Infrared Thermal Imaging

This new up-to-date edition of the successful handbook and ready reference retains the proven concept of the first, covering basic and advanced methods and applications in infrared imaging from two leading expert authors in the field. All chapters have been completely revised and expanded and a new chapter has been added to reflect recent developments in the field and report on the progress made within the last decade. In addition there is now an even stronger focus on real-life examples, with 20% more case studies taken from science and industry. For ease of comprehension the text is backed by more than 590 images which include graphic visualizations and more than 300 infrared thermography figures. The latter include many new ones depicting, for example, spectacular views of phenomena in nature, sports, and daily life.

Auteur

Michael Vollmer received his PhD degree for studies of clusters on surfaces, and his habilitation on optical properties of metal clusters from the University of Heidelberg, Germany. Later assignments were with the University of Kassel, Germany, the university of California in Berkeley, USA, as well as with various institutions in the United States and Asia during sabbaticals. His research interests include atmospheric optics, spectroscopy, infrared thermal imaging, and the didactics of physics. Professor Vollmer has authored one science book and co-authored a scientific monograph and about 230 scientific and didactical papers.

Klaus-Peter Möllmann received his PhD from the Humboldt University of Berlin, Germany, studying strongly doped narrow band semiconductors at low temperatures and later, for his habilitation, MCT photo detectors. He subsequently held positions with the Humboldt University and with several businesses in industry. Professor Möllmann's research interests include MEMS technology, infrared thermal imaging, and spectroscopy. He is the co-author of about 150 scientific and didactical papers.
Both authors are professors of experimental physics at the University of Applied Sciences in Brandenburg, Germany.

