Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using
World View 2 at Lee Stocking Island, Bahamas
the "PAN solution" uses the PANCHRO band
bands 1, 2, 3, Panchro, 4, 5, 6, 7 and 8
become
bands 1, 2, 3, 4, 5, 6, 7, 8 and 9

For other 4SM investigations using the panchromatic band:
see my PANCHROMATIC web page


home


 
1 - NO NEED for field data, nor for atmospheric correction
2 - this is demonstrated in this website, using a variety of hyper/multi spectral data
 
Requirements are
1 - homogeneous water body and atmosphere
2 - some coverage of optically deep water
3 - some coverage of dry land
 
Problems are
1 - the precision on estimated depth is found wanting, because the noise-equivalent change in radiance  of accessible data is too high for shallow water column correction work 
2 - radiance data should be preprocessed by the provider at level 1 in order to improve S/N ratio
3 - exponential decay: the deeper/darker the bottom, the poorer the performances
 
So
I keep digging
until suitable data
become available
 

Modeling

All modeling was performed using the "PAN solution".
This means: Purple, Blue and Green bands against PANchro band.
This means: Yellow, Red, RedEdge, NIR1 and NIR2 play no role in modeling.

Retrieved depth

Bottom brightness in the blue band

TCC zoom, TOA

TCC zoom, water column corrected, TOA

NDR, zoom
NormalizedDifferenceRatio=(LB1-LB3)/(LB1+LB3)
  • negative values are mapped in shades of green
  • positive values are mapped in shades of purple

TCC zoom, water column corrected, normalized
  • enhances dramatically the subtle nuances of the above water column corrected TCC
  • the spectral contrast is enhanced, irrespective of the brightness


Results by Mobley et al, 2005
using Ocean PHILLS image
  • The profile shows that the oolithic ridge is ~6 m high, from 3 m at the top  to 9 m at the base
 





 

Profile Orange









Profile Red
  • The oolithic ridge is located between waypoints 1 and 2 in all four sections.
    • its spectral water column corrected signature is high in the Purple channel
  • The profile shows that the oolithic ridge is ~6 m high, from 5 m at the top  to 11 m at the base
  • Please note the 15-20 m deep through in Profile_Red between waypoints A2 and A3, with an extremely green bottom signature.

Profile Black
  • Please note that the water column corrected reflectances have been divided by 2 in order to accomodate the very bright reflectances at the end of Profile_black (section A2)
 
System noise
  • these profiles are very noisy, in spite of strong smart-smoothing.
    • this noise is seen to increase steadily from shallow to deeper (much more than with a "Green" solution).
    • this comes with the "PAN solution", and reduces the "precision" on retrieved depths.
The advantage of the "PAN" solution
  • In 4SM, and in the absence of a PAN channel,
    • first the "RED solution" is operated for pixels that carry a Red signal that is stronger than the Red threshold value.
    • then the "YELLOW solution" is operated for pixels that carry a Yellow signal that is stronger than the Yellow threshold value.
    • then the "GREEN solution" is operated for pixels that carry a Green signal that is stronger than the Green threshold value.
  • This means that gaps show off atboth transitons
    •  Red_to_Yellow
    • Yellow_to_Green
  • Using the "PAN solution" for all pixels yields a depth raster without any gap, much to the relief of the end-user!
 



 
  • Georeferencing: this image in a geographic projection (Lat/Long):
    • see details in 09DEC07154605-M2AS-052963315020_01_P001.IMD in zipfile
    • UL origin is -76.232682 and 23.871708, as reported by OpenEV for tile R1C1
    • pixel size are 1.7999999948e-05 and 1.80000000012e-05, as reported by OpenEV for tile R1C1
This zipfile contains the following:
  • lsiwvmp_20091209_Zcm.tif  one S16 channel, retrieved depth in centimeters, as is: uncorrected for tide
  • lsiwvmp_20091209_WCC.tif seven U8 channels, TOA water column corrected reflectances, scaled 0-250
    • channels 1 to 6 are water column corrected Purple, Blue, Green, PAN, Yellow and Red
    • channel 7 maps the "solution":
      • 4 for the "PAN solution",
      • a very few 3 for the "Green solution" where the PAN signal is less than the threshold.
  • 09DEC07154605-M2AS-052963315020_01_P001.IMD
  • 09DEC07154605-M2AS-052963315020_01_P001_README.TXT
  • BASE.TXT

Please,
can someone knowledgeable run this result through seatruth validation?

as I have no access to seatruth data.

