Help Content > Interferometry Module > Interferometric Tools

Purpose

This functionality enables to correct errors (2π cycle multiples) in the unwrapped phase or a given value in the wrapped phase. Typical errors, which can be edited, are those due to phase jumps causing discontinuities in the unwrapped phase. The process can be executed in a either fully-manual or semi-automatic way.

It is worthwhile to mention that this functionality, even if specifically conceived for the phase editing, could be optionally used to edit any other SARscape product.

Technical Note

The editing is executed by following four sequential steps:

1.Start the process to create a copy of the unwrapped phase.

2.When the process ends, the copied image and the following pop up are shown:
PENEW

3.Create a ROI using the Region of Interest tool found under File > New. The ROI can be imported from a previous process using the Import ROI button.
Note: The region can be made of one or more polygons. Keep in mind that all polygons have to belong to the same ROI and not two different ROIs.

4.Perform the operation needed to correct the phase value. Choose between Increment, Mask and Set. Once the processing is ended, the modified image is loaded in the Manager and is opened.

5.In case of error(s), the process can be reverted using the UNDO button (max 10 steps). If the performed UNDO was not necessary, it is possible to revert to the correct version using the REDO button.

6.When all the needed edits are done, the tool can be closed using the close button. All the intermediary steps are deleted.

It order to update the visualization of the edited file, just move the "Display Scroll Bars" in the ENVI "Image Window".

Input Files

Unwrapped Phase file

File name of the input unwrapped phase (_upha). This file is mandatory.

Parameters - Principal Parameters

Overwrite

By setting this flag, the Edited Unwrapped Phase file is overwritten (if already existing).

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 - 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

Edited Unwrapped Phase file

File name of the output (edited) unwrapped phase. This file is mandatory.

Specific Function(s)

Increment

Enter the "Increment value" (negative values correspond to decrements), to correct the area inside the selected ROI. The phase values can be modified only by 2π multiples. Old ROIs (i.e. already edited), must be previously removed.

Specify the "Limit value" above (if incrementing) or below (if decrementing) which the pixels inside the ROI have not to be modified. These are pixel values.

It is possible perform the action outside the ROI by selecting "Extern ROI". Values inside the ROI are not modified in this case.

If the "increment" action is performed on a "complex" data, the "complex" flag has to be selected and the increment has to be given in radians and not in 2π multiples Note: this action can be performed only inside the ROI.

Undo

Undo the last edit.

Redo

Redo the last undone edit.

In case of "Subtract Component" is undone, it is not possible to perform the "redo" operation.

Mask

The area inside the selected ROI(s) is set to dummy (Not a Number, NaN). Example: lake.

It is possible to mask the region outside the ROI by selecting "Extern ROI". Example: island. In case of complex data, the "complex" flag has to be selected and the masked region is set to 0 for both complex components.

Set

The area inside the selected ROI(s) is set to a unique value, which must be specified.

It is possible to set to a unique value the region outside the ROI by selecting "Extern ROI".

In case of complex data, the "complex" flag has to be selected and the phase in the selected region is set to the specified value. Note: this action can be performed only inside the ROI

Subtract Component

This tool allows to subtract a value on the whole image according to a polynom calculated on the selected region (ROI).

Degree: Degrees of the polynom (1 to 6)

Geocoded: Select this flag if the processed data is geocoded

Complex: Select this flag if the processed data is a complex data. In this case, only the Phase value is decremented.

Note: not all Degrees are possible according to the file is being processed

Commit

Once a step where all the edits performed are considered correct, it is possible to save the curent stage that can be restored if the next edits are not satisfactory. Temporary "undo and redo" files are removed. This button creates a "_back file", which is a copy of the actual processed image, that can be used by the Restore function later.

Restore