GAMMA Interferometric Point Target Analysis Software (IPTA): Reference Manual

unw_model_pt

NAME
unw_model_pt - unwrap complex interferogram using a phase model (single record or all records)

SYNOPSIS
unw_model_pt <plist> <pmask> <pint> <rec_num> <punw_model> <punw> [np_ref] [ref_ph]

<plist>	(input) point list (int)
<pmask>	(input) point data stack of mask values (uchar, set to - to accept all points)
<pint>	(input) point data stack of interferograms (fcomplex)
<rec_num>	record number to process (default -: all records)
<punw_model>	(input) point data stack of approximate unwrapped phases (float)
<punw>	(output) point data stack of unwrapped phases (float)
[np_ref]	phase reference point number (beginning from 1, default=1)
[ref_ph]	phase value to use at np_ref (if not provided value of unw_model is used)

EXAMPLE
unw_model_pt testsite.plist testsite.pmask testsite.pdiff 3 testsite.punw_model testsite.pdiff.unw 824 0.0

Unwraps the interferometric phase for record 3 of the input stack of interferograms, assuming that the unwrapped phases lie within PI of the provided unwrapped phase model. Point 824 is used as reference and the phase at this reference point is set to 0.0.

unw_model_pt testsite.plist testsite.pmask testsite.pdiff - testsite.punw_model testsite.pdiff.unw

Unwraps the interferometric phase for all records of the input stack of interferograms, assuming that the unwrapped phases lie within PI of the provided unwrapped phase model. Point 1 is used as reference and the phase at this reference point is set to the value of the model.

INSTALLATION
Source code unw_model_pt.c in ./IPTA/src, executable version unw_model_pt in ./IPTA/bin

DESCRIPTION
unw_model_pt conducts a very simple model based phase unwrapping for interferograms in point data format. This can be done for a single record of the stack of interferograms or all records.

The coordinates of the points considered are defined in the point list. The optional mask file (in point data format) indicates for each point if it is valid (1, i.e. considered) or not valid (0, excluded).

The input interferograms are provided as a point data stack. This stack is of fcomplex type. The phase model is provided as a point data stack of type float with the values coresponding to unwrapped phases. The type of the output stack of unwrapped interferograms is of float format.

Unwrapped phases are calculated for each valid point of the point list. Valid points are points with a non-zero input interferogram value, a non-zero point mask value (if provided), and a non-zero raster mask value (if provided).

In the model based phase unwrapping it is assumed that the unwrapped phases of the model are almost accurate to within PI. Each complex valued phase is converted to the unwrapped phase which is within PI of the phase model such that a re-wrapping would result in the original wrapped phase.

Only at the end a phase offset as can optionally be indicated by specifying the phase for an referent point, is subtracted from each unwrapped phase value.

The unwrapped phases are written to the output point data stack of unwrapped phases at the indicated record number.

If a new output stack name is indicated the stack is created. Indicating a record number larger than the highest record number of the indicated stack results in an increase of the stack size.

The reliability of unw_model_pt depends on the quality of the phase model used. In the case the phase model is reliable enough, unw_model_pt is a very straight-forward (and efficient) way of phase unwrapping.

To display the complex or real valued input or output interferograms contained in the point data stack the programs pt2data or pt2d can be used to convert the point data to raster data format which can then be displayed using conventional display programs.

OPTIONS
none.

SEE ALSO
mcf_pt, def_mod_pt, multi_def_pt, pt2data, pt2d, ipta.h.