Remote sensing

The Remote Sensing (English: Remote Sensing ) is the set of process for recovery of information on the earth's surface or other objects not directly accessible by measurement and interpretation of emanating from it (energy) fields. As an information carrier it is reflected or emitted electromagnetic radiation. [DIN 18716/3 ]

Unlike other detection methods that require direct access to the object is meant by remote sensing the non-contact sensing of the earth's surface, including the Earth's atmosphere. A non-contact observation is, for example, airborne or satellite- borne sensors allows (ie remote sensing sensors such as cameras and scanners). But Chance also come drones and balloons as a platform to use. Associated with the remote sensing photogrammetry and satellite geodesy. In contrast, Planetary Sciences and Astronomy are not associated with the remote sensing, although where remote sensing sensors are used.

In remote sensing, passive or active systems are used, with wide ranges of the electromagnetic spectrum can be evaluated. Passive systems are characterized by the reflected solar radiation on the earth's surface (eg, multispectral ) and the radiation emitted by the Earth's surface characteristic radiation (for example, thermal imaging camera). In contrast, active systems send out microwave or laser beams and receive the reflected components (for example, radar systems and laser altimeter ).

Remote sensing data, especially in the Earth Sciences / Geography of great importance as a global observation of the Earth's surface / atmosphere at high spatial resolution is only possible with the help of remote sensing sensors. In addition to the synoptic overview of large areas of satellite remote sensing sensors also allow a repeated (sometimes daily ) cover the same area.

History

Remote sensing has its origins in the military reconnaissance. From a mostly high point (mountain ) you tried to watch the movements of the enemy. With dawn of aviation, the representation of the perspective changed in a plan view from above. Initially served to still tethered flights with human observers and drawing pad, later aircraft with aerial cameras. The aerial photography could be evaluated relatively early, but the result was always highly dependent on the evaluator. The data now obtained by satellite platforms and various imaging devices and Spektralabtastern can be with computer systems worked and processed (digital image processing). This systematic evaluation has been greatly improved in recent years. Nevertheless, the visual image interpretation remains important even today.

Remote sensing sensors

In remote sensing, find both passive or active systems use, with wide ranges of the electromagnetic spectrum can be evaluated.

The most common sensor types are:

• Multispectral
• Thermal imaging cameras
• Radar systems
• Hyperspectral
• Microwave radiometer
• Laser altimeter
• Interferometer
• Aerial camera

Remote Sensing Satellite (selection)

There are a variety of earth-orbiting satellites. Depending on the task, they are divided into environmental satellites and weather satellites; However, the transitions between the two categories are fluid.

The most important government and commercial Earth observation satellites are

• ( semi- ) government Envisat (ESA, Europe)
• European Remote Sensing Satellite ERS (ESA, Europe)
• Landsat ( NASA, USA )
• SPOT, ( CNES, France)
• IRS ( ISRO, India)
• Earth Observing System (EOS ), (NASA, USA), including Terra and Aqua
• TerraSAR -X (DLR, Germany )

• Commercially HyMap, ( HyVista Corporation, Australia)
• IKONOS ( GeoEye Inc., USA)
• QuickBird ( DigitalGlobe, United States)
• OrbView, ( Orb Image Inc., USA)
• RapidEye ( RapidEye AG, Germany )

A list of Earth observation satellites lists many other satellites. The satellites have listed a wide variety of spectral, spatial, temporal, optical and radiometric resolutions.

Examples of remote sensing instruments are: Airborne Visible InfraRed Imaging Spectrometer ( AVIRIS ) ( airborne system ), Advanced Spaceborne Thermal Emission and Reflection Radiometer ( ASTER ) ( instrument on Terra ), Advanced Very High Resolution Radiometer ( AVHRR ) on the NOAA satellites Thematic Mapper of the Landsat satellite, SCIAMACHY on Envisat, Carnegie Airborne Observatory ( airborne system )

Areas of application

Due to the variety of habitat earth, and the application of modern remote sensing is very broad. The unique opportunity to capture large areas with high temporal and spatial resolution, remote sensing is used in many disciplines.

• Earth Sciences, Geography, Cartography and Geodesy Elevation relief and waterways
• Geology ( rock types, deposits )
• Land cover, land use and land management
• Urbanization ( urban sprawl )
• Forestry ( inventories, estimates of potential wood, forest damage mapping, paths Bauplanungen etc. )
• Agriculture ( crop forecasts, acreage, review of subsidized brownfields, precision farming, etc.)
• Vegetationsphänologie ( aspect episode)

• Forest fires ( extent of damage)
• Volcanic eruptions ( prediction and monitoring)
• Earthquakes ( height change )
• Drought monitoring
• Pollution ( oil spill on the high seas )

• Weather forecast
• Climate monitoring
• Seegangsmessung ( surface waves, currents )

• Trace gases, clouds, aerosols
• Temperature, barometric pressure
• Radiation budget, radiation budget
• Monitoring of emissions, such as carbon dioxide

• Archaeological Flugprospektion
• Mapping of excavations

• Verification of disarmament agreements

• Before-and- after comparison of large-scale destruction

Division and subdivision

By Application

Remote sensing data are used in many geoscientific disciplines apply. According to the remote sensing is further divided.

