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<< Click to Display Table of Contents >> Preferences specific - Mosaic and Filtering |
  
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<< Click to Display Table of Contents >> Preferences specific - Mosaic and Filtering |
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Purpose
This panel enables to set the default processing parameters, which are used in the Filtering and Mosaicing functions.
Technical Note
The setting of these processing defaults is relevant to the Conventional Mosaic>Last Overlay, Gradient Mosaic and to the Anisotropic Non-Linear Diffusion Filtering (Single image and Multi-temporal).
Parameters - Mosaic and Filtering
Conventional Mosaic
Weight Min in Range
The image histogram matching is performed using only those pixel whose value (expressed in linear scale) is equal or higher than this threshold.
Weight Max in Range
The image histogram matching is performed using only those pixel whose value (expressed in linear scale) is equal or lower than this threshold.
Last Mosaic Histogram Scaling
By setting this flag, the "Last Overlay" mosaic is performed after an image histogram matching aimed at reducing as much as possible average value differences in the overlapping areas.
Gradient Mosaic
Gradient Mosaic Window Size
The window for the calculation of the ratio between standard deviation and mean. This value is used for the edge identification: the larger the window the better the edge detection. Evident edges are detected by large windows.
Threshold
This value can vary from 0 to 1. In case only sharp/evident edges have to be identified a value close to 1 must be used.
Number of Point Abs Calib
The number of points, which are identified on each of the image overlapping areas, can be specified. The calibration polynomia are calculated in order to calibrate the radiometric value in the whole image (all input data). The larger this value the more precise the calibration, the longer the processing time.
Number of Point Krig Calib
The number of points, which are identified on each of the image overlapping areas, can be specified. This calibration is used for correcting the radiometric value in the overlapping area. The larger this value the more precise the calibration, the longer the processing time.
Anisotropic Non-Linear Diffusion
ANLD Gaussian Blur By setting this flag to True a preliminary Gaussian Blur filtering with fixed window size of 3x3 is applied.
ANLD Maximum time
This parameter can be used to tune the filtering iterations number. The higher, the greater the number of filtering iterations.
ANLD Lambda
This parameter is a positive float value that can be used to reshape the gradient sensitivity function of the diffusion.
ANLD K factor
This value controls the sensitivity to edges and it usually chosen experimentally. Low values of this parameters produce smooth curves (isotropic diffusion decreases slowly around edges) whereas high values lead to sharper curves (isotropic diffusion decreases quickly around edges).
Non-Local Filtering
Non-Local H factor
It modules the filter intensity. The higher the value, the higher the strength of the filter.
Non-Local T factor
It modules the filter intensity during the iterative processing. The lower the value, the higher details preserved.
Non-Local Average Window Size
The size of the weighted average performed by the filter. By increasing the window size, the waving effect over homogeneous areas is reduced. However, the processing time exponentially increases in function of the window size.
Non-Local Similarity Kernel Size
The kernel size used to quantify the similarity probability (weight) for the weighted average.
Non-Local Similarity Min Kernel Size
This parameter activates the similarity probability kernel adaptivity (if this value is lower than the similarity kernel size).
Non-Local Number of iteration
Number of iterations. It is mandatory an odd number, where 1 means that no iteration is applied. For values higher than 3, it provides minor improvements with higher processing time.
Non-Local Lower Bound Threshold (dB)
Threshold on calibrated power values to reject dark objects outliers from the similarity weighted mean estimation.
Values lower than this threshold (i.e. dark points identified as water) are not considered in the neighborhood filtering selection.
Non-Local Upper Bound Threshold (dB)
Threshold on calibrated power values to reject bright outliers objects from the similarity weighted mean estimation.
Values higher than this threshold (i.e. bright points identified as point target) are not considered in the neighborhood filtering selection.
Non-Local Ratio threshold (dB)
Threshold on ratio between calibrated power values to reject the outliers from the similarity mean estimation.
Ratio values between the observed and the neighborhood point higher than this threshold are not considered in the filtering process. This parameter is associated to the Non-Local Lower Bound Threshold (dB) or Non-Local Upper Bound Threshold (dB) in neighborhood filtering selection.
Non-Local Maximum Dissimilarity
Maximum dissimilarity to avoid float underflow during the similarity weight estimation.
Equivalent Number of Looks (ENL)
The Equivalent Number of Looks is equivalent to the number of independent intensity values averaged per pixel during the multi-looking process. This parameter can be easily estimated over a homogeneous (stationary) sample in the input intensity data according to:
ENL = mean2 / standard deviation2
If the ENL is not set (i.e., it is set to the special value -1), it is automatically estimated via an analysis over the whole image.
General Functions
Load Preferences
It allows loading specific Preferences tthirteen different settings as possible alternative default processing values.
Load
It allows loading an .xml, .sml or .txt file where SARscape common Preferences where previously saved.
Save
It allows saving SARscape common Preferences for a future processing using the same preferences characteristics.
Help
Specific help document section.
Ok
The selected default processing parameters are loaded.
Cancel
The window will be closed.
Specific Function(s)
None.
References
None.