 
 







Command line
Oct 30th 2013
#nice -20  4SM -Process    -Origin/DigitalGlobe                               
-dB/lsiwvmp_2009_12_09/50_3s_9S_0s/9_54/9178_8864/0.0009_15.9543/1_1                   
-dB/lsiwvmp_20091209_Zcm/0000_1s_0S_0s/1_1/09178_8864/0.0009_15.9543/1_1                   
-dB/lsiwvmp_20091209_WCC/0007_0s_0S_0s/1_1/09178_8864/0.0009_15.9543/1_1                   
-Mis/Bahamas/LeeStockingIsland/WV02/MultiPan/PIX/UTM_18_008/0.0018_0.0018/09_DEC_2009           
-MakePIX            @-Prepare/Scale                               
-WL/0427.0/477.5/546.0/570.0/597.8/644.0/724.0/831.0/908.0                       
@Import/data*lsiwvmp_20091209/dbnc_0_0s_9S_0s/R9178_L8864/Origin_0000_15.9552_0_0/chIn1,9/chOut54,62
-LS/005000/05000/05000/05000/05000/05000/05000/05000/05000                       
-M/@000001/@0002/00003/00004/00005/00006/00007/00008/00009                       
-SCL/00066/00115/00179/00169/00132/00091/00122/00107/00083                       
-extract/v/rawBDH/fullBDH/NIRband9/NIRmax5.0/mBPL3                           
@deglint/VRbaD/q/DegTol1.00/F1/L9/N1/FN/mDEGLINT1/GlintM25                       
-AutoCAL/print_2_3/mapBPL/MakeNewMask/GetGlint/GlintM25.0/clouds                   

nice -20  4SM   -Process  -Origin/DigitalGlobe                       
-dB/lsiwvmp_2009_12_09/50_3s_9S_0s/9_54/9178_8864/0.0009_15.9543/1_1           
-Mis/Bahamas/LeeStockingIsland/WV02/MultiPan/PIX/UTM_18_008/0.0018_0.0018/09_DEC_2009   
-LS/05000.0/5000.0/5000.0/5000.0/5000.0/5000.0/5000.0/5000.0/5000.0           
@WLM/453.0/508.0/581.0/575.0/627.0/689.0/744.0/890.0/954.0               
@WL/0427.0/477.5/546.1/570.0/607.5/679.0/724.0/831.0/908.0               
@WL/0427.0/477.5/546.0/570.0/593.9/629.9/724.0/831.0/908.0               
-cWL/00.50/00.50/00.50/00.50/00.15/00.20/00.50/00.50/00.50               
@CP/0216.5/208.8/163.6/076.2/063.6/027.0/011.0/006.3/005.8_4.00m           
@LsM/295.1/287.7/284.5/280.4/275.9/277.7/266.8/261.6/287.7               
-LsM/398.5/400.2/410.6/411.2/405.0/409.4/394.8/389.2/428.7_cLM=1.500           
-Lsw/118.2/074.8/037.3/025.7/020.2/014.4/010.8/006.3/005.8               
-dLsw0-1.0/000.0/000.0/000.0/0-0.0/0-0.0/000.0/000.0/000.0               
-Lw/0030.0/012.0/005.0/000.0/002.5/000.0/000.0/000.0/000.0               
-SCL/00066/00115/00179/00169/00132/00091/00122/00107/00083               
-Lm/0001.0/001.0/002.0/000.3/003.0/003.0/001.0/255.0/255.0               
-M/@000001/@0002/00003/00004/@0005/@0006/@0007/@0008/00009               
-KK2_3_0.730/Knir16.000/Bm400_BG510_GR600_RN700/mask_3           
-Z/MSL0.00d/cSL1.18/N_2/NDR_53_2000_zDTM/mask_3               
-B/TclNe/cNorm5.00/cLM2 0.66666 1 .5                   
-deglint/vRbaD/q/GlintM100.0                       
-extract/v/rawBDH/fullBDH/NIRband9/NIRmax5.0/mBPL3/mask_3       
-calibrate/v/BdsMpZG/plot_BPL/BC_6_5_4_2/BDh_12_13_14           
-Model/v/runWV2/mask_3    -TPs/2/4/Text     -LL10           
-Smooth/5/D/Smart+                            
-ProfileAB/ZrvWB/profile_black/dTM/chAB_1_2_3 _5_6