REAL TIME LASER BASED TOMOGRAPHY FOR PIPELINE FLOW MEASUREMENT
KHAIRIL AZMAN BIN MD AKHIR
This report is submitted in partial fulfillment of the requirements for the award of Bachelor of Electronic Engineering (Industrial Electronic) With
Honours
Faculty of Electronic and Computer Engineering Universiti Teknikal Malaysia Melaka
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UNIVERSTI TEKNIKAL MALAYSIA MELAKA
FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA II
Tajuk Projek : ………
Sesi
Pengajian :
Saya ……….. (HURUF BESAR)
mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:
1. Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.
2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara institusi
pengajian tinggi.
4. Sila tandakan ( √ ) :
SULIT*
*(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)
TERHAD** **(Mengandungi maklumat terhad yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD
Disahkan oleh:
__________________________ ___________________________________
(TANDATANGAN PENULIS) (COP DAN TANDATANGAN PENYELIA)
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“I hereby declared that this report entitled Real Time Laser Based Tomography System for Pipeline Flow Measurement is my work except for the works that has
been cited clearly in the references.”
Signature : ………
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“I hereby declared that I have read this report and my opinion this report is sufficient in terms of the scope and quality for the award the Bachelor of
Electronic Engineering (Industrial Electronic) with Honours”
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“This project is dedicated to my beloved parents, siblings, friends and lecturer
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ACKNOWLEDGEMENT
Praise is to Allah, the Cherisher and Sustainer of the worlds. With his permission I have completed this thesis.
My deep appreciation and heartfelt gratitude goes to my supervisor En Adie bin Mohd Khafe, for his kindness, constant endeavor, and guidance and the numerous moments of attention he devoted throughout this work.
A special thanks also to all my colleges that help me all the way through the works and development of this project and thesis. Without their support and friendship, my journey will be sorrow.
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ABSTRACT
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ABSTRAK
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TABLES OF CONTENTS
CHAPTER TITLE PAGE
TITLE i
PSM II REPORT STATUS ii
DECLARATION iii
SUPERVISOR APPROVAL iv
DEDICATION v
ACKNOWLEDGEMENTS vi
ABSTRACT vii
ABSTRAK viii
TABLES OF CONTENTS ix
LIST OF TABLE xii
LIST OF FIGURES xiii
LIST OF APPENDICES xv
1 INTRODUCTION
1.1 Project introduction 1
1.2 Project background 3
1.3 Problem statement 5
1.4 Objective of the project 6
1.5 Scope of work 6
1.6 Methodology 7
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2 LITERATURE REVIEW
2.1 An overview of process tomography 9
2.2 Tomography sensors 10
2.2.1 Electrical Capacitance Tomography (ECT) 11 2.2.2 Electrical Resistance Tomography (ERT) 13 2.2.3 Electrical Impedance Tomography (EIT) 14
2.2.4 Ultrasonic Tomography 15
2.2.5 X-ray tomography 15
2.2.6 Optical Tomography 16
2.2.7 Electrical Charge Tomography 17 2.3 Application of Process Tomography 19
2.4 Optical projection 22
2.5 LabVIEW software 25
3 METHODOLOGY
3.1 Introduction 27
3.2 Optical Tomography System 27
3.2.1 Selection of Optical Sensor 29
3.2.2 Laser Source 31
3.2.3 Signal Conditioning Circuit 32
3.3 PCB layout 34
3.4 PCB Development 35
3.5 Software Development 37
3.5.1 Initialize software with data acquisition 39
3.5.2 Acquiring data 40
3.5.3 Processing data 41
3.5.4 Image construction 42
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4 RESULT AND DISCUSSION
4.1 Introduction 44
4.2 Circuit simulation 44
4.3 Receiver circuit test 46
4.4 Receiver circuit PCBA test 47
4.5 The measurement system test 49
4.5.1 Result for no object 50
4.5.2 Result for test object one 51 4.5.3 Result for test object two 52 4.5.4 Result for test object three 53
4.6 Real time performance 54
4.7 Discussion 55
5 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 58
5.2 Recommendations 59
REFERENCES 60
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LIST OF TABLES
TABLE TITLE PAGE
Table 3.1 Levels of VI’s 38
Table 4.1 Simulation result 45
Table 4.2 Result for circuit construction 47
Table 4.3 Output for receiver circuit 48
Table 4.4 Voltage reading for no object 50
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LIST OF FIGURES
FIGURE TITLE PAGE
Figure 2.1 Overview of Process Tomography 10
Figure 2.2 ECT Measurement Circuits 12
