1Fundamentals of Remote SensingEdited and written by Noam LevinNovember 19991st Hydrographic Data Management course, IMO - International Maritime Academy,Trieste, ItalyRemote Sensing Laboratory, Geography Department, Tel Aviv University, IsraelGIS unit, the Society for the Protection of Nature in [email protected] of contentsI Thanks 7II Preface 81 Introduction 91.1 Definition 91.2 Comparison to maps, GIS, aerial photography / Photogrammetry, SONAR 101.2.1 Satellite Images Vs Maps 101.2.2 Remote Sensing Vs GIS 101.2.3 Remote Sensing Vs Aerial Photography / Photogrammetry 101.2.4 Remote Sensing Vs SONAR 111.3 Applications in general 121.3.1 Agriculture 121.3.2 Forestry 121.3.3 Geology 131.3.4 Hydrology 131.3.5 Sea Ice 141.3.6 Land Cover & Land Use 141.3.7 Mapping 141.3.8 Oceans & Coastal Monitoring 152 Electromagnetic radiation 172.1 Electromagnetic energy 172.2 Interaction mechanisms 172.3 Laws regarding the amount of energy radiated from an object 182.3.1 Planck Radiation Law 182.3.2 Wien’s displacement law 192.3.3 Black body concept, Emissivity and Radiant Temperature 202.4 Electromagnetic Spectrum 212.4.1 Wavelength bands 222.4.2 Atmosphere effects 222.4.2.1 Scattering 222.4.2.2 Absorption 232.4.3 Reflectance spectra 252.4.3.1 Mixtures 272.4.3.2 Grain Size Effects 282.4.3.3 The Continuum and Band Depth 302.4.3.4 Continuum-Removed Spectral Feature Comparison 312.4.3.5 Viewing Geometry 333 Sensors 343.1 History 343.2 Satellite Characteristics: Orbits and Swaths 343.3 Scanner Sensor Systems 373.4 Spatial Resolution, Pixel Size, and Scale 383.5 Spectral / Radiometric resolution 403.5.1 Spectral charaecteristics 403.5.1.1 Spectral range 413.5.1.2 Spectral bandwidth 423.5.1.3 Spectral sampling 443.5.1.4 Signal-to-noise ratio 453.6 Temporal Resolution 453.7 Overview of different sensors – satellites and airborne 463.7.1 Comparison Table 463.7.1.1 Weather Satellites/Sensors 473.7.1.1.1 GOES 473.7.1.1.2 National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiometer 4833.7.1.2 Land Observation Satellites/Sensors 483.7.1.2.1 Landsat Multispectral Scanner 483.7.1.2.2 Landsat Thematic Mapper 493.7.1.2.3 Systeme Probatoire d'Observation de la Terra (SPOT) High Resolution Visible Sensor 493.7.1.2.4 Indian Remote Sensing 503.7.1.2.5 IKONOS 513.7.1.3 Marine Observation Satellites/Sensors 523.7.1.3.1 Coastal Zone Colour Scanner (CZCS) 523.7.1.3.2 MOS 533.7.1.3.3 SeaWiFS 533.7.1.3.4 Laser fluorosensor - another kind of sensor 533.7.1.4 Hyperspectral sensors 533.7.1.4.1 Compact Airborne Spectrographic Imager CASI 543.7.1.4.2 Digital Airborne Imaging Spectrometer DAIS 7915 543.7.1.4.3 AVIRIS Airborne Visible InfraRed Imaging Spectrometer 543.7.1.5 Synthetic Aperture Radar Sensors 554 Corrections 564.1 Radiometric calibration 564.1.1 Main elements of sensor calibration 564.1.1.1 Absolute radiometric calibration – from radiance to DN and back 564.1.1.2 Uniformity calibration 574.1.1.3 Spectral calibration 574.1.1.4 Geometric calibration 584.1.2 Calibration approaches 584.1.2.1 Prelaunch calibration 584.1.2.2 Onboard calibration 594.1.2.3 Vicarious calibration 594.2 Atmospheric - from radiance to reflectance or to temperatute\emissivity 604.2.1 Calibrating images