Syntax_Calibrate
Specify the model calibration diagram

back to Help


 
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
 
Syntax calibrate
Howto Calibrate
Beware
  • For Calibration, the -extract argument must be accessible: lowercase -e
  • Beware that the adequate -extract... argument must be read first, so that
    • 4SM reads the proper textfile for calibration data
    • or extracts a proper textfile
  • If no -extract... argument has been read, then 4SM shall not proceed!
Please refer to
 tarawa-subset-calibrate

-Calibrate/voAI/BdsNpzG/bDh_12_13  
-Calibrate/voAI/BdSNpZG/BC_8_5_3_2/BDh_12_13_34

 

 

 
  • -Calibrate/v/BdSNpZg/BDh_12_13
    • abridged version for a GRN image, all other parameters are read from textfile 4sm.def
  • -Calibrate/v/BdSNpZg/BDh_12_13_34
    • abridged version for a BGRN image, all other parameters are read from textfile 4sm.def
  • Verbose        -Calibrate/VOAI/...
    • V...............Verbose mode             v................silent mode
    • O..............Optimizerflag=1         o................Optimizerflag=0
    • A...............CalibrateAll=1           a................CalibrateAll=0
    • I................Plot Isobath lines        i................IsoB=0
  • CodePS         .../BdSNpZg/...
    • B(b).........to plot (or not) the Brightest_Pixels_Line with stars
    • D(d).........to plot (or not) the Darkest_Pixels_Line with crosses
    • S(s)..........to plot (or not) the Soil_Line with circles
      • if above S is enabled
        • M.........to select SOIL_Line using mSOIL
        • D.........to select SOIL_Line using average DPL
        • N.........to select SOIL_Line using Red/Nir and CSL
        • 1...........to select SOIL_Line using Z=0.1 in imageZ
    • P(p)................to plot (or not) all mSOIL_Pixel_Soil with points (obsolete)
    • Z(z)................to plot (or not)ZC, ZCRLM, ZAvShallow
    • G(g)............... to plot (or not) ghost pixels
  • Bands to calibrate
    • SPOT and Landsat TM and ETM:
      • not needed for a GRN or BGRN image
    • All images with more than 4 bands:
      • four wavebands at most may be specified
      • for a N-bands image, four wavebands MUST be specified,
      • like   ..../16_12_9_1/....     in order of decreasing wavelength please
  • BiDimensional               ........../BDh_12_13_34...........             
    • B(b)................histograms to be plotted (or not)
      • B...........to plot bidim histograms
      • b............to NOT plot bidim histograms
    • D(d)
      • D............to plot Bidim histogram as a backdrop of model lines
      • d.............to plot ONLY a bare bidim histogram
    • H(h) a choice of Brighter or Darker BiDim rendering
      • H.........for a brighter BiDim rendering
      • h.........for a darker BiDim rendering
    • Choice of 2 or 3 pairs of bands
      • for a 3-bands image:  either 12_13 or 12_23
      • for a 4 bands image: add either _14 or_ 24 or_34
      • for a N-bands image,  the number of combinations is more plentyfull








 
CALIBRATION : Iteration on bands to process
  • for a 3  bands image, all 3 bands are processed at once: -Calibrate/V/BdSMpZ/BDh_12_23
  • for a 4  bands image, all 4 bands are processed at once: -Calibrate/v/BdSNpZ/BDH12_23_34
  • for a N bands image, only 4 bands are processed at once,
    • like -Calibratev/BdSnpZ/16_12_9_1/BDH12_23_34, 
    • and the practitioner shall iterate on band combinations until all wavebands are correctly calibrated.

Automatic ReStart loop
  • After alterations in the command line, and upon termination of the display,
    • the calibration command line is automatically executed again, etc,
    • until the practitioner is eventually satisfied
      • and kills the process manually on the session screen: "CTRL C".
    • Loop: by closing the display, the calibration.sh  script goes on to run the command line again
      •  see at the end of this script: you may disable the last line "#./tarawa-subset.sh"
  • This requires though that the shell script be named by the name of the PCI database with a .sh suffix, like tarawa-subset.sh here for database tarawa-subset.pix
  • Beware though that this automatic restart procedure causes several 4SM process to remain sleeping:
    • see System Monitor
    • 4SM now kills them automatically before modeling, in order to free resources

 
 


CALIBRATION PLOT OPTIONS

 -Calibratev/ B(b)D(d)S(s)MP(p)Z(z)G(g) / B(b)DH(h)...     

