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Purpose

 

The residual phase frequency is estimated on the wrapped phase (interferogram), removed from it and added to the synthetic phase (_sint).

 

The objective it is to simplify the "Phase Unwrapping" step.

 

Technical Note

 

The difference with respect to the Residual Phase Frequency removal, which is possible by setting the relevant Preferences, is that this is more flexible/tunable as more parameters can be set.

 

The "Ground Control Point file" can be optionally entered for the residual phase calculation. It has the same meaning of the "Orbital GCP file" used in the Refinement and Re-Flattening process. If it is used, the Ground Control Points must be well distributed throughout the entire scene and they have not to be located on areas where topographic fringes remained "unflattened".

 

It must be noted that, only whether the input and output file names are the same or the "Output Root Name" is missing, the original synthetic (_sint) and differential (_dint) interferograms, which are modified as result of phase removal, are saved with the prefix "original_".

 

Azimuth Window Size

The window size must be larger than the orbital fringe dimension (in pixels) in order to have an optimal performance. If the window is too big, with respect to the image size, the program will automatically reduce it.

 

Range Window Size        

The window size must be larger than the orbital fringe dimension (in pixels) in order to have an optimal performance. If the window is too big, with respect to the image size, the program will automatically reduce it.

 

Polynomial Degree

The number of coefficients (from 1 to 10) used for the residual phase removal. It makes sense to have this value set at least to 2, since a dominant dependency in range is expected.

φ = K1 + K2X + K3Y + K4X2 + K5XY + K6Y2+ K7X3 + K8X2Y + K9XY2 + K10Y3

Low Pass Filter m

Window size (meters) for the Low Pass atmospheric removal, in range and azimuth direction, which is used for the removal process. If set to zero, the Low Pass removal is not applied. Suggested values are more than 15000 meters, only in case of small spatial size displacement pattern.
 

Input Files

 

Interferogram File

File name of the differential interferogram (_dint, _fint). This file is mandatory.

 

Optional Files

 

Win center Shape File

Shape file (point type) (.shp) in slant range geometry for the positioning of the windows for estimating the residual frequency. If this file is not inserted, the windows will be distributed on a regular grid (using the “Azimuth Window Number” and “Range Window Number” parameters). This file is optional.

Coherence File

File name of the coherence image (_cc). This file is mandatory.

 

Optional Files

 

Geometry GCP File

Either a previously created Ground Control Point file (.xml) is loaded (Load GCP File) or  the interface to create a new Ground Control Point file is automatically loaded (Create GCP File, refer to the "Tools>Generate Ground Control Point" for details). This file is optional.

 

Parameters - Principal Parameters

 

Azimuth Window Size

Window Size in azimuth direction – better using power of 2 values – which is used to estimate the local fringe frequency.

 

Range Window Size        

Window Size in range direction – better using power of 2 values – which is used to estimate the local fringe frequency.

 

Azimuth Window Number

Number of windows, in azimuth direction, which are used for the removal process. If set to zero, the polynomial removal is not applied.

 

Range Window Number

Number of windows, in range direction, which are used for the removal process. If set to zero, the polynomial removal is not applied.

 

Polynomial Degree

The number of coefficients (from 1 to 10) used for the residual phase removal. Refer to the flattening section of the Flattening Preferences for further informations.

 

Low Pass Filter m

Window size in meter for the Low Pass Filter. If set to zero, the Low Pass removal is not applied.

 

Parameters - Global

 

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Flattening

 

It brings to the flattening section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Parameters - Other Parameters

 

It brings to the general section of the Preferences parameters. Any modified value will be used and stored for further processing sessions.

 

Output Files

 

Output Root Name

Name of the output root. This file is mandatory.

 

_dint

Flattened corrected interferogram with the associated header files (.sml, .hdr). This file is generated only if the input is an unfiltered interferogram (_dint).

 

_fint

Flattened and filtered corrected interferogram with the associated header files (.sml, .hdr). This file is generated only if the input is a flattened-filtered interferogram (_fint).

 

.shp

 

Details specific to the Units of Measure and Nomenclature of the output products can be found in the Data Format section.

 

General Functions

 

Exec

The processing step is executed.

 

Store Batch        

The processing step is stored in the batch list. The Batch Browser button allows to load the batch processing list.

 

Close        

The window will be closed.

 

Help

Specific help document section.

 

 

Specific Function(s)

 

None.

 

See Also

 

Task, SARscapeBatch object, SARscapeBatch script example

 

References

 

None.