from different dates to like-values 624.2.2 Internal Average Realtive Reflectance (IARR) 634.2.3 Flat Field 634.2.4 Empirical line 634.2.5 Atmospheric modelling 644.2.5.1 Band transmittance computer models 664.2.5.2 Line-by-line models 674.2.5.3 MODTRAN 674.2.5.4 2nd simulation of satellite signal in the solar spectrum – 6s code 694.2.5.5 ATmospheric REMoval program (ATREM) 704.2.5.6 ATCOR 724.2.6 Temperature calibration of images 734.2.7 Thermal properties of materials 734.2.8 Retrieval of temperature and emissivity from radiance in thermal images 774.3 Geometric corrections 794.3.1 Geometric registration 804.3.1.1 Plane transformations 814.3.1.2 Polynomial transformations 834.3.1.3 Triangulation 834.3.1.4 Ground Control Points 844.3.1.5 Resampling 854.3.1.6 Relief displacement 864.3.2 LANDSAT – geometric characteristics 904.3.2.1 TM geometric accuracy 904.3.2.2 TM data processing levels 904.3.2.3 Raw data 904.3.2.4 System corrected products 904.3.2.5 Geocoded products 914.3.2.6 Level A – without ground control points 914.3.2.7 Level B – with ground control points 9144.3.2.8 Level C – with ground control points plus DTM 914.3.3 SPOT – processing levels 924.3.3.1 Level 1A – no geometric correction 924.3.3.2 Level 1B - compensating internal geometric distortions 924.3.3.3 Level 1AP - Photographic product for photogrametric use withanalogue devices 924.3.3.4 Level 2A – entry level for cartographic products – projected,no control points 934.3.3.5 Level 2B – geocoded product, projected, with ground control points 934.3.3.6 Level ORTHO - The ultimate level of preprocessing for the bestcartographic accuracy: correction of the residual parallax errorsbrought by the relief 934.3.4 Parametric Geocoding (based on the PARGE alogrithm) 945 Image processing 985.1 Storage formats 985.2 Image enhancment: 1005.2.1 Histogram, stretching, colour palettes 1015.2.1.1 Contrast enhancement 1015.2.1.1.1 Linear Stretch 1015.2.1.1.2 Histogram equalization 1025.2.1.1.3 Piece-wise linear stretch 1025.2.1.2 RGB false colour composit 1045.2.1.2.1 Colour Definition Models, fusion of TM and SPOT 1045.2.1.2.1.1 Colour Definition Models 1045.2.1.2.1.2 Red, Green, and Blue (RGB) 1045.2.1.2.1.3 Hue, Saturation, and Lightness (HSL) 1055.2.1.2.1.4 CMYK Model 1055.2.1.2.1.5 Fusion by HSV Transformation 1055.2.1.3 Spatial filters – noise reduction (low-pass), edge enhancment (high-pass) 1065.2.1.3.1 The basic principles of a filter 1065.2.1.3.2 Low pass filters 1075.2.1.3.3 High pass filters 1105.3 Multi-band operations 1135.3.1 Image ratios: Brightness variations 1135.3.2 Normalized Difference Vegetation Index 1145.3.3 Principal components analysis 1145.3.4 Image classification 1175.3.4.1 Density slicing 1175.3.4.2 Multi-spectral image classification 1185.3.4.2.1 Supervised Classification 1195.3.4.2.1.1 Sampling 1195.3.4.2.1.2 Classification 1195.3.4.2.1.3 Accuracy assessment 1215.3.4.2.2 Unsupervised classification (clustering) 1265.3.5 Unmixing 1265.3.5.1 Modeling mixed spectra 1265.3.5.2 Practical unmixing methods 1276 Active Remote Sensing 1296.1 Side Looking Airborne Radar (SLAR): 1296.1.1 Frequencies 1326.1.2 Polarization 1336.1.3 Viewing Geometry and Spatial Resolution 1336.1.4 Radar