SECTION 4 TARGETS AND BACKGROUNDS 13 Atmospheric Effects 13.1 Atmospheric constituents 13.1.1 Water vapor 13.1.2 Aerosols 13.2 Atmospheric codes 13.2.1 LOWTRAN, MODTRAN, and HITRAN 13.2.2 MATISSE 13.3 Visible average transmittance 13.4 Infrared average transmittance 13.4.1 MWIR versus LWIR 13.4.2 Navy model 13.4.3 Land-based systems: horizontal path 13.4.4 Land-based systems: slant path 13.5 Weather conditions 13.5.1 Rain and snow 13.5.2 Probability of occurrence 13.6 Scattering and path radiance 13.6.1 Infrared 13.6.2 Visible contrast transmittance 13.7 Obscurants 13.8 Referencesġ4 Target Signatures 14.1 Target contrast 14.2 Targets in the IR 14.2.1 Area-weighted ΔT 14.2.2 Diurnal variations 14.2.3 Environmental modifiers 14.2.4 Active targets 14.3 Targets in the visible/NIR/SWIR 14.4 Target signature modeling 14.5 References SECTION 2 IMAGING SYSTEM CHAIN ANALYSIS: MTF APPROACHĤ Linear System Theory 4.1 Linear filter theory 4.2 Optical transfer function 4.3 MTF definition 4.4 Spatial frequency 4.4.1 Object and image spatial frequencies 4.4.2 Observer spatial frequency 4.5 Separability 4.6 Phase shifts 4.7 Final word 4.8 Referencesĥ Staring Array MTFs 5.1 Optics OTF 5.1.1 Diffraction-limited OTF 5.1.2 Central obscuration 5.1.3 Rectangular aperture 5.1.4 Non-circular apertures 5.1.5 Anamorphic optics 5.1.6 Aberrations 5.1.7 Defocused optics 5.1.8 Tolerancing 5.2 Detectors 5.2.1 Rectangular detectors 5.2.2 Non-square detectors 5.2.3 Visible color cameras 5.2.4 Diffusion 5.2.5 Charge transfer efficiency 5.2.6 TDI mismatch 5.3 Flat-panel displays 5.4 Eye MTF 5.5 ReferencesĦ Environmental MTFs 6.1 Motion 6.1.1 Linear motion 6.1.2 Sinusoidal motion 6.1.3 Random motion (jitter) 6.1.4 Low-frequency motion 6.2 Atmospheric turbulence 6.2.1 C N 2 6.2.2 Fried's coherence diameter 6.2.3 Horizontal path length 6.2.4 Slant path 6.2.5 Turbulence MTF 6.3 Aerosol MT 6.4 Referencesħ Two-Dimensional MTF 7.1 Optics 7.2 Motion 7.2.1 Linear motion 7.2.2 Sinusoidal motion 7.2.3 Random motion 7.3 Detector 7.4 Digital processing 7.5 Displays 7.6 The eye 7.7 Atmospheric turbulence 7.8 ReferencesĨ Sampling 8.1 Sampling theory 8.2 Staring array sampling frequency 8.3 Reconstruction 8.3.1 Spurious response 8.3.2 MTF "squeeze" 8.3.3 Resolved cycle contraction 8.4 Microscan 8.5 Super-resolution reconstruction 8.6 Sample-scene phase 8.7 Color filter arrays 8.8 Sampling artifacts 8.9 Can you see the sampling lattice? 8.10 Digital data representation 8.11 Referencesĩ Image Processing 9.1 z-transform 9.2 Digital filters 9.2.1 Unsharp filter 9.2.2 Averaging filter 9.3 Interpolation (electronic zoom) 9.3.1 Ideal interpolator 9.3.2 Lanczos interpolator 9.3.3 Pixel replication 9.3.4 Linear interpolation 9.3.5 Bilinear interpolation 9.4 Line-to-line interpolation 9.5 A noise reduction algorithm 9.6 Image restoration 9.7 Image enhancement 9.8 Final word 9.9 Referencesġ0 Detector Responsitivity 10.1 Filter transmission 10.2 Classical semiconductors 10.3 Novel semiconductors 10.4 Thermal detectors 10.5 Specific detectivity 10.6 Referencesġ1 Radiometry 11.1 Radiative transfer 11.2 Planck's blackbody law 11.3 Camera formula 11.3.1 Infrared sources 11.3.2 Visible, NIR, and SWIR sources 11.4 Point source 11.5 Photometry 11.6 Normalization 11.7 Referencesġ2 Signal-to-Noise Ratio 12.1 Common noise sources 12.1.1 Shot noise 12.1.2 Dark current 12.1.3 Multiplexer noise 12.1.4 Quantization noise 12.1.5 Non-scene photons 12.1.6 Spatial noise 12.2 NEDT 12.2.1 Background temperature 12.2.2 FPN 12.2.3 Variable integration time 12.2.4 Warm optics 12.2.5 Uncooled systems 12.3 NEΔρ 12.4 NEI 12.5 SNR optimization 12.6 Sun glints 12.7 Signal-to-clutter ratio 12.8 Three-dimensional noise model 12.9 Noise figure 12.10 Real systems 12.11 References Symbols and Acronyms SECTION 1 THE BASICSġ Introduction 1.1 System modeling 1.2 System applications 1.3 Nomenclature 1.4 System modeling 1.5 Staring array modeling 1.6 ReferencesĢ Imaging System Design 2.1 IR detectors 2.1.1 Detector classification 2.1.2 Specific detectors 2.2 Scanners 2.3 Staring arrays 2.4 IR system evolution 2.4.1 Common module systems 2.4.2 EOMUX systems 2.4.3 EMUX systems 2.4.4 Second-generation systems 2.4.5 Staring array systems 2.4.6 Third-generation systems 2.5 Visible system detectors 2.5.1 CCDs 2.5.2 CMOS 2.6 Image intensifiers (I 2 devices) 2.7 Intensified solid-state cameras 2.8 High-definition television 2.9 Referencesģ Fill Factor and Field of View 3.1 Pixels, datels, and disels 3.2 Fill factor 3.3 Field of view 3.4 Optical blur