| 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 usefull result be produced : DTM and bottom type classification
- using only the image
- 4SM offers an integrated set of ergonomic tools to achieve that
- withing a short time frame
|
|
4SM value
Can you afford to wait for a few decades,
untill the semi-analytical methods come of age?
- The value of 4SM is not so much in outstanding concepts
- which are described if full detail in this website
- which are fully demonstrated to be safe to use
- subject to radiometric quality
- subject to narrow wavebands
- subject to homogeneous atmosphere and waters
- provided the deep water radiance may be estimated from the image
- Rather it stems from the variety and large number of images processed starting 1994
- which confers to 4SM its "operational and practical" character for commercial operation
- subject to re-writing of the code by a professional programmer
|
|
4SM KEY FEATURES
What's new with 4SM?
|
- data: read the 8 or 16 bits raw imagery, up to 20 spectral bands at present,
- glint: remove the sun/skyglint, and the adjacency effect as well to a certain extent, from this raw data,
- calibration: extract all the necessary calibration information, and processes it to derive all necessary calibration parameters,
- model: model all shallow water pixels,
- output: write out various outputs.
- smoothing: apply a smart smoothing to shallow water pixels,
- subwindow: any sub-area (rectangular) or sub-zone (mask) may be processed.
- on the fly: 16>8 bits scaling, mosaic equalization, removal of glint, and smart-smoothing, and modelisation are performed on the fly.
- The bash commandline . 4SM reads the raw data and applies the whole suite of procedures "on the fly"
|
- File Structure: PCI Geomatica Band-Interleaved, or File-Interleaved for very large images.
- Mask : the practitioner interactively prepares a Special_Effects_Mask.
- License : upon modeling, 4SM checks for Licensed_Image. If applicable, issue a LicenseKey and quit
- The bash commandline . 4SM reads the raw data and applies the whole suite of procedures "on the fly"
- from raw data in all cases all the way to writing final output:
- see tmnov.sh for a 4-bands spectral image,
- see mb4.sh for a 17-bands hyperspectral image
- Scale 16 bits data into 8 bits data for purpose of display only (CASI, Ikonos, ...).
- RAW DATA : all computations are conducted on raw original data, in real variables, so that none of its dynamic is lost in the process.
- Extract calibration data: Brightest_Pixels_Line and Soil_Line, etc tmnov_m0.cal
- Calibrate modeling parameters: calibration using GMT for graphic display tarawa-subset_1_2_3.eps
- Writes
- an 8-bits image_WZ: make a note of modeling conditions tmnov_WZ
- an 8-bits image_WR: make a note of smart-smoothing window radius tmnov_WR
- an 8-bits image_Z250: depth from 0 up to 250 decimeters tmnov_Z250
- an 8-bits image_B: average bottom reflectance in the range 0-200 tmnov_B
- an 8-bits image of the depth range entailed by a +-0.5 DN variation in radiance (quantization noise): a "Depth sensitivity" indicator (left)
- an 8-bits image_LBS of the spectral bottom reflectance in the range 0-250 tmnov_LBS
- an 8-bits image_LBS of the spectral bottom reflectance NORMALIZED in the range 0-250 menton_LBS Lee Stocking island
- an 8-bits 3-bands BGR composite of normalized bottom reflectance mbnorth_RGBCC_LBS_normalized
- an 8-bits image of bottom typing mbnorth_bottom_typing
- Update a history textfile
- 4SM help services for online help to provide the syntax for the commandline
|
4SM_LUT - use a LUT to map the spatial variations of the effective diffuse attenuation coefficient
|
|
4SM OPTIONS
- Correction for variable illumination in raw CASI flight lines ILS plot transient
- Fill small and isolated NoData holes in a raw CASI 16U_mosaic filling
- Remove Limb Brightening from raw CASI flight lines delimbing
- Equalize flightlines in a CASI mosaic equalize_a_mosaic
- Deglint the data free of sunglint, skyglint, haze, and possibly of adjacency effect
- Smoothing
- pain-Smoothing by a fixed radius circular smoothing window prior to processing,
- smart-Smoothing by dynamic radius circular smoothing window with dynamic smoothing range: sort of an "edge-preserving" smoothing scheme. tmnov_Profile_Raw_Smoothed
- Sub-window
- process only inside any odd-shaped masked zone tmnov_redpolygon
- process only inside any rectangular sub-window
- PANmode : model using a SPOT Pan band in addition to XS bands:
- RLNmode : model depths using the log(Lblue)/log(Lgreen) algorithm published by NOAA
- Bottom Typer : supervised bottom type classification Heron_CASI
- Profiler : plot bottom depth and water column corrected bottom reflectance versus distance Waimanalo
- Seatruth regressor : Waimanalo
- Write
- an 8-bits spectral image of Smoothed and Deglinted data image LeeStockingIsland
- an 8-bits spectral Smoothed_Deglinted_Linearized image tarawa-subset X (a rectangular windos is not deglinted)]
- a 16S bits image of depths in centimeters. Non-shallow pixels are coded at -1 tarawa ZG
- a 8-bits RGB Color Composite from spectral 8-bits RGB image mb4 results
- Profile
- Sea-truth regression : use GMT to draw a Postscript display of the linear regression of Computed_Depths versus Seatruth_Depths caicos caicos negril85 moorea
- Correction for variable illumination in raw CASI flight lines ILS plot transient
- Fill small and isolated NoData holes in a raw CASI 16U_mosaic filling
- Remove Limb Brightening from raw CASI flight lines delimbing
- Equalize flightlines in a CASI mosaic equalize_a_mosaic
- Deglint the data free of sunglint, skyglint, haze, and possibly of adjacency effect tarawa_XS_deglint LeeStocking_Ikonos_deglint
- Smoothing
- pain-Smoothing by a fixed radius circular smoothing window prior to processing,
- smart-Smoothing by dynamic radius circular smoothing window with dynamic smoothing range: sort of an "edge-preserving" smoothing scheme. tmnov_Profile_Raw_Smoothed
- Sub-window
- PANmode : model using a SPOT Pan band in addition to XS bands: Z is truly modeled down to ~10 m Bora Bora
- RLNmode : model depths using the log(Lblue)/log(Lgreen) algorithm published by NOAA Limnology and Oceanography
- Bottom Typer : supervised bottom type classification
- Profiler : plot bottom depth and water column corrected bottom reflectance versus distance Waimanalo
- Seatruth regressor : Waimanalo
- Write
- an 8-bits spectral image of Smoothed and Deglinted data image LeeStockingIsland
- an 8-bits spectral Smoothed_Deglinted_Linearized image tarawa-subset X (a rectangular windos is not deglinted)]
- a 16S bits image of depths in centimeters. Non-shallow pixels are coded at -1 tarawa ZG
- a 8-bits RGB Color Composite from spectral 8-bits RGB image mb4 results
- Profile
- Sea-truth regression : use GMT to draw a Postscript display of the linear regression of Computed_Depths versus Seatruth_Depths caicos caicos negril85 moorea
|
 |
| Busy? 4SM in 10 lines |
Garbage in, Garbage out 
