ANSI-C program: adapt_filt.c
NAME
adapt_filt - Adaptive filtering (adaptive to the local slope,
respectively fringe rate) of the interferometric phase.
SYNOPSIS
adapt_filt <int> <sm> <width>
[low_SNR_thr] [filt_width] [xmin] [xmax] [ymin]
[ymax]
| <int> | complex interferogram image filename (phase trend removed) |
| <sm> | smoothed interferogram filename (for filtered data output) |
| <width> | number of samples/row |
| [low_SNR_thr] | low SNR threshold (default = 0.25 |
| [filt_width] | filter width in pixels (default = 4.0) |
| [xmin] | offset to starting range pixel (default = 0) |
| [xmax] | offset last range pixel (default = width-1) |
| [ymin] | offset to starting azimuth row (default = 0) |
| [ymax] | offset to last azimuth row (default = nlines-1) |
EXAMPLE
adapt_filt 1352_1610.flt 1352_1610.sm 2500 0.25
4.0
DESCRIPTION
adapt_filt reads the complex interferogram (for ERS-1 usually
with the phase trend removed), computes locally the slope, and
averages the interferometric phase along the local slope. The
goal of the adaptive filtering step is to reduce phase noise and
reduce the number of residues (problematic location for phase
unwrapping). The filtering window size is determined by the user
input. The value approximates the size of the smoothing window. A
Kaiser window function is used to improve the averaging filter
frequency and spatial response. The smoothed (respectively)
filtered interferometric phase is written out to a file. The
dimensions of the smoothed interferogram file is identical to
that of the interferogram file. Therefore, the same programs to
generate SUN rasterfiles and display programs may be used with
identical parameters.
SEE ALSO
typedef_ISP.h
© Copyrights for Documentation, Users Guide and Reference Manual by Gamma Remote Sensing, 2005.
UW, CW, last change 19-Jul-2005.