Figure 2.3 Diagram showing the electrical model of EIT 14 Figure 2.4 Types of projections for optical tomography 24
Figure 3.1 Optical Imaging System 28
Figure 3.2 Pipeline model arrangement 28
Figure 3.3 BPX 65 Photodiode 30
Figure 3.4 Laser Pointer 31
Figure 3.5 Optical Receiving Circuit 32
Figure 3.6 PCB design for receiver circuit 33
Figure 3.7 PCB fabrication step 35
Figure 3.8 PCB after fabrication and drill 36
Figure 3.9 PCBA for receiver circuit 36
Figure 3.10 The Data Translation VI role 37
Figure 3.11 Flow of programming 39
Figure 3.12 DT Get Board Selection VI 40
Figure 3.13 DT Shutdown VI 40
Figure 3.14 DT AI Sample Channels VI 40
Figure 3.15 Processing Block 41
Figure 3.16 Summing Loop Block 42
Figure 3.17 Image Construction Block 43
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Figure 4.1 The Simulation Circuit 45
Figure 4.2 Circuit at full laser exposure 46
Figure 4.3 Circuit no laser exposure 46
Figure 4.4 Circuit at 50% laser exposure 47
Figure 4.5 Receiver circuit testing 48
Figure 4.6 The measurement system 49
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LIST OF APPENDICES
NO TITLE PAGE
Appendix A LabVIEW program block 61
Appendix B BPX 65 datasheet 62
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CHAPTER 1
INTRODUCTION
1.1 Project Introduction
There are various definitions to describe the word ‘Tomography’. Originally, the word is derived from the combinations of Greek words; ‘Tomo’ which is means ‘to slice’ or ‘cutting’ section, and ‘Graph’ that means ‘image’ or ‘drawing’. Moreover, the Oxford English dictionary defines tomography as: “Radiography in which an image of a predetermined plane in the body or other object is obtained by rotating the detector and the source of radiation in such a way that points outside the plane giving a blurred image”. Most people associate tomography with complex systems which are used to obtain images of internal parts of the human body.
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Tomography (IPT) or simply Process Tomography (PT). In addition to the use of tomography in the medical and industrial fields, it is also used in the fields of archaeology, biology, geophysics, materials science and other sciences. In most cases it is based on the mathematical procedure called homographic reconstruction.
In general, process tomography is a field to investigate the distribution of objects in a conveying pipe by placing several sensors around the vessel without interrupting the flow in the pipe; to acquire vital information in order to produce two or three dimensional images of the dynamic internal characteristics of process systems. The output signal from the sensors will be sent to the computer via an interfacing system. The computer will receive the signal from the respective sensors to perform data processing and finally construct a cross-section flow image in the pipe through image reconstruction algorithms. With further analysis, the same signal can be used to determine the concentration, velocity and mass-flow rate profile of the flows over a wide range of flow regimes by providing better averaging in time and space through multi-projections of the same observation. Such information can assist in the design of process equipment, verification of existing computational modeling and simulation techniques, or to assist in process control and monitoring.
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Optical tomography is an attractive method since it may prove to be less expensive, have a better dynamic response, and more portable for routine use in process plant other than radiation-based tomography methods such as positron emission, nuclear magnetic resonance, gamma photon emission and x-ray tomography. Its performance is also independent of temperature, pressure and viscosity of fluid (S. Ibrahim et al., 2000).
The optical tomography detect the flowing particle by the principle that the particle will cause the light emit from the transmitter to been deflect by the particle. The deflected light will cause the lesser the light that will be obtains by the receiver. Then, the receiver signal conditioning circuit will translate the condition of the receiver in term of signal or voltage. This process will continue and reoccur in cycle.
1.2 Project Background
Process tomography provides several methods of obtaining the concentration profile of a process. It has become one the vast growing technologies nowadays, and it can be applied to many types of processes and unit operation, including pipelines, stirred reactors, fluidized beds, mixers, and separators. Depending on the sensing mechanism used, it is non-invasive, inert, and non-ionizing.
