snaphu_man1.html

phase unwrapping algorithm for SAR interferometry

are masked out. Parameters for this option can be set in the
configuration file. The connected component file is composed
of unsigned characters, with all pixels of the same value
belonging to the same connected component and zero
corresponding to masked pixels.</td></table><p>

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<b>-G</b> <i>maskfile</i></td></table><p>

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Grow a connected component mask (see the <b>-g</b> option)
for the input data array, assuming that it is already
unwrapped, and write the mask to the file <i>maskfile</i>.
Statistical cost functions are computed for forming the
mask, but a new unwrapped solution is not
computed.</td></table><p>

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<b>-h</b></td></table><p>

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Print a help message summarizing command-line options and
exit.</td></table><p>

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<b>-i</b></td></table><p>

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Run in initialize-only mode. Normally, <b>snaphu</b> uses
either an approximate minimum spanning tree (MST) algorithm
or a minimum cost flow (MCF) algorithm for generating the
initialization to its iterative, modified network-simplex
solver. If <b>-i</b> is given, the initialization is written
to the output and the program exits without running the
iterative solver.</td></table><p>

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<b>-l</b> <i>logfile</i></td></table><p>

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Log all runtime parameters and some other environment
information into the specified file. The log file is a text
file in the same format as a configuration
file.</td></table><p>

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<b>-m</b> <i>magfile</i></td></table><p>

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Read interferogram magnitude data from the specified file.
This option is useful mainly if the wrapped-phase input file
is given as a set of real phase values rather than complex
interferogram values. The interferogram magnitude is used to
form a coherence estimate if appropriate amplitude data are
given as well. The default file format is FLOAT_DATA. If the
formats ALT_LINE_DATA or ALT_SAMPLE_DATA are used, the
magnitude should be in the first data channel of the file;
the second channel is ignored. If the COMPLEX_DATA format is
used, the phase information is ignored.</td></table><p>

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<b>-n</b></td></table><p>

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Run in no-statistical-costs mode. If the <b>-i</b> or
<b>-p</b> options are given, <b>snaphu</b> will not use
statistical costs. Information from a weight file (<b>-w</b>
option) will still be used if given.</td></table><p>

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<b>-o</b> <i>outfile</i></td></table><p>

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Write the unwrapped output to file called <i>outfile</i>. If
the file formats ALT_LINE_DATA (default) or ALT_SAMPLE_DATA
are used, the unwrapped phase is written into the second
data channel, while the interferogram magnitude is written
into the first channel. The format FLOAT_DATA may also be
used.</td></table><p>

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<b>-p</b> <i>value</i></td></table><p>

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Run in Lp-norm mode with p=<i>value</i>, where <i>value</i>
is a nonnegative decimal. Instead of statistical cost
functions, the program uses Lp cost functions with
statistically based weights (unless <b>-n</b> is also
given). Solutions are still always congruent. Moreover,
congruence is enforced within the solver routine, not as a
post-optimization processing step. Therefore, if p=2, for
example, least-squares cost functions are used, but the
solution will probably be more accurate than one generated
from a transform-based least-squares algorithm.</td></table><p>

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<b>-q</b></td></table><p>

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Run in quantify-only mode. The input data are assumed to be
unwrapped already, and the total cost of this solution is
calculated and printed. The unwrapped phase is wrapped
assuming congruence for the cost calculation. Round-off
errors may limit the precision of the quantified cost. See
the <b>-u</b> option for allowable file
formats.</td></table><p>

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<b>-s</b></td></table><p>

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Run in smooth-solution mode. The problem statistics and
resulting cost functions are based on the assumption that
the true unwrapped phase represents a generic surface with
no discontinuities. This is the same as deformation mode
with the DEFOMAX parameter set to zero.</td></table><p>

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<b>-t</b></td></table><p>

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Run in topography mode. The problem statistics and resulting
cost functions are based on the assumption that the true
unwrapped phase represents surface elevation. This is the
default.</td></table><p>

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<b>-u</b></td></table><p>

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Assume that the input file is unwrapped rather than wrapped.
The algorithm makes iterative improvements to this solution
instead of using an initialization routine. The input file
may be in the formats ALT_LINE_DATA (default) or
ALT_SAMPLE_DATA; the interferogram magnitude should be in
the first data channel and the unwrapped phase should be in
the second data channel. The format FLOAT_DATA may also be
used.</td></table><p>

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<b>-v</b></td></table><p>

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Run in verbose mode. Extra information on the algorithm's
progress is printed to the standard output.</td></table><p>

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<b>-w</b> <i>weightfile</i></td></table><p>

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Read external, scalar weights from file <i>weightfile</i>.
The weights, which should be positive short integers, are
applied to whichever cost functions are used. There is one
weight value for each arc in the network, so
<i>weightfile</i> should be the concatenation of raster
horizontal-flow and vertical-flow arc weights. Thus, for an
N row by M column interferogram, <i>weightfile</i> would
consist of a rasterized (N-1) by M array followed by a
rasterized N by (M-1) array of short integer data. This
option is not well tested.</td></table><p>

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<b>--aa</b> <i>ampfile1 ampfile2</i></td></table><p>

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Amplitude data are read from the files specified. The data
from the two individual SAR images forming the interferogram
are assumed to be separately stored in files <i>ampfile1</i>
and <i>ampfile2</i>. These files should be in the format
FLOAT_DATA. This option is similar to the <b>-a</b>
option.</td></table><p>

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<b>--AA</b> <i>pwrfile1 pwrfile2</i></td></table><p>

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Similar to the <b>--aa</b> option, but power data are read
from the specified files.</td></table><p>

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<b>--assemble</b> <i>dirname</i></td></table><p>

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