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Deparment : Physics

College : Science - Damietta

Degree : Ph D.

Author : Mohamed abdou Mohamed El-Morsy

 

Dissertation Title :

Computer-aid Analysis of Interference Patterns of Fibres and Polymers Using Automatic Fringe Analysis Methods

 

 

Dissertation Abstract  

 

The main assumption in this work is that both manual and automatic fringe analysis are used to analyze multiple-beam Fizeau fringes. Multiple-beam interference Fizeau fringe in transmission technique is used to measure the refractive index profile of drawn polyethylene fiber.

A general introduction to fiber, multiple-beam Fizeau fringes, and automatic fringe analysis are presented in chapter 1. Previous work on fiber investigation by interferometric method and previous work on image analysis techniques used to analyze

the interference fringe are presented in chapter 2.

Chapter 3 deals with the theoretical consideration of multiple-beam Fizeau fringe technique such as conditions of fringe formation. The mathematical expression of refractive index profile for multilayer fiber using multiple-beam Fizeau interferometer and the basic concepts of image processing and image analysis are presented in

this chapter.

In chapter 4, the interference fringe shift in the fiber region has been analyzed automatically using interactive algorithm. Plane polarized light vibrating parallel and perpendicular to the fiber axis are used to obtain the refractive index profiles for both cases. These profiles are used to determine some optical parameters such as the birefringence, the optical orientation function, the polarizability per unit volume

In chapter 5, the Fourier transform method is applied to analyze multiplebeam interference Fizeau fringes. The real part of inverse Fourier transform is used to estimate a theoretical pattern. This pattern coincides with the experimental one. Also a derivative sign binary image of the interference pattern is used in automated determination of the contour line of the fringe pattern regardless the quality of this pattern. A correlation between the pixel size and the accuracy of the measured fiber refractive index is presented.

In chapter 6, phase analysis method has been used with the Fourier transform technique to perform accurate and fast automatic measurement of fiber refractive index profile. The refractive index profiles of polyethylene fibers with different draw ratios are presented by two methods, fringe shift method and phase analysis method. A comparison between the obtained results is presented.

In chapter 7, some aspects concerning the subfringe integration method in interferogram analysis have been investigated and  modified. The modified algorithm, introduced in this work is capable of reconstructing the phase in the presence of noise or in the presence of errors in carrier frequency. The subfringe integration method was applied to analyze two computer simulated patterns of equispaced Fizeau fringes using N bucket integration. Also it is used to analyze multiple-beam Fizeau fringes. The refractive index profile of polyethylene fiber is obtained by using two methods, subfringe integration method, and Fourier transform method. A comparison between the obtained results using the maintained methods is presented. Nowadays,  nanotechnology was proposed to provide a fabrication processes with high level dimensional accuracy of the order of a few nanometers.

In chapter 8, Surface relief holograms were fabricated on azo-polymer films by the irradiation of interference laser fringes. The side-chain azo-polymer, poly-orange tom-1 ophoronediisocyanate, was used in this study. Recording characteristics of surface relief structures were investigated; they needed no post-treatment, and could be erased by heating or irradiating a uniform laser beam. The diffraction efficiency of the recorded hologram was markedly increased by corona charging. It was also controlled by irradiation of the laser beam (488nm) with corona charging. The general conclusions are presented in chapter nine.

 

Key Words

Optical Fiber, interference techniques, Image analysis, Image processing , Fourier transform

 

Points of interests  

 

(1 (1) Study the optical properties of the optical fibers

(2   (2) Investigate the structural parameters of the fiber

(3  (3) Using the automatic fringe analysis to analyze the interference fringe pattern

(4  (4) Determine the refractive index profile of regular and irregular fiber

(5  (5) Modify the mathematical expression for determining the refractive index profile

(6  (6) sing different types of interferometric to investigate the fibers

(7   (7) Using phase modulation to determine the physical properties of the polymeric and optical fibers.

(8   (8) etermine the phase distribution to investigate the bending optical fibers.

   

 

 

 
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