Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries
WorldView 2 image Marmion Marine Park, Western Australia
June 2nd 2012, 2875*4096, 2 m ground resolution, 5.7 km * 8.2 km,   courtesy of Simon Allen, CSIRO
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Marmion in Simon's image below
Marmion in Perth twin stripes mosaic

This dataset, courtesy of Simon Allen, is comprised of
  • tiles R1C1 and R2C1 12JUN02025339-M2AS_R1C1-052749202010_01_P002 Multi
  • tiles R1C1 and R2C1 12JUN02025339-P2AS_R1C1-052749202010_01_P002 Panchro 0.5 m resolution

Sewage outfall

System noise and pollution


Profile RED
Modeling with bands 1, 2, 3, 5 and 6

  • Dark bottoms represent a rocky platform ~0.5 m
    Here they come out shallower than their brighter surrounding

  • Brighter bottoms exhibit a distinctly green spectral signature

Profile RED
Modeling with bands 1, 2, 3, and 5

  • Here dark bottoms are modeled at ~same depth as brighter surrounding

  • All depths are overestimated in comparison


Sewage outfall

TCC bands 2, 3 and 5
Yellow band is spiked by the pollution

Computed depth


There is severe depth underestimation
 where band 5 is polluted

System noise and pollution

Profile Black
TCC for bands Blue, Green and Yellow

System noise

  • System noise is apparent

    • it is lowest for the 4x4 sum-aggregated Panchro channel

    • it is maximum for the Purple channel

    • starting at 4.5 km, it becomes extreme : what's that?

    • Red band is "rotten"

  • Altogether, this is a noisy image, not suitable for Smart-Smoothing


  • At ~3.85 km, the profile overpasses the sewage outfall

    • Blue, Green, Pan, Yellow and red bands are affected

    • Pollution starts at ~3.1 km in Yellow band

Raw radiances along Profile Black


Nov 23rd 2012


Profile Yellow
The level of radiances is extremely low:
bottoms are very dark
This entails poor performances

Profile Yellow
Computed depth
and water column corrected reflectances
for bands 1, 2 and 3

Computed depth in centimeters

Color composite
of normalized water column corrected bands 1, 2 and 3
histogram equalization enhancement

image WZ

  • Green is mapped to 3: most of this image has bottom detection in only Purple, Blue and Green bands: computed depth is less accurate

  • Yellow is mapped to 5: areas where Purple, Blue, Green and Yellow bands have bottom detection: computed depth should be more accurate (apart from the pollution problem)

  • One may use this image to run separate seatruth regressions

The sewage outfall 
causes depth under-estimation in its surrounding

Threshold at 1.5 on Yellow band is quite low.
And it shows in the image above.
Results might be improved by raising its value.

Nov 23rd 2012
Command Line

4SM -Process    -Origin/SimonAllen                                
-Model/v/runWV2/mask_3    -LL10    @-Tp/2/4               

The PAN band was not used at all
Not worth giving you any of the above :

next see when using the Panchro band
and a proper coverage
of deep water areas and of land areas



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