Contenu

Preface to Second Edition XVII

Preface to First Edition XIX

List of Acronyms XXIII

1 Fundamentals of Infrared Thermal Imaging 1

1.1 Introduction 1

1.2 Infrared Radiation 6

1.2.1 ElectromagneticWaves and the Electromagnetic Spectrum 6

1.2.2 Basics of Geometrical Optics for Infrared Radiation 10

1.2.2.1 Geometric Properties of Reflection and Refraction 10

1.2.2.2 Specular and Diffuse Reflection 12

1.2.2.3 Portion of Reflected and Transmitted Radiation: Fresnel Equations 12

1.3 Radiometry and Thermal Radiation 14

1.3.1 Basic Radiometry 15

1.3.1.1 Radiant Power, Excitance, and Irradiance 15

1.3.1.2 Spectral Densities of Radiometric Quantities 15

1.3.1.3 Solid Angles 16

1.3.1.4 Radiant Intensity, Radiance, and Lambertian Emitters 17

1.3.1.5 Radiation Transfer between Surfaces: Fundamental Law of Radiometry and View Factor 20

1.3.2 Blackbody Radiation 21

1.3.2.1 Definition 21

1.3.2.2 Planck Distribution Function for Blackbody Radiation 22

1.3.2.3 Different Representations of Planck's Law 24

1.3.2.4 Stefan-Boltzmann Law 26

1.3.2.5 Band Emission 26

1.3.2.6 Order-of-Magnitude Estimate of Detector Sensitivities of IR Cameras 29

1.4 Emissivity 31

1.4.1 Definition 31

1.4.2 Classification of Objects according to Emissivity 32

1.4.3 Emissivity and Kirchhoff's Law 32

1.4.4 Parameters Affecting Emissivity Values 34

1.4.4.1 Material 34

1.4.4.2 Irregular Surface Structure 34

1.4.4.3 Viewing Angle 35

1.4.4.4 Regular Geometry Effects 39

1.4.4.5 Wavelength 41

1.4.4.6 Temperature 42

1.4.4.7 Conclusion 43

1.4.5 Techniques toMeasure/Guess Emissivities for PracticalWork 44

1.4.6 Blackbody Radiators: Emissivity Standards for Calibration Purposes 45

1.5 Optical Material Properties in IR 49

1.5.1 Attenuation of IR Radiation while Passing throughMatter 50

1.5.2 Transmission of Radiation through the Atmosphere 51

1.5.3 Transmission of Radiation through Slablike SolidMaterials 54

1.5.3.1 Nonabsorbing Slabs 54

1.5.3.2 Absorbing Slabs 55

1.5.4 Examples of Transmission Spectra of Optical Materials for IR Thermal Imaging 56

1.5.4.1 Gray Materials in Used IR Spectral Ranges 56

1.5.4.2 Some Selective Absorbers 61

1.6 Thin Film Coatings: IR Components with Tailored Optical Properties 62

1.6.1 Interference ofWaves 63

1.6.2 Interference and Optical Thin Films 64

1.6.3 Examples of AR Coatings 65

1.6.4 Other Optical Components 66

1.7 Some Notes on the History of Infrared Science and Technology 69

1.7.1 Infrared Science 69

1.7.1.1 Discovery of Heat Rays and Atmospheric Absorption 69

1.7.1.2 Blackbodies and Blackbody Radiation 72

1.7.1.3 Radiation Laws 73

1.7.2 Development of Infrared Technology 76

1.7.2.1 Prerequisites for IR Imaging 77

1.7.2.2 Quantitative Measurements 84

1.7.2.3 Applications and Imaging Techniques 88

References 97

2 Basic Properties of IR Imaging Systems 107

2.1 Introduction 107

2.2 Detectors and Detector Systems 107

2.2.1 Parameters That Characterize Detector Performance 108

2.2.2 Noise Equivalent Temperature Difference 110

2.2.3 Thermal Detectors 111

2.2.3.1 Temperature Change of Detector 111

2.2.3.2 Temperature-Dependent Resistance of Bolometer 112

2.2.3.3 NEP and D* forMicrobolometer 113

2.2.4 Photon Detectors 117

2.2.4.1 Principle of Operation and Responsivity 117

2.2.4.2 D* for Signal-Noise-Limited Detection 119

2.2.4.3 D* for Background Noise Limited Detection 120

2.2.4.4 Necessity to Cool Photon Detectors 123

2.2.5 Types of Photon Detectors 125

2.2.5.1 Photoconductors 125

2.2.5.2 Photodiodes 126

2.2.5.3 Schottky Barrier Detectors 128

2.2.5.4 Quantum Well IR Photodetectors 128

2.2.5.5 Recent Developments in IR Detector Technology 132

2.3 Basic Measurement Process in IR Imaging 142

2.3.1 Radiometric Chain 142

2.3.2 Wavebands for Thermal Imaging 146

2.3.3 Selecting the AppropriateWaveband for Thermal Imaging 147

2.3.3.1 Total Detected Amount of Radiation 148

2.3.3.2 Temperature Contrast-Radiation Changes upon Temperature Changes 151

2.3.3.3 Influence of Background Reflections 155

2.3.3.4 Influence of Emissivity and Emissivity Uncertainties 158

2.3.3.5 Potential use of Bolometers in MWor SWband 168

2.4 Complete Camera Systems 173

2.4.1 Camera Design - Image Formation 173

2.4.1.1 Scanning Systems 174

2.4.1.2 Staring Systems-Focal-Plane Arrays 176

2.4.1.3 Nonuniformity Correction 180

2.4.1.4 Bad Pixel Correction 186

2.4.2 Photon Detector versus Bolometer Cameras 186

2.4.3 Detector Temperature Stabilization and Detector Cooling 188

2.4.4 Optics and Filters 191

2.4.4.1 Spectral Response 191

2.4.4.2 Chromatic Aberrations 191

2.4.4.3 Field of View 192

2.4.4.4 Extender Rings 195

2.4.4.5 Narcissus Effect 196

2.4.4.6 Spectral Filters 199

2.4.5 Calibration 200

2.4.6 Camera Operation 204

2.4.6.1 Switch-On Behavior of Cameras 205

2.4.6.2 Thermal Shock Behavior 206

2.4.7 Camera Software - Software Tools 208

2.5 Camera Performance Characterization 209

2.5.1 Temperature Accuracy 209

2.5.2 Temperature Resolution - Noise Equivalent Temperature Difference (NETD) 210

2.5.3 Spatial Resolution - IFOV and Slit Response Function 213

2.5.4 Image Quality: MTF, MRTD, and MDTD 216

2.5.5 Time Resolution - Frame Rate and Integration Time 221

References 226

3 AdvancedMethods in IR Imaging 229

3.1 Introduction 229

3.2 Spectrally Resolved Infrared Thermal Imaging 229

3.2.1 Using Filters 230

3.2.1.1 Glass Filters 231

3.2.1.2 Plastic Filters 233

3.2.1.3 Influence of Filters on Object Signal and NETD 234

3.2.2 Two-Color or Ratio Thermography 236

3.2.2.1 Neglecting Background Reflections 237

3.2.2.2 Approximations of Planck's Radiation Law 24…