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BRG GPEM The University of Queensland

• Main page
• Pre-processing
  • Introduction
  • Image acquisition
  • When to correct
  • Correction types
  • Atmospheric correction
  • Relative atmospheric correction
  • Relative atmospheric correction
  • Physics-based correction
  • Bi-directional reflectance correction
  • Bi-directional reflectance correction
  • Geometric corrections
  • When to correct
  • Masking
• Field data collection
  • Introduction
  • Groundcover sampling
  • Field data sources
  • Photo transects
  • DGPS surveys
  • Driving surveys
  • Vegetation structure
  • Using photographs
  • Visual estimates
  • Spectral libraries
  • Example spectra
  • Optical properties
  • Control points
  • Features mapping
• Mapping approaches
  • Introduction
  • Manual delineation
  • Object based analysis
  • Supervised classification
  • Unsupervised classification
  • Inverse modelling
  • Example
  • Regression analysis
• Change and trends
  • Introduction
  • About
  • Image requirements
  • Mapping change
  • Trend detection
  • Example time series
  • Landsat long term
  • Landsat short term
  • MODIS NDVI time series
  • NDVI trends
  • Example change maps
  • Canopy cover
  • River width
  • Land use
  • Foliage cover
  • Vegetation colour
• Delivery
  • Introduction
  • Post classification
  • Refinements and smoothing operations
  • Stratification and post-classification sorting
  • Error assessment
  • Sampling design
  • Sampling unit size
  • Number of samples
  • Sampling scheme
  • Selecting a reference data set
  • Reference data example
  • Derivation of error or contingency matrix
  • Category level accuracy
  • Map level accuracy
  • Quantitative image products
  • Interpreting mapping accuracy
  • Interpreting mapping accuracy
  • Interpreting mapping accuracy
  • Interpreting mapping accuracy
  • Final map creation

"Absolute" correction uses atmospheric conditions and illumination and viewing geometries at the time of image acquisition to estimate the amount of scattering and absorption in each image band, and derives correction factors to re-scale the data from at-sensor to at-surface values.

Absolute atmospheric correction needs access to:

• suitable information on atmospheric conditions across the atmosphere in the imaged area
• radiative transfer code (e.g. Modtran, 6-S)
• software for implementation of correction algorithms in a programming environment (e.g. ENVI-IDL) or automated form (e.g. ENVI FLAASH)

References:

Jensen, JR (2005). Introductory digital image processing: a remote sensing perspective. Third edition, Prentice Hall: 316p.