Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passivremote sensing imageries
  
WorldView 2 image Waimanalo Beach, Oahu, Hawaii islands
July 2011, 9721*9721, 2 m ground resolution, 19.4 km * 19.4 km,   courtesy of Ron Abileah
 
[back to Oahu]

This is image_3
of a series of 7 taken same day

e remote sensing imageries
 


 
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
 
work done Oct 4th 2012
 

ZComputed

ZComputed - ZRecorded
Blue denotes underestimation
Red denotes overestimation

Seatruth regression for the whole dataset


 

Profile black

 
ZZRegressor: Statistics of seatruth ZC-ZR
on image waimanalowv3 at Oahu, Hawaii
N=5.681 millions pixels -E1900/5800/4500/7800
HTide=0.00 Smooth=1_5 Using_bands_1_2_3_4 cZ=1.00
 5.76% pixels with depth underestimated by more than 5.0 m
 6.66% pixels with depth underestimated by more than 3.0 m
 7.24% pixels with depth underestimated by more than 2.0 m
12.24% pixels with depth underestimated by more than 1.0 m
23.48% pixels with depth underestimated by more than 0.0 m
34.88% pixels with depth  overestimated by less than 1.0 m
 7.56% pixels with depth  overestimated by less than 2.0 m
 1.33% pixels with depth  overestimated by less than 3.0 m
 0.65% pixels with depth  overestimated by less than 5.0 m
 0.21% pixels with depth  overestimated by more than 5.0 m

58.36% of computed depths are within  +-1.0 m of DTM depth
78.16% of computed depths are within  +-2.0 m of DTM depth
86.73% of computed depths are within  +-3.0 m of DTM depth
94.03% of computed depths are within  +-5.0 m of DTM depth
over a total of 100.00% of computed depths


 

ZComputed is used for water column correction
TCC bands 2, 3 and 4

This water column corrected TCC view
is a "low-tide view"
 
LB = Lsw + (Ls-Lsw)*exp(2K * ZComputed)
4SM depth is used in this computation
 
  • "polluted areas" do not show that much here in comparison
  • no wonder:
    • estimated not-tide-corrected estimated 4SM depths
    • have been applied
    • instead of true measured tide-corrected SHOALS depths
  • ?still: the "polluted area" looks dull



 
Oct 3rd 2012
nice -20  4SM.4.09  -Process  -Origin/Abileah           
-DB/waimanalowv3/47_3_16_0/8_51/9721_9721/644.132_2333.8625/1_1   
-Mis/Hawaii/Oahu/WV02/Multi/TIF/UTM_30_008/0.002_0.002/01_JUL_2012   
-LS/05000.0/5000.0/5000.0/5000.0/5000.0/5000.0/5000.0/5000.0       
-cWL/0.500/0.500/0.500/0.300/0.500/0.500/0.500/0.500_AutoCAL       
-M/@0000001/@0002/00003/00004/@005/@006/@0007/00008           
-LsM/135.9/140.3/149.7/165.3/166.9/168.1/148.6/147.5_cLM=0.700   
-Lsw/80.62/52.20/28.58/20.36/14.87/12.32/08.19/07.54           
-Lw/0006.6/005.0/003.0/002.0/001.0/000.0/000.0/000.0            
-Lm/0001.0/001.0/000.5/005.0/005.0/005.0/255.0/255.0           
-Veg/073.3/048.2/033.6/022.9/016.7/057.9/110.5/114.1           
-SCL/00110/00087/00134/00153/00083/00149/00100/00147            
-KK2_3_0.3800/Knir8.900/mask_3WaimanaloOIwatertype           
-Z/lAT0.50/runWV2/n_2/mask_3                       
-B/TclNe/cLM1 .5 .5     -nDR_50_ZDTM                   
-deglint/VRbaD/DegTol1.00/F1/L8/N1/FN/mDEGLINT1/GlintM500       
-extract/v/mapBPL/rawBDH/NIRband8/NIRmax5.0/FullBDH/mSOIL21/mBPL2/Ext_1_9721_2600_7800        
-calibrate/v/BDSNpzg/BC_8_6_5_2/BDh_12_13_24               
-Model/v/runWV2/mask_3    -LL100                       
-Smooth/5/D/smart+                                                                      
@-ProfileAB/Z/profile_black/chAB_1_2_3_4                            
-RegressZZ/v/p/DTM_10/0.001_0_0/1.000_0.0/ZR/3_4/0_201/0_50_50/* -E1900/5800/4500/7800