HICO at Key Largo, Florida
keylargohico_20091113

work done in april 2015

return to HICO



refer to other 4SM work using ETM, ALI and Hyperion over Florida Keys

Please refer to "Bathymetry of shallow coastal regions derived from space-borne hyperspectral sensor" Lee et al, 2006    a449228.pdf
Please refer to "11_Ocean_Products_Using_a_Look-Up-Table_Approach_22FEB11_Bowles.pdf"
 
This is a complete failure
  • atmosphere is extremely complex, deglinting does a poor job
  • water optical properties are most variable over the scene
  • polarization of HICO radiances might come into play


 
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
 




 

The data
TCC deglinted
Note the areas of confined waters
TCC deglinted
logarithmic enhancement
"deglinting" does a poor job!


 
FCC deglinted
logarithmic enhancement
PAN deglinted
logarithmic enhancement



Deglinting along Profile White
based on the cloudy area


Deglinting along Profile White
for NIR, Red, Green and Blue bands

Note: poor deglinting :
the atmosphere is far from homogeneous
Bowles et al signal
polarization of HICO radiances

Estimation of deep water radiances
is most uncertain:

see the deglinted red band

Location od Profile White


Optical calibration for the whole image
all parameters under good control
they depict properties of the clearest waters in the entire image

Calibration diagram
for the entire image
for bands
NIR_28, Red_22, Green_13 and Blue_7

Calibration diagram
for the entire image
for bands
PAN_27, 20, 10 and Blue_7


Profile Red

Profile Red
shows retrieved depth
and water column corrected radiance
PAN solution, NO SMOOTHING
 
Profile Red location
 




Retrieved depth
  • modeling uses the "PAN solution" for all pixels
  • no smoothing applied, thanks to good signal/noise
  • deglinting based on NIR band does not achieve correct "cleaning" of the atmosphere of this scene
  • water optical properties are most variable in this scene, under the influence of the Everglades, and of human activities
At this stage, it would appear that LUT does no better
than 4SM for this very complex scene

from Bowles et al, feb 22nd 2011
HICO-4SM output
4SM retrieved depth
VERY BAD