Pansharpening and 8 Spectral Bands of WorldView-2

I was able to develop and test a code in R software using a simple pan sharpening formula (described here ) to create Pansharpened image of WorldView-2 (WV2) Multi-Spectral (MS) bands with high resolution Panchromatic (Pan) band. I have created a gif as shown in the figure above with Pan and MS ( a vegetation composite NIR2 in red, Yellow in green and Coastal in blue) images (data credit: esa).

Pansharpening is a process that merges/fuses high-resolution Pan data with medium-resolution MS data to create a high-resolution MS image (USGS).

WV2 is an imaging satellite of DigitalGlobe Inc., USA (a follow-on to WorldView-1 – WV1). WV2 sensor offers high resolution images in Pan 0.46 cm and unique MS 1.8 m at nadir. The MS bands are listed in the table below (credit: DigitalGlobe):

Band Name Wavelength Detail
Coastal Blue  400 – 450 nm New band
ƒƒAbsorbed by chlorophyll in healthy plants and aids in conducting vegetative analysis
ƒƒLeast absorbed by water, and will be very useful in bathymetric studies
ƒƒSubstantially influenced by atmospheric scattering and has the potential to improve atmospheric correction techniques
Blue 450 – 510 nm Identical to QuickBird
ƒƒReadily absorbed by chlorophyll in plants
ƒƒProvides good penetration of water
ƒƒLess affected by atmospheric scattering and absorption compared to the Coastal Blue band
Green 510 – 580 nm Narrower than the green band on QuickBird
ƒƒAble to focus more precisely on the peak reflectance of healthy vegetation
ƒƒIdeal for calculating plant vigor
ƒƒVery helpful in discriminating between types of plant material when used in conjunction with the Yellow band
Yellow 585 – 625 nm New band
ƒƒVery important for feature classification
ƒƒDetects the “yellowness” of particular vegetation, both on land and in the water
Red 630 – 690 nm ƒNarrower than the red band on QuickBird and shifted to longer wavelengths
ƒƒBetter focused on the absorption of red light by chlorophyll in healthy plant materials
ƒƒOne of the most important bands for vegetation discrimination
ƒƒVery useful in classifying bare soils, roads, and geological features
Red-Edge 705 – 745 nm New band
ƒƒCentered strategically at the onset of the high reflectivity portion of vegetation response
ƒƒVery valuable in measuring plant health and aiding in the classification of vegetation
NIR1 770 – 895 nm Narrower than the NIR1 band on QuickBird to provide more separation between it and the Red-Edge sensor
ƒƒVery effective for the estimation of moisture content and plant biomass
ƒƒEffectively separates water bodies from vegetation, identifies types of vegetation and also discriminates between soil types
NIR2 860 – 1040 nm New band
ƒƒOverlaps the NIR1 band but is less affected by atmospheric influence
ƒƒEnables broader vegetation analysis and biomass studies

I have also created a gif as shown in the figure above with Pan and MS ( a shadow composite NIR2 in red, Red Edge in green and Yellow in blue) images to compare results.

Panchromatic Band
Composite NIR2, Yellow and Blue (Before Pansharpening)
Composite NIR2, Yellow and Blue (After Pansharpening)

 

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