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For this project, the image reconstruction is based on Linear Back Projection (LBP) algorithm. The LBP algorithm was originally designed for x-ray tomography, and then became the simplest and most common used in image reconstruction. Flow imaging measurements for this project will be done using on-line (real time). For on-line measurements, many performance aspects must be considered such as hardware performance, data acquisition system, algorithm performance and software programming. The quality of images obtained depends on the number of sensors used in measurements that will create the sensitivity matrix for the sensors. The input channel of the data acquisition system also has to be increased with the increase in the number of sensors used.
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1.3 Problem Statement
These days, various pipes and vessels are used in process, and it is difficult to know what type of flow is inside them especially without interrupting the process. Thus, the systems have to be developed whereby the system will be able to view objects within these pipes without interrupting the flow.
The process tomography system requires the knowledge of various disciplines such as instrumentation process, and optics to assist in the design and development of the system. Thus, more information gathering is required to gain the enough information about this system requirements and the design. The way around this problem would be to place sensing electronics around the actual pipe or vessel, where the system will using laser based detection system.
By using these sensing electronics, we are able to take measurements and recreate an image of what is contained within the vessel or pipe. Electronics of this nature needs to be created such that it is affordable and easy to operate. A laser source is used to emit the laser beam through the pipe, while optical receiver in the other end will pick up this beam and convert the laser beam intensity into a current that furthermore will be converted to voltage by a current to voltage converter. Various types of current to voltage converter needed to be built, implemented and tested for suitability and sensitivity.
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The process involves projecting a laser beam through some medium from one boundary point and detecting the level of light received at another boundary point. The Silicon Phototransistor transducer was used to measure the laser beam intensity. The software that acquire the data from the data acquisition system will
1.4 Objective of The Project
Mainly, the objective of this project is to:
i) Data gathering and information collection regarding the project
ii) To select the circuit and design the circuit for the receiver and transmitter circuit.
iii) To design and implement signal conditioning circuits that are effective for receiving and processing the signals
iv) To obtain the components and hardware for the project. v) To understand the image reconstruction algorithm.
vi) To develop program using LabVIEW that can display the concentration profiles for object flow in real time manner.
1.5 Scope of Work
To make sure the objective of the project can be achieved, the following scope of work is identified. The main criteria that needed are to obtain the data from the sensor and processed the data to computer. Below is the scope of work that has been identified:
i. Familiarization with the operation and performance of optical tomography systems.
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iii. To design, construct, and test signal conditioning circuits to process the signals obtained from sensors.
iv. To develop a program using LabVIEW to reconstruct a cross sectional images in order to determine the concentration profiles of the flowing particle inside the pipe.
1.6 Methodology
This project began with the research of the proposed title. The result of that research is then discussed with the supervisor. Once we have agreed with the supervisor on the title, the background of study for this project is obtained by researching. Here, theories about this project are studied and analyzed. When the information gathering of the project has completed, the process of designing the system can be started. Here, suitable components, the circuit types and the software that will be used are determined.
1.7 The Thesis Outline
This report shall explain the first part of the final year project, which is the research. What is done in the entire project is compiled in this report. This report is going to be the reference point with which it is going to be used in the next part of this project, constructing the hardware and software. All of contents of this report are useful to move this project to the next level. So it is important that the contents of this report to be thoroughly researched and put into place.
Chapter 1 introduces the project as a whole. The early and basic explanations are mentioned in this chapter. This chapter consists of the project’s objectives, statements of problems, scope of work, and the simplified methodology.
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system and a historical review about the evolvement of the process. Typical sensors used in process tomography are also discussed.
Chapter 3 explains how this project will be carried out or the methodology of the project. The ways and procedures in which this project is conducted will be described. This chapter also will enlighten the critical task and the flow of this project. What is researched and what needs to be done is explained in this chapter.
Chapter 4 focused on the result and discussion of this project. The result from the simulation and circuit construction is stated. Moreover, the results rational also will be explained. The reasons and setbacks that cause the project to be halted are discussed in this chapter. The expected results will also be mentioned in this chapter.
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CHAPTER 2
LITERATURE REVIEW
2.1 An overview of Process Tomography
Development of the process to be applied in an industrial field gave the word 'tomography' a well-defined term, which means a cross-sectional image of a particular area, while, process tomography means a cross-sectional image of a process. In a more specific definition, R. Abdul Rahim had defined process tomography as a technique involving the use of instruments which provide a cross sectional profile of the distribution of materials in a process vessel or pipeline (R. Abdul Rahim et al. 1995).