Breakdown of remote sensing on the application

• Soil Remote Sensing
• Agricultural Remote Sensing
• Botany / vegetation- Remote Sensing
• Forestry Remote Sensing
• Geological Remote Sensing / Geology Photo
• Hydrological Remote Sensing
• Oceanographic Remote Sensing
• Limnological Remote Sensing
• Urban Remote Sensing / town Remote Sensing
• Environmental Remote Sensing ( remote sensing integrated environmental monitoring)
• Climatological / meteorological remote sensing
• Atmospheric Remote Sensing
• Archaeological remote sensing / aerial archeology
• Geodetic Remote Sensing / Satellite Geodesy
• Photogrammetry

On the measuring method

Remote sensing data are collected in various wavelength ranges and with different measurement methods. Accordingly, the remote sensing can be further subdivided.

Breakdown of remote sensing on the measuring method

• Optical Remote Sensing
• Multispectral Remote Sensing
• Hyperspectral Remote Sensing
• Thermal image interpretation
• Passive Microwave Remote Sensing
• Active microwave remote sensing (radar )
• Laser altimetry
• Interferometry ( radar interferometry )
• Luftbildphotografie / aerial photo interpretation
• Photogrammetry and aerial measurement

On the evaluation method

To provide area- differentiated geospatial remote sensing data are processed with different evaluation procedures. Depending on the evaluation of remote sensing can be further subdivided.

Breakdown of remote sensing on the evaluation method

• Remote sensing classification and segmentation
• Remote sensing time series analysis
• Empirical- statistical ( chemometric ) analysis of remote sensing data
• Remote sensing radiative transfer modeling
• Remote sensing model inversion ( inversion of radiative transfer models)
• Assimilation of remote sensing data in process-driven (dynamic ) models
• Remote sensing Entmischungsverfahren
• Remote sensing change detection (English Change detection )
• Image spectroscopy
• Interpretation of aerial photographs and visual interpretation of remote sensing data
• Aerial view measurement and photogrammetric methods ( stereophotogrammetry )

Methods

In the analysis of analog and digital remote sensing data are a variety of methods and procedures for application, which are recorded in note form below. Added to geoscientific work steps associated with the acquisition of reference measurements in the field ( not shown). From the list will clearly shows considerable remote sensing is a methodical science.

• Methods of digital image processing Data processing for visual interpretations ( and Others Stretch Contrast, Saturation )
• Transformation of the color space
• Feature extraction and pattern recognition
• Supervised and unsupervised classification and segmentation method ( inter alia, clustering methods, maximum likelihood classifier, Support Vector Machine, Kohonen )
• Geometric corrections, geometric rectification and rectification
• Radiometric and atmospheric corrections
• Filtering method in the spatial and frequency domains ( inter alia, Fourier analysis )
• Texture Analysis

• Statistical and chemometric methods regression analysis
• Multiple and stepwise multiple regression
• Partial Least Square Regression
• Principal component regression (English Principal Component Regression )
• Discriminant
• Experimental design (English design of experiments )

• Geostatistical methods Interpolation ( inter alia, kriging and co - kriging )

• Method of time series analysis and signal processing trend Analysis
• Change detection / change detection
• Method for filtering of time series ( inter alia, maximum value compositing and Savitzky -Golay filter, splines )

• Learning methods and methods of Artificial Intelligence Artificial neural networks
• Genetic Algorithms
• Optimization methods

• Radiative transfer modeling and mathematical modeling Development of physically based radiative transfer models
• Inversion of radiative transfer models
• Spectral Entmischungsverfahren (English spectral unmixing )
• Sensitivity analysis
• Computer simulation

• Assimilation methods Kalman filter
• Recalibration and Reinitialisierungsverfahren of dynamic process models

• Methods of geoinformatics GIS analyzes ( inter alia, intersections, Buffering, topology analysis)
• Morphological image processing
• Data Mining

• Laboratory and field spectroscopy Spectroscopic measurements

• Method of visual image interpretation picture address
• Texturing Language
• Image interpretation
• Stereo image interpretation

• Photogrammetric methods image measurement
• Stereophotogrammetry

Didactics

In recent times, increasing efforts to integrate into the school curriculum remote sensing. This may be the integration of remote sensing data, such as photographic, digital or microwave-based satellite and aerial images, or remote sensing methods such as resampling, classification of land surfaces and time-series analysis, as teaching aids.