snaphu.conf.full

phase unwrapping algorithm for SAR interferometry

#
#   rho0 ~= rhosconst1/ncorrlooks + rhosconst2
#
# Approximately matches curves of Touzi, Lopes, Bruniquel, & Vachon 1999
# (double).
RHOSCONST1	1.3
RHOSCONST2	0.14

# Constants (double) for modeling phase standard deviation as a function 
# of rho:
#
#   sigma ~= rho ^ ( cstd1 + cstd2*log(nlooks) + cstd3*nlooks )
#
# Approximately matches curves of Lee, Hoppel, Mango, & Miller, 1994.
CSTD1		0.4
CSTD2		0.35
CSTD3		0.06

# Default value to use uniformly for true, unbiased correlation if no 
# correlation file is specified and correlation cannot be generated 
# from the available data (double). 
DEFAULTCORR	0.01

# Factor applied to expected minimum measured (biased) correlation.
# Values smaller than the threshold rhominfactor*rho0 are assumed to
# come from zero statistical correlation because of estimator bias (double).
# This is used only in topo mode; for defo mode, use DEFOTHRESHFACTOR.
RHOMINFACTOR	1.3


########################
# PDF model parameters #
########################

# Algorithm costs are based on the negative log pdf:
#
#   cost = -log(f(phi | EI, rho))

# Layover peak location (meters/pixel)
DZLAYPEAK	-2.0

# Factor applied to range layover probability density to get azimuth
# layover probability density (double).  
AZDZFACTOR	0.99 

# Factor applied to slope expected from brightness without layover (double).
# Can account for underestimation of brightness from averaging with 
# neighboring dark pixels when despeckling.
DZEIFACTOR      4.0

# Weight applied to slope expected from brightness without layover (double).
# Must be between zero and one.  Can reduce influence of intensity on 
# nonlayover slope.  This is useful if there are lots of nontopographic
# variations in brightness (ie, changes in surface relfectivity).
DZEIWEIGHT      0.5

# Factor applied to slope expected from brightness with layover (double).
# Can account for underestimation of brightness from averaging with 
# neighboring dark pixels when despeckling.
DZLAYFACTOR	1.0

# Ratio of layover probability density to peak probability density
# for non-layover slopes expected (double).
LAYCONST	0.9

# Factor applied to slope varinace for nonlayover to get falloff of
# probability density after the upper layover slope limit has been 
# exceeded (double).
LAYFALLOFFCONST	2.0

# Minimum value of variance when cast to short integer data type (long).
# Must be greater than 0 to avoid divide-by-zero.
SIGSQSHORTMIN	1

# Fraction of (ambiguity height)^2 to use for slope variance in the 
# presence of layover.  Should usually be less than (1/2)^2 = 0.25.
SIGSQLAYFACTOR	0.1


###############################
# Deformation mode parameters #
###############################

# Factor applied to range discontinuity probability density to get 
# corresponding value for azimuth (double).
DEFOAZDZFACTOR	1.0

# Factor applied to rho0 to get threshold for whether or not phase
# discontinuity is possible (double).  rho0 is the expected, biased 
# correlation measure if true correlation is 0.
DEFOTHRESHFACTOR 1.2

# Maximum phase discontinuity likely (double).  Units are radians or cycles.
# If abrupt phase discontinuities are not expected, this paramter can be 
# set to zero.
DEFOMAX_CYCLE	1.2
#DEFOMAX_RAD	7.5398

# Phase variance (cycles^2) reflecting uncertainty in measurement of 
# actual statistical correlation (double).
SIGSQCORR	0.05

# Ratio of phase discontinuity probability density to peak probability
# density expected for discontinuity-possible pixel differences (double).
# Value of 1 means zero cost for discontinuity, 0 means infinite cost.
DEFOCONST	0.9


########################
# Algorithm parameters #
########################

# Maximum flow (long) to allow in initialization.  If this is zero,
# then the maximum is calculated automatically from the statistical
# cost functions.  To disable, set it to a large value like 9999, but 
# do not overflow the long integer data type.
INITMAXFLOW	9999

# Constant (long) to add to maximum flow expected from statistical 
# cost functions for automatically determining initial maximum 
# flow (see above).
ARCMAXFLOWCONST	3

# Maximum flow increment (long) for solver.  Not the same as maximum 
# flow possible.
MAXFLOW		4

# Number of pixels in row and column dimensions to use in sliding average
# window used for normalizing intensity values (long).
KROWEI		65
KCOLEI		257

