emission tomography (PET) can provide functional images and identify abnormal metabolic regions of the whole-body to effectively detect tumor presence and distribution. The filtered back-projection (FBP) algorithm is one of the most common images reconstruction methods. However, it will generate strike artifacts on the reconstructed image and affect the clinical diagnosis of lesions. Past studies have shown reduction in strike artifacts and improvement in quality of images by two-dimensional morphological structure operators (2D-MSO). The morphological structure method merely processes the noise distribution of 2D space and never considers the noise distribution of 3D space. This study was designed to develop three-dimensional-morphological structure operators (3D MSO) for nuclear medicine imaging and effectively eliminating strike artifacts without reducing image quality. A parallel operation was also used to calculate the minimum background standard deviation of the images for three-dimensional morphological structure operators with the optimal response curve (3D-MSO/ORC). As a result of Jaszczak phantom and rat verification, 3D-MSO/ORC showed better denoising performance and image quality than the 2D-MSO method. Thus, 3D MSO/ORC with a 3 × 3 × 3 mask can reduce noise efficiently and provide stability in FBP images.

scholarly journals Tests of a novel imaging algorithm to localize hidden objects or cavities with muon radiography

2018 ◽  
Vol 377 (2137) ◽  
pp. 20180063 ◽  
Author(s):  
L. Bonechi ◽  
G. Baccani ◽  
M. Bongi ◽  
D. Brocchini ◽  
N. Casagli ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Three Dimensional ◽  
Cosmic Ray ◽  
Real Data ◽  
Test Results ◽  
Back Projection ◽  
Imaging Algorithm ◽  
Muon Radiography ◽  
Points Of View ◽  
Large Material

A novel algorithm developed within muon radiography to localize objects or cavities hidden inside large material volumes was recently proposed by some of the authors (Bonechi et al. 2015 J. Instrum. 10 , P02003 ( doi:10.1088/1748-0221/10/02/P02003 )). The algorithm, based on muon back projection, helps to estimate the three-dimensional position and the transverse extension of detected objects without the need for measurements from different points of view, which would be required to make a triangulation. This algorithm can now be tested owing to the availability of real data collected both in laboratory tests and from real-world measurements. The methodology and some test results are presented in this paper. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.

Reconstruction of grain boundaries in polycrystals by filtered back-projection of diffraction spots

2003 ◽  
Vol 36 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Henning Friis Poulsen ◽  
Soeren Schmidt
Keyword(s):  
Grain Boundaries ◽  
Three Dimensional ◽  
Projection Algorithm ◽  
Reconstruction Method ◽  
X Rays ◽  
Back Projection ◽  
Filtered Back Projection ◽  
Mosaic Spread

A reconstruction method is presented for the generation of three-dimensional maps of the grain boundaries within powders or polycrystals. The grains are assumed to have a mosaic spread below 1°. They are mapped non-destructively by diffraction with hard X-rays, using a uniform mm2-sized beam. First the diffraction spots are sorted with respect to grain of origin by the indexing programGRAINDEX. Next, for each grain the reconstruction is performed by a variant of the filtered back-projection algorithm. The reconstruction method is verified by a simulation over ten grains. Using 64 reflections for each grain, sub-pixel accuracy is obtained. The potential of the method is outlined.

scholarly journals Optimization of Three-Dimensional (3D) Chemical Imaging by Soft X-Ray Spectro-Tomography Using a Compressed Sensing Algorithm

2017 ◽  
Vol 23 (5) ◽  
pp. 951-966 ◽  
Author(s):  
Juan Wu ◽  
Mirna Lerotic ◽  
Sean Collins ◽  
Rowan Leary ◽  
Zineb Saghi ◽  
...  
Keyword(s):  
Compressed Sensing ◽  
Iterative Reconstruction ◽  
Three Dimensional ◽  
Chemical Imaging ◽  
Reconstruction Technique ◽  
Back Projection ◽  
X Ray ◽  
Reconstruction Methods ◽  
Scanning Transmission ◽  
X Ray Absorption

AbstractSoft X-ray spectro-tomography provides three-dimensional (3D) chemical mapping based on natural X-ray absorption properties. Since radiation damage is intrinsic to X-ray absorption, it is important to find ways to maximize signal within a given dose. For tomography, using the smallest number of tilt series images that gives a faithful reconstruction is one such method. Compressed sensing (CS) methods have relatively recently been applied to tomographic reconstruction algorithms, providing faithful 3D reconstructions with a much smaller number of projection images than when conventional reconstruction methods are used. Here, CS is applied in the context of scanning transmission X-ray microscopy tomography. Reconstructions by weighted back-projection, the simultaneous iterative reconstruction technique, and CS are compared. The effects of varying tilt angle increment and angular range for the tomographic reconstructions are examined. Optimization of the regularization parameter in the CS reconstruction is explored and discussed. The comparisons show that CS can provide improved reconstruction fidelity relative to weighted back-projection and simultaneous iterative reconstruction techniques, with increasingly pronounced advantages as the angular sampling is reduced. In particular, missing wedge artifacts are significantly reduced and there is enhanced recovery of sharp edges. Examples of using CS for low-dose scanning transmission X-ray microscopy spectroscopic tomography are presented.

scholarly journals Feasibility of three-dimensional density tomography using dozens of muon radiographies and Filtered BackProjection for volcano

2018 ◽  
Author(s):  
Shogo Nagahara ◽  
Seigo Miyamoto
Keyword(s):  
Three Dimensional ◽  
Cosmic Ray ◽  
Exposure Period ◽  
Effective Area ◽  
Scoria Cone ◽  
Inversion Method ◽  
Filtered Backprojection ◽  
Initial Model ◽  
Dimensional Reconstruction ◽  
Using Data

Abstract. This study is the first trial to apply the method of filtered backprojection (FBP) method to reconstruct three-dimensional (3D) bulk density images via cosmic-ray muons, We also simulated three-dimensional reconstruction image with dozens of muon radiographies using FBP method for a volcano and evaluated its practicality. FBP method is widely used in X-ray and CT image reconstruction but has not been used in the field of muon radiography. One of the merits to use FBP method instead of ordinary inversion method is that it doesn't require an initial model, while ordinary inversion analysis need an initial model. We also added new approximation factors by using data on mountain topography into existing formulas to successfully reduce systematic reconstruction errors. From a volcanic perspective, airborne radar is commonly used to measure and analyze mountain topography. We tested the performance and applicability to the model of Omuroyama, a monogenetic scoria cone located in Shizuoka, Japan. As a result, it was revealed that the density difference between the original and reconstructed images depended on the number of observation points and the accidental error caused by muon statistics depended on the multiplication of total effective area and exposure period. Combining above all things, we established how to evaluate an observation plan for volcano using dozens of muon radiographies.

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