Difference between revisions of "IKONOS"

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== Pre-Processing Overview ==
 
== Pre-Processing Overview ==
  
Typically, multispectral data are converted into ''Reflectance'' before they are subjected in multispectral analysis techniques (image interpretation, band arithmetic, vegetation indices, matrix transformations, etc.). As with remotely sensed data acquired by other sensors, IKONOS raw image digital numbers (DNs) can be converted to physical quantities such as ''at-sensor Radiance'' or ''Reflectance''. The latter can be differentiated in ''Top of Atmosphere Reflectance'' (ToAR) which does not account for atmospheric effects (absorption or scattering) and in ''Top of Canopy Reflectance'' (ToCR) which introduces a "correction" for atmospheric effects.  
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Typically, multispectral satellite data are converted into physical quantities such as ''Radiance'' or ''Reflectance'' before they are subjected in multispectral analysis techniques (image interpretation, band arithmetic, vegetation indices, matrix transformations, etc.). The latter can be differentiated in ''Top of Atmosphere Reflectance'' (ToAR) which does not account for atmospheric effects (absorption or scattering) and in ''Top of Canopy Reflectance'' (ToCR) which introduces a "correction" for atmospheric effects.
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In order to derive Reflectance values, likewise as with remotely sensed data acquired by other sensors, IKONOS raw image digital numbers (DNs) need to be converted to ''at-sensor Radiance'' values.
  
  

Revision as of 06:50, 26 July 2013

[This page is under construction]

IKONOS is a commercial earth observation satellite. Details about the sensor are provided at Digital Globe's IKONOS Data Sheet

Availability (Sample Data)


Pre-Processing Overview

Typically, multispectral satellite data are converted into physical quantities such as Radiance or Reflectance before they are subjected in multispectral analysis techniques (image interpretation, band arithmetic, vegetation indices, matrix transformations, etc.). The latter can be differentiated in Top of Atmosphere Reflectance (ToAR) which does not account for atmospheric effects (absorption or scattering) and in Top of Canopy Reflectance (ToCR) which introduces a "correction" for atmospheric effects.

In order to derive Reflectance values, likewise as with remotely sensed data acquired by other sensors, IKONOS raw image digital numbers (DNs) need to be converted to at-sensor Radiance values.


Converting to Top of Atmosphere Reflectance, also referred to as Planetary Reflectance, can be done by using the following equation:

Failed to parse (lexing error): \rho_p = \pi * L\lambda * d^2 / ESUN\lambda * cos(θ_S)

where:

  • \rho - Unitless Planetary Reflectance
  • \pi - mathematical constant (3.14159265358)
  • L\lambda spectral Radiance at the sensor's aperture, from equation... ToADD
  • d - Earth-Sun distance in astronomical units, interpolated values
  • Esun - Mean solar exoatmospheric irradiance(s) (W/m2/μm), interpolated values
  • Failed to parse (lexing error): cos(θ_s) - Solar zenith angle, from the image acquisition's metadata

Modules overview

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Pre-Processing

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Importing data

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Color composites

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Pan Sharpening

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Calculate Planetary Reflectance

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References / Sources

See also


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Atmospheric correction

See Atmospheric correction

IKONOS Image classification

See Image classification