4SM shallow water column correction: 
demonstration using a CASI image
from import of raw data all the way to seatruth
Demonstration is now final as of May 2nd 2014


 
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
 




Below are some results of step 13 to 16
using the "PAN solution"
May 17th 2014
54 minutes for the whole demo on my new machine
20 minutes for modeling 32 millions pixels at step_11-1
that's 0.035 ms per pixel,
or 40 times less than the fastest ALLUT process on that same image,
including smart-smoothing and bottom typing,
and with a better precision on retrieved depth

It is fair to stress though
that 4SM cannot account for variable water optical properties
unlike semi-analytical methods

my screen is now FULL HD

TCC

 
FCC

 

Seatruth using the PAN solution
at step 16

the PAN solution is only implemented
deeper than ~3 m
 
Seatruth NOT using the PAN solution
at step 11
for a comparison


 

TCC water column corrected and normalized


 
Classified image


 




4SM on USB3 stick/SSD?
For your Linux guru friend and/or for your system administrator
  • Wouldn't it be nice to have Ubuntu on an external SSD drive/stick
    • together with a working directory for running the demo or tutorials or process any image?
  • So that it may be plugged/booted onto any X86 or AMD64 computer.
  • Note: this would not affect/upset the local IT setup other than assigning one/any particular PC to start/boot from the USB device.
  • This device can be just a USB3 stick like SanDisk Extreme, 32 or 64 GB on a recent PC.
    • Ubuntu needs less than 10GB.
    • The rest is for /home where work can be done.
  • I gather this can achieve record speed at very low cost.
  • Once it works, you can take it around with you
 
  • I should be able to test that, under guidance by your Linux guru friend.
  • OR SO I FIGURE!
  • Please advise whether this is day_dreaming!
  • I figure this could provide a low cost way for me to restrict/control wild dissemination, while encouraging/fostering interest.
    • by providing working fully loaded USB3 sticks, ready for running demo/tutorials
    • by not giving superuser admin priviledges
    • by selling superuser admin priviledges
    • by restricting 4SM to execute on specified USB device identified by its serial number
    • ...