 

BPL
Options for plotting the Brightest Pixels Line

 
  • -Calibrate/V/bDSMPZG/.........
  • -Calibrate/V/BDSMPZG/.................
    • uppercase B
    • enable the plot of the BPL pixels
       
DPL
Options for plotting the Darkest Pixels Line
  • -Calibrate/V/bdSMPZ/.........
    • lowercase d
    • disable the plot of the DPL pixels
  • -Calibrate/V/bDSMPZ/.........
    • uppercase D
    • enable the plot of the DPL pixels       caloption_DPL_on
    • most DPL pixels are at extremely shallow depth: therefore, when no clear soil line may be obtained, the DPL, or at least part of it, may sometimes be used as a substitute for the Soil Line: the area where mSE=2 is too small with few dark pixels at very shallow depth; therefore the illustration caloption_DPL_on  was made after extracting using mBPL_1 in the -Extract argument -extractv/3Max255/mBPL_1/mSOIL_21 (see below).
SL
Options for plotting the Soils Line
  • -Calibrate/V/bDsMPZG/.........
    • lowercase s
    • disable the plot of the SL pixels           caloption SLoff
  • -Calibrate/V/bDSMPZG/.........
    • uppercase S, uppercase M
    • specify SoilLine by mSOIL                   caloption SL by mSOIL
  • -Calibrate/V/bDSNPZG/.........
    • uppercase S, uppercase N                 caloption SL_by NIR
    • specify SoilLine by NIR
  • -Calibrate/V/bDSDPZG/.........
    • uppercase S, uppercase D                  caloption_SL_by_avDPL
    • specify SoilLine by DPL
      • most DPL pixels are at extremely shallow depth:
      • therefore, when no clear soil line may be obtained,
      • the DPL, or at least part of it, may sometimes be used as a substitute for the Soil Line:
      • the area where mSE=2 is too small with few dark pixels at very shallow depth;
      • therefore the illustration caloption_SL_by_avDPL was obtained after extracting using mBPL_1 in -extractv/3Max255/mBPL_1/mSOIL_21 (see below).

Z
Option for plotting the Zi vs Zj inserts
 
  • -Calibrate/V/bDSMPzG/........
    • lowercase z to disable the plot of Z2_vs_Z3
    • -Calibratev/BdSMpz/3_2_1/bDH_12_23                caloption Z off
  • -Calibrate/V/bDSMPZG/.........
    • uppercase Z to enable the plot of Z2_vs_Z3
    • -Calibratev/BdSMpZ/3_2_1/bDH_12_23               caloption Z on would have ZZ inserts
 
G
Option for plotting the Ghost pixels
-Calibrate/V/bDSMPZG/.........      to plot the ghost pixels
-Calibrate/V/bDSMPZg/.........        to disable the ghost pixels

 
B(b)DH(h)
Options for ploting the BiDimensional Histograms
  • uppercase B ...............enable the plot of BiDim histograms:
    • -Calibrate/v/BdSMpZ/3_2_1/BDH_12_23
    • -Calibrate/v/BdSMpZ/3_2_1/bDH_12_23
      • shall not plot the bidimensional histograms    caloption_BDH_off
    • -Calibrate/v/BdSMpz/3_2_1/bDH_12_23
    • shall plot neither ZZ inserts nor the bidimensional histograms
  • lowercase h ............. you can get a darker shade of grays rendering of the BiDim histogram
    • -CalibrateV/BdSNpZ/3_2_1/BDH_12_13 ................my prefere
    • -CalibrateV/BdSNpZ/3_2_1/BDh_12_13 ................shades of grays are too plale
/3_2_1/
/4_3_2_1/
/12_7_4_1/
The choice of bands to calibrate
The calibration process can only process 3 or 4 bands at a time
  • /3_2_1/ ............in Spot images, only 3 bands are available by default
  • /4_3_2_1/ ........in Landsat TM/ETM or Ikonos images, 4 bands are available by default
  • /12_7_4_1/ ......in hyperspectral images, Landsat 8, WorldView, etc, 4 bands must be specified at a time for calibration