# Number of pixels to use in sliding window average used for averaging 
# wrapped gradients to get mean non-layover slope, in directions parallel
# and perpendicular to the examined phase difference (long).
KPARDPSI	7
KPERPDPSI	7

# Threshold precision for iterative numerical calculations (double).
THRESHOLD	0.001

# Initial value of range slope for dzrcrit numerical solution (double, 
# meters/pixel)
INITDZR		2048.0

# Initial range slope stepsize in dzrhomax numerical solution (double, 
# meters/pixel)
INITDZSTEP	100.0

# Maximum cost allowd for scalar MST costs and for estimating number of 
# buckets needed for solver routine (double).
MAXCOST		1000.0

# Scaling constant factor applied to double precision costs to get 
# integer costs (double).
COSTSCALE	100.0

# Ambiguity height for autoscaling COSTSCALE to equal 100 (double,
# meters).  COSTSCALE is automatically adjusted to be inversely
# proportional to the midswath ambigutiy height in topography mode.
COSTSCALEAMBIGHT 80.0

# Step size (double, radians) for dzrhomax lookup table.  The index is
# on the local flat-earth incidence angle; this is the sample spacing
# in the table.
DNOMINCANGLE	0.01

# Integer spacing that represents one unit of flow or one cycle of phase
# when storing costs as short integer types (long).
NSHORTCYCLE	200

# Fraction of total number of nodes to add in each tree expansion
# phase of solver algorithm (double).
MAXNEWNODECONST	0.0008

# Number of cycles to allow for a call to solver with a specific flow
# increment delta and still consider that increment done.  Ideally
# it would be zero, but scaling for different deltas may leave some 
# negative cycles that won't affect solution much.  Comment this out 
# to automatically determine the number based on the size of the 
# interferogram.
#MAXNFLOWCYCLES	10

# Fraction of the number of pixels to use as the maximum number of 
# cycles allowed for a specific flow increment if MAXNFLOWCYCLES 
# is not given.
MAXCYCLEFRACTION 0.00001

# Determines how the source or root of the tree is chosen for the 
# modified network-simplex solver.  If SOURCEMODE is zero, the 
# ground node is used as the root (usually fastest).  Otherwise, 
# SOURCEMODE should be 1 or -1, and the root is the endpoint of the 
# longest chain of flow greater than or equal to the current flow 
# increment, where the sign of SOURCEMODE determines which end of the
# chain is used.
SOURCEMODE	0

# Scale factor (long) for cs2 MCF initializations.  A larger number
# gives greater speed, but uses more memory.
CS2SCALEFACTOR	8


##############################################
# File names for dumping intermediate arrays #
##############################################

# If the following file names are given, the corresponding intermediate
# array will be dumped to that file.  Otherwise, the array is not dumped.
# These filenames override the default file names assigned when 
# DEBUG is TRUE.

# Unwrapped initialization 
# INITFILE 		snaphu.init

# Flow corresponding to unwrapped solution
# FLOWFILE		snaphu.flow

# Normalized, despeckled SAR image intensity
# EIFILE		snaphu.ei

# Statistical costs for azimuth
# ROWCOSTFILE		snaphu.rowcost

# Statistical costs for range
# COLCOSTFILE		snaphu.colcost

# Scalar initialization costs for azimuth
# MSTROWCOSTFILE	snaphu.mstrowcost

# Scalar initialization costs for range
# MSTCOLCOSTFILE	snaphu.mstcolcost

# Scalar initialization costs for both azimuth and range, concatenated
# MSTCOSTSFILE		snaphu.mstcosts

# Correlation coefficient magnitude (before clipping into [0,1] interval)
# RAWCORRDUMPFILE	snaphu.rawcorr

# Correlation coefficient magnitude (after clipping into [0,1] interval)
# CORRDUMPFILE		snaphu.corr


###############################
# Piece extraction parameters #
###############################

# These parameters (long, dimensionless) allow only a subset of the
# input data files to be read and unwrapped.  The upper left corner of
# the subset is at row PIECEFIRSTROW and column PIECEFIRSTCOL, with
# both indexed from 1 (that is, the upper left corner is pixel 1,1).
# The output will be PIECENROW rows x PIECENCOL columns in size.
# These parameters cannot be used in tile mode.  If PIECENROW or
# PIECENCOL is zero, the full depth or width of the input is
# unwrapped.
# PIECEFIRSTROW		1
# PIECEFIRSTCOL