Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries
The 4SM Command Line is an executable script 

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  • MakePIX: to create a PCIDSK formated image
  • Import: to import raw data
  • MakeLand: to segment the dry land in the image
  • Recode: to segment the image into deep waters, shallow waters, clouds, etc

to run either of the following processes

  • Scale 16-bits data into 8-bits data, write out a scaled image
  • Delimb remove limb brightening from raw CASI flightlines
  • Fill occasional No_Data pixels through a smoothing process, and write a "filled" spectral image, either 16-bits or 8-bits
  • Linearize linearize the data and write out a "linearized" 8-bits spectral image.

to deglint the image

  • 2: a deglint tolerance threshold
  • 3_14: deglinting is based on channel_3
    • only pixels with Ls3<=14 shall be deglinted
  • FN...: deglinting may be restricted to a selection of flight lines in a mosaic
  • 1_255: controls the deglint parameters training sites
  • 570_640_200_400: a rectangular area where glint calibration parameters shall be estimated
  • also writes a linearized image

to extract image data for the purpose of optical calibration


  • U8 data is 8-bits unsigned radiance.
  • 3max255
    • 3max255 shall accept all pixels for the BPL.
    • 3max5 would restrict extraction of BPL data to pixels which read less than Lsw[3]+5 in band 3. This feature excludes heavily glinted pixels from the calibration textfile, so that the BPL appears more clearly.
  • mBPL
    • mBPL_1 only accept pixels masked under the 1-20 code range in mask mSE.
    • mBPL_2 only accept pixels masked under the 2-20 code range in mask mSE: this is how pixels masked at 1 are excluded.
  • mSOIL_21 only accept pixels masked at 21 to make out the Soils Line.
  • mSHAL
  • M(m)ask_2 in the -model argument:
    • only accept pixels masked under the 2-20 code range in mask mSE: this is how pixels masked at 1 are excluded. This overwrites the mBPL variable.
    • same as mBPL2, but writes a calibration textfile image_m2.cal instead of image_m0.cal

to run the Calibrator module

  • BdSMpZ a syntax to take control on what is going to be plotted
  • 3_2_1 to specify which bands are to be calibrated.
  • BDH_12_23 to plot the bidimensional histograms of shallow water pixels examined for extraction of the BPL. Scatterplots of band 1 vs 2 and of band 2 vs 3 are specified here.
  • bDH_12_23 would disable the BiDim Histogram tool.

To run the Modeler module

  • Smooth_4d/Smart_1+ :shall smooth the shallow pixels through a "smart-smoothing" scheme, i.e. an "edge-preserving" process.
    • Deep water pixels shall NOT be smoothed (saves time).
    •  + or -, to enable/disable smart-smoothing of bright pixels.
  • Smooth_4D/smart_1+ :shall smooth the shallow pixels through a plain smoothing with a smoothing window radius of 4.
    • Deep water pixels shall be smoothed as well.
  • mask_2: mask mSE shall NOT be used to restrict area to be processed.
  • Mask_2: mask mSE shall be used to process ONLY pixels under mSE==2, while other shallow pixels are simply duplicated from previous processing.
The command line
for a 17 bands CASI dataset
It is getting quite involved. 
Law and order are required.

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