Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries
Busy? 4SM in 10 lines        
4SM illustrated: thematic and geographical

VNC : let's work together live!
4SM errors
4SM conclusions

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
I keep digging
until suitable data
become available

the image

a mask

Calibration data

 Optical calibration

  The 4SM

a mosaic


Smart Smoothing

of the data

 Sea truth

 Water Column

Bottom Signature

 Bottom typing
Princess Cays

Heron Island

 Computed Depth

 Contour Map
3D diagram

Deal or NoDeal?


  • It shall be seen that an acceptable calibration which yields acceptable results
    • is a fuzzy concept in respect of the many parameters involved
    • even though we are using a simplified radiative transfer model
  • What is important is NOT
    • that a physically exact calibration has been achieved
    • leave that for the big boys at NRL
  • Rather what is important to US
    • is that a coherent set of calibration parameters be assembled
    • so that an acceptable and useful result be produced : DTM and bottom type classification
    • using only the image
  • 4SM offers an integrated set of ergonomic tools to achieve that
    • within a short time frame

Busy? 4SM in 10 lines

Where is the competition?

4SM thematic illustrations : from raw data to final output


4SM geographic illustrations : just some of the images processed


SPOT XS : in excess of 50 images!

Moorea, French Polynesia Bora Bora, French Polynesia


tmnov tutorial
Alacranes atoll, Gulf of Mexico Davies reef, Great Barier Reef
Lee Stocking Island, bahamas Gubal Straight, Red Sea

Sabah, Borneo
 Rangiroa atoll, French Polynesia  Negril, Jamaica Chinchorro, Caribbean Scott Reef, Western Australia
 Herin Island, Great barrier Reef      


Lee Stocking Island, Bahamas Dubai