14 Sep 05 Lecture 3

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EOS 840 - Hyperspectral Imaging Systems
Class Instructors Dr. Richard B.
Gomez rgomez_at_gmu.edu Dr. Ronald G.
Resmini ronald.g.resmini_at_boeing.com
Lecture 3 (14 September 05)
George Mason University School of Computational
Sciences Fall Semester 2005 31 August 7
December
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Contact Information
Ron Resmini v 703-735-3899 ronald.g.resmini_at_boein
g.com (Please put EOS840 in Subject Line) Office
hours by appointment
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Outline

• Review/context/a thread...
• Introduction to radiative transfer theory
• The atmosphere
• Spectral/spatial analysis
• HSI and the ENVI s/w system

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Review/Context/A Thread...

• HSI RS is based on the measurement of a physical
  quantityas a function of wavelength its
  spectroscopy
• HSI is based on discerning/measuring the
  interaction oflight (photons, waves) with matter
• A thread from Maxwells equations to...
• Fresnels equations which describe...
• Interaction of EMR with materials
• Ideal, simple configurations of materials
• Ideal, simple conception of RT processes
• No atmoshpere
• View RT as modeling fluxes or radiometric
  quantities
• We want to describe RS within/through an
  atmosphere of...
• Complicated materials, mixtures, real surfaces
• Complicated interactions of EMR within the RS
  scenario

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Review/Context/A Thread...Why?

• We ultimately want to focus on HSI applications
• Many applications are earth RS through/within the
  atmosphere
• Data are collected by sensor systems
• The data are calibrated (spectrally and
  radiometrically)
• Other corrections/fixes may need to be applied
• Apply atmospheric correction (maybe not all the
  time, though)
• Apply information extraction algorithms
• Spectral libraries
• Apply information and/or data fusion
• Apply geometric processing e.g.,
  orthorectification
• Product generation report writing
• Disseminate, publish, archive
• Plan and conduct future data collection and
  exploitation
• Repeathaving learned more from the process!

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Introduction to Radiative Transfer (RT) Theory

• The RT equation (see next slides)
• Simplified expressions get you gt90 of whatyou
  need to know
• Radiometry and radiation propagation
• Coordinates frames of reference principal
  plane, etc.
• Illumination angle, direction
• View angle, direction
• Phase angle
• Azimuth, relative/absolute
• Its easier if we adopt an earth RS scenario
• But...simplified models are very helpful e.g., a
  layerof gas and/or aerosols isolated in space...

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The Radiative Transfer Equation
Eq. 7.21 on pg. 156 of Hapke (1993).
Arghhhhh!!!!
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On the following
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Some Simplified RT Expressions

• RT can be (and in practice is) viewed as an
  accountingof terms based on radiance
  interactions in the RS scenario
• Bear in mind, however, that there is a link
  between theterms in the accounting and solutions
  to the RT equation
• The accountings can be as simple or as
  complicated asnecessary to address the RS
  question(s)/scenario(s)
• i.e., add terms, delete/ignore terms

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Solar/Reflective RS
For a horizontal surface
Now, add a thermal emission term
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The Big Equation
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The Big Equation (continued)
Theres an LI, too its the adjacency effectand
its sometimes included in the LC term.
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• VNIR/SWIR i.e., solar-reflective
• Thermal infrared i.e., emissive
• More later in the semester
• Status check...where are we?
• See slide Review/Context/A Thread...Why?
• We want to get to r or e
• Getting to reflectance (atmospheric compensation)

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The Atmosphere
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Spectral/Spatial Analysis

• Current approaches
• Really rather immaturespectrally
• Edge-detection
• Texture
• The role of the FFT spatially
• HySPADE (Resmini, 2004)
• Excellent discussion in Landgrebe (2003)
• More to be said with the ENVI s/w system
• Applications
• Strategies...

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HSI and the ENVI Software System