Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries

CASI image of Gezirat Siyul Reef, Red Sea
Work updated in 2006
return to 4SM Study Cases
Image courtesy of HDI . This is a 12 bands image, 2800 x 5900, pixel resolution 1 meter.

Bandset : -WL410/430/451/470/490/509/523/538/550/565/608/850 in nanometers

Unfortunately, this dataset lacks bands in the red and green region of the solar spectrum.

Glint parameters appear to change in a subtle way from start to end of data collection.
And the mosaic includes oblique viewing which fades out at some locations.

A very good dataset anyway: lots of photons!

see CASI presentation for U. of Hawai in year 2000 (6 MB)

calibration
deglinting
bottom profile
bottom typing

Work below was done in 2000, then may 2008




Bottom typing: 32 types are mapped by 4SM White: 4% of shallow pixels are UnClassified review the statistics of bottom typing see the location of training sites see modal filtered image: -Classify_4_0F/Mode_2_19_24	Bottom typing legend Clearly, bottom types should be re-numbered and possibly binned into less super bottom types review How To Classify
before filtering -Classify_4_0F/mode_2_19_24 Bottom typing details	after filtering see a slightly modal filtered image: WinRadMod=2 -Classify_4_0F/Mode_2_19_24 A wider filter window (WinRadMod up to 5) would wipe out many small coral growths

Calibration diagrams
(2015)

Optical calibration diagram for the whole reef for 490, 550, 608 and 850 nm Water type is ~OIB+0.3 of Jerlov	Optical calibration diagram for the whole reef for 451, 565, 608 and 850 nm Water type is ~OIB+0.3 of Jerlov
Optical calibration diagram for the reef lagoon only for 490, 550, 608 and 850 nm Water type is the same See that water depth is limited to ~10 m