Image Data Purchase and Pre-processing
Litia GaunavouSPC-SOPAC
Pre-Processing
• Image Stitching
• Ortho-Correction
• Haze removal
• Atmospheric correction
• Pan-sharpening
Image Stitching
Stitched Image
Ortho Correction
• Ortho correction requires a DTM• the DTM should have similar scale
as image data
New Satellites: GeoEye-1WorldView-1, WorldView-2
• High geo-accuracy ~ 5m1. Star tracker2. Advanced GPS position
• Ortho Correction required to activate high geo-accuracy
Haze Removal
Raw LandSat 4 TM (Fiji – 1991) Haze Corrected LandSat 4 TM
Atmospheric Correction
- View Angle
- DEM
- Sensor type
- Calibration data
- Sun angle
Corrected Image
Raw ALOS Image (Fiji 2007) ALOS Image + atmospheric correction
IHS Transformation
• Intensity• Hue• Saturation
IHS Transformation and Re-Transformation in ERDAS
Imagine
Red
Green
Blue
Intensity
Hue
Saturation
Red
Green
Blue
Pan-Sharpening
Red
Green
Blue
PanchromaticImage Data
Intensity
Hue
Saturation Saturation
Hue
Normal Bands Pan-sharpened IMG
IHS Resolution Merge
Red
Green
Blue
Resolution increase
Casuarina
Casuarina
Bands: 1, 2, 3, pan-sharpenednatural colour combination
Casuarina
Bands: 2, 3, 4 pan-sharpenedfalse colour infrared
Casuarina
Vegetation Index Bands: 4 – 3 / 4 + 3
Radiometric Resolution
CoastalYellowBlue
Red Edge
GreenNear IR 1
Red Near IR 2
BND 2, 3, 5 Natural C
BND 3, 5, 7 FCIR
BND 3, 5, 6 FCIR RE
BND 3, 5, 8 FCIR (IR2)
Current WV-2 Bundle Data Backdrop Products:
• Pan-sharpened natural colour• Pan-sharpened false colour IR• Pan-sharpened false colour RE• Vegetation index red / near IR• Vegetation index red / RE
Vinaka