ATCOR3: Atmospheric Correction for Rugged Terrain Litia Gaunavou SPC-SOPAC
Feb 24, 2016
ATCOR3: Atmospheric Correction for Rugged Terrain
Litia Gaunavou SPC-SOPAC
Softwarea) Spectra Module
b) Haze Removal
c) Atmospheric and Topographic Correction General
d) Value Adding Products
Haze Removal 1
- Analysing ration near infra-red, blue where the near infra-red is more affected by haze
Masking of image
Raw Landsat Image Clear - Areas/Haze Mask
Haze Removal 2 & 3
- Calculate “clear line” from not affected areas
Haze Removal 4
Raw Landsat TM Image HOT levels
Haze Removal 5
- Changing imageappearance for maskedareas by shifting pixelvalues in relation to “clear line”
Result
Raw LandSat 4 TM (Fiji – 1991) Haze Corrected LandSat 4 TM
Result
Raw ALOS (Fiji 2007) Haze Corrected ALOS
Limitations:
• Needs both clear and hazy areas
• Does remove haze but not clouds
• Does not work over water
• Requires multispectral image data
Spectra Module
Relief, Moisture, Reflectance
EastWest
Atmospheric Correction 3
- Path radiance
- Pixel radiation
- Adjacency radiation
- Terrain radiation
Atmospheric Correction 3 - View Angle
- DEM
- Sensor type
- Calibration data
- Sun angle
Applying ATCOR
View Angle
Different viewangles will be analyzed Differently
DEM
- Most critical parameter in ATCOR3
- Used to calculate the different reliefs
- Used to derive terrain files
Slope
Aspect
Skyview
Shadow
DEM ComponentsGeneration of terrain files
Slope
Aspect
Shadow
Sky view
Artefacts
- Artefacts in the output
data
Calibration data- Stores the band specific radiometric calibration values for each
supported sensor
- Provided by the satellite vendor
Sun Angle- Calculated from the acquisition day and time of the image
ATCOR3 Results
Raw Landsat 4 TM (Fiji 1991) Landsat 4 TM (Fiji) + ATCOR3
ATCOR3 Results
Raw ALOS Image (Fiji 2007) ALOS Image + ATCOR3
ATCOR3 Results
Raw ALOS image
ALOS image + ATCOR3
ATCOR3 Summary• Produces sharp and brilliant satellite
images
• Compares multi-spectral images with similar spectral bands.
• Improves the results of change detection and classification algorithms
Recommendation:• Production of good quality DTMs gain
importance
• Purchase of bundle data gain importance
• SPC-SOPAC conducts atmospheric correction for member countries !
Thank You
Questions?