Contents
Chapter 1 A brief history 1
1.1 Moiré effect 1
1.2 Moiré deflectometry 1
1.3 Moiré deflection tomography 2
1.4 The scope of the book 4
Chapter 2 Theoretical basis of flow field’s moiré deflection tomographydiagnosis 6
2.1 Dependence between refractive index and key parameters of flow fields 6
2.2 A new refractive index descriptive model of common plasma 8
2.2.1 Derivation based on Saha equation 8
2.2.2 Feasibility verification and analysis 11
2.3 A uniform refractive index description 15
2.3.1 Concept of equivalent particle number density 15
2.3.2 Rationality of the model 17
2.4 Physical essence of refractive index gradient in flow fields 22
2.4.1 Refractive index distributions 22
2.4.2 Physical essence analysis 23
2.5 A two-temperature refractive index model 26
2.5.1 Theory and rationality analysis 26
2.5.2 Method of measuring two temperatures 28
Chapter 3 Experiment of flow field’s moiré deflection tomography diagnosis 30
3.1 Effect of non-collimated optical path 31
3.1.1 Realization of experiment 31
3.1.2 Influence on temperature reconstruction 36
3.2 Effect of phase object’s position 38
3.2.1 Theoretical deduction by scalar diffraction theory 38
3.2.2 Intensity distribution and fringe equation 44
3.2.3 Verification by moiré fringe slope 49
3.3 Integrating moiré deflection tomography and shadowing method 51
3.3.1 Principle description and experimental design 51
3.3.2 Feasibility analysis 53
Chapter 4 Information extraction of moiré fringes 55
4.1 Preprocessing based on multiresolution analysis (MRA) 56
4.1.1 Basic theory 56
4.1.2 Results and comparison of three-level MRA 57
4.2 Phase extraction based on Gabor wavelet 63
4.2.1 Deduction of wrapped phase 64
4.2.2 Comparative analysis based on true phase results 66
4.3 Phase extraction based on Morlet wavelet 70
4.3.1 Fringe preprocessing and wrapped phase deduction 70
4.3.2 Phase information 73
4.3.3 Contribution of wavelet ridges 77
4.4 Phase denoising and unwrapping based on MRA 79
4.4.1 Theory and method 81
4.4.2 Effect of noise and discontinuity 84
4.4.3 Effect of wavelet basis function 87
4.4.4 Effect of decomposition level 88
4.4.5 Effect of iteration number 89
4.5 Application of deep learning 91
4.5.1 Impact of flow field’s position on moiré fringe analysis 92
4.5.2 Moiré fringe analysis across diverse carrier frequencies 104
Chapter 5 Measurement of key parameters for flow fields by moiré deflection tomography 117
5.1 Temperature measurement 117
5.1.1 Effect of composition 117
5.1.2 Effect of pressure 142
5.2 Electron number density measurement 148
5.2.1 Indirect measurement by one-wavelength moiré deflection tomography 148
5.2.2 Direct measurement by two-wavelength moiré deflection tomography 154
5.3 Composition ratio measurement 160
5.3.1 Two objects mixed 161
5.3.2 Three objects mixed 161
Chapter 6 Application of moiré deflectometry in atmosphere measurement 163
6.1 Measurement of atmospheric particle number density fluctuations 164
6.1.1 Principle analysis 164
6.1.2 Theoretical deduction 165
6.1.3 Experiment and arrival angles 167
6.1.4 Distribution of atmospheric particle number density fluctuations 173
6.2 Measurement of atmospheric refractive-index structure parameter 174
6.2.1 Situation analysis 174
6.2.2 Method description 176
6.2.3 Temporal and spatial distributions of deflection angle 178
6.2.4 Distribution of atmospheric refractive-index structure parameter 182
References 184