home
scene LC80340432018018LGN00,
January_18th_2018

Data and Deglinting

TOA TCC: raw image
logarithmic enhancement

TOA TCC deglinted image
logarithmic enhancement
Glint regressions using SWIR1

R2 values are fairly high
15 m resampling
 does not increase noise
 
Location of Profile_RED
backdrop is a TCC of deglinted data

Profile_Yellow is also shown
dLsw shapefile is also shown

 

 



Optical calibration for the whole image

Calibration diagram
for the whole image
for bands Blue, Green, Red and NIR

Calibration diagram
for the whole image
for bands Blue, Green, PAN, NIR
CoefKPan=1.00
  • KBLUE/KGREEN~=0.94
    • Jerlov water type Coastal_1
    • nice linear BPL line: denotes homogeneous brightest bottom in homogeneous waters

This calibration suits
the whole image
 
   

Calibration for bands Blue, Green, PAN, NIR
for San Lorenzo Channel , under mask_4
Homogeneous
The SL Channel , under maskSE=4
does not exhibit anything particular
  • 0-25m   water type Coastal_1
    • Kblue/Kgreen~=0.94



Ready for modeling

True Color Composite
of BOAWCC radiances scaled 0-250
B=Coastal band        in channel 34
G=Green  band         in channel 35
R=Blue    band         in channel 36
 

Retrieved depth
see legend
Maximum BOAWCC reflectance (0-1)
for this scene
-RM/0.133/0.175/0.227/0.265/0.315  /0.441/0.425
To convert BOAWCC radiances
into calibrated reflectances
CoastalRefectance=CoastalBOAWCC*0.133/250
BlueRefectance    =    BlueBOAWCC*0.175/250
GreenRefectance  =  GreenBOAWCC*0.227/250
Maximum shallow bottom reflectance (0-1)
for coral sands
-RM/0.310/0.380/0.440/0.550/0.560/0.670/0.700

Coral sand is approx twice brighter
than brightest sands in this scene.

Average bottom brightness
see legend for image B
 
15 m GSD, smart-smoothed
  • not_PANsharpened: sharpening becomes redundant/pointless, thanks to:
    • improved co-registration of the PANchromatic band with the MULTI bands (might still be improved further)
    • combined with 15 m resampling of MULTI bands to match the PANchro GSD
  • smart-smoothing then becomes desirable/necessary



Mid_winter time on January 18th

Computed depth along Profile Yellow
WCC is also shown
for the Coastal, Blue and Green bands

Profile Yellow location
Backdrop is True Color Composite
of BOAWCC radiances scaled 0-250
  • B=Coastal band        in channel 34
  • G=Green  band         in channel 35
  • R=Blue    band         in channel 36

Computed depth along Profile Yellow
compares the Green and the PAN solutions

Z3 vs Z4
GREEN solution versus PAN solution
Dormant
  • dormant: waters and bottom substrates appear to be dormant
  • Reflectance of brightest bottoms unchanged,
    • while most bottoms would be darker than usual in winter
  • dark and dull: such tight correlation of Green vs PAN solutions is only possible provided there is a lack of contrast in bottom substrate spectral signatures
  • Green and PAN solutions yield approx
    the same depth over the whole depth range,
    • except at very shallow depth (<3-4 m).
  • This is mid-winter time
    • in spite of Coastal water type, 
    • calibration is straightforward
? PANsharpening of MULTI bands ?
no obvious benefit; adds some noise
 
  • PANsharpened.............R2=0.97 RMSE=0.56 m
  • NOTsharpened.............R2=0.99 RMSE=0.45 m
 
Over very shallow bottoms
  • GREEN solution yields under-estimated depth over very shallow bottoms
  • PAN solution does not, apparently



 



Créer un site
Créer un site