A Study on Forward and Inverse Problems for an Ultrasonic Tomography

2014 ◽  
Vol 70 (3) ◽  
Author(s):  
Mohd Hafiz Fazalul Rahiman ◽  
Ruzairi Abdul Rahim ◽  
Herlina Abdul Rahim ◽  
Zulkarnay Zakaria ◽  
Muhammad Jaysuman Pusppanathan
Keyword(s):  
Two Phase Flow ◽  
Reconstruction Algorithm ◽  
Projection Algorithm ◽  
Ultrasonic Tomography ◽  
Phase Flow ◽  
Back Projection ◽  
Two Phase ◽  
Tomographic Images ◽  
Linear Back Projection ◽  
Scanning Geometry

This paper studies the solution for inverse and forward problems for an ultrasonic tomography. Transmission-mode approach has been used for sensing the liquid/gas two-phase flow, which is a kind of strongly inhomogeneous medium. The imaging technique for two-phase flow using fan-shaped beam scanning geometry was presented. In this work, the tomographic images are derived from Back-Projection Algorithm. Some of the results based on the Linear Back-Projection algorithm (LBP) and the Hybrid Reconstruction algorithm (HR) was also presented.

Simulative Study of Two-Phase Homogenous and Isotropic Media Imaging using Magnetic Induction Tomography

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Zulkarnay Zakaria ◽  
Ibrahim Balkhis ◽  
Lee Pick Yern ◽  
Nor Muzakkir Nor Ayob ◽  
Mohd Hafiz Fazalul Rahiman ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
Magnetic Induction ◽  
Optical Tomography ◽  
Reconstruction Algorithm ◽  
Projection Algorithm ◽  
Back Projection ◽  
Two Phase ◽  
Excitation Coil ◽  
Magnetic Induction Tomography ◽  
Linear Back Projection

Magnetic induction tomography is a new non-invasive technology, based on eddy current discovery of electromagnetic induction by Michael Faraday. Through this technique, the passive electrical properties distribution of an object can be obtained by the use of image reconstruction algorithm implemented in this system. There are many types of image reconstruction that have been developed for this modality, however in this paper only two algorithms discussed, Linear Back Projection and Eminent Pixel Reconstruction. Linear Back Projection algorithm is the most basic type of image reconstruction. It is the simplest and fast algorithm out of all types of algorithms, whereas Eminent Pixel Reconstruction algorithm is an improved algorithm which provided better images and has been implemented in other modalities such as optical tomography. This paper has implemented Eminent Pixel Reconstruction in magnetic induction tomography applications and the performance is compared to Linear Back Projection based on the simulation of the fourteen types of simulated phantoms of homogenous and isotropic conductivity property. It was found that Eminent Pixel Reconstruction has produced better images relative to Linear Back Projection, however the images are still poor when the objects are located near to the excitation coil or sensor and it is worse when the distance between objects are near to each other.

Edge Detection Algorithm For Enhancement of Linear Back Projection Tomographic Images

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Jaysuman Pusppanathan ◽  
Mahdi Faramarzi ◽  
Fazlul Rahman Yunus ◽  
Nor Muzakkir Nor Ayob ◽  
Ruzairi Abdul Rahim ◽  
...  
Keyword(s):  
Edge Detection ◽  
Measurement Data ◽  
Detection Algorithm ◽  
Image Processing Technique ◽  
Projection Algorithm ◽  
Ultrasonic Tomography ◽  
Back Projection ◽  
Tomographic Images ◽  
Flow Monitoring ◽  
Linear Back Projection

Process tomography (PT) is a leading technique for multiphase flow measurement and flow monitoring systems in various fields. PT has the advantage of interpreting acquired measurement data and transforming it into visual tomographic images. The most common method of image reconstruction uses the linear back projection algorithm which often results in blurry images. This paper proposes an enhancement of the reconstructed images using an edge detection image processing technique to convolve with the original image. This filtering technique calculates approximation changes of the horizontal and vertical image derivatives, thus further enhancing image accuracy. Several ultrasonic tomography images were put into a simulation test to validate it. Hence, the image results are being assessed for its performance.

Image Reconstruction Algorithms For Ultrasonic Tomography

2012 ◽  
Author(s):  
Mohd Hafiz Fazalul Rahiman ◽  
Ruzairi Abdul Rahim ◽  
Herlina Abdul Rahim
Keyword(s):  
Image Reconstruction ◽  
Reconstruction Algorithm ◽  
Ultrasonic Tomography ◽  
Back Projection ◽  
Reconstruction Algorithms ◽  
Tomography System ◽  
Tomography Image ◽  
Real Objects ◽  
Linear Back Projection ◽  
Image Reconstruction Algorithms

Kertas ini membincangkan algoritma pembangunan imej bagi kegunaan dalam tomografi ultrasonik. Terdapat tiga jenis algoritma pembangunan iaitu Linear Back Projection, Hybrid Reconstruction dan Hybrid Binary Reconstruction. Algoritma tersebut telah diuji ke atas sistem tomografi ultrasonik berdasarkan kepada beberapa bayang yang telah dikenalpasti dan objek–objek sebenar. Prestasi algoritma tersebut telah di analisa dan bincangkan pada bahagian akhir kertas ini. Kata kunci: Algoritma pembangunan; tomografi ultrasonic; pemprosesan image; mabuk This paper presented image reconstruction algorithms for use in ultrasonic tomography. There are three types of reconstruction algorithms namely Linear Back Projection, Hybrid Reconstruction and Hybrid Binary Reconstruction. The algorithms have been evaluated on ultrasonic tomography system based on several known phantoms and real objects. The performance of the algorithms have been analysed and discussed at the end of the paper. Key words: Reconstruction algorithm; ultrasonic tomography; image processing

Liquid-Gas Two-Phase Flow Simulation for Flat Fan Nozzles

2014 ◽  
Author(s):  
Guibo Li ◽  
Yongsheng Lian ◽  
Matt Mersch ◽  
Chris Omalley ◽  
Adam Hofmann
Keyword(s):  
Adaptive Mesh Refinement ◽  
Two Phase Flow ◽  
Flow Simulation ◽  
Adaptive Mesh ◽  
Variable Density ◽  
Projection Algorithm ◽  
Phase Flow ◽  
Operating Pressure ◽  
Two Phase ◽  
Structured Adaptive Mesh Refinement

This paper focuses on the numerical simulation of two-phase flow near the outlet of flat fan nozzles under low operating pressure. The moment-of-fluid (MOF) method is used for the representation of the liquid gas interface and the directional split method is used for the advection of the interface. A variable density pressure projection algorithm is used for the fluid solver and a block structured adaptive mesh refinement (AMR) method is used to locally increase the resolution near interface. The internal geometry of the nozzle is defined by three parameters: nozzle inlet diameter D, V-cut or U-cut width W and V-cut or U-cut offset H. The effects of these three parameters on the fan exit angle and pressure loss through the nozzles are studied. Experiments are conducted to validate our simulation results. Finally, we give some conclusions about the modeling of the flat fan nozzle under low operating pressure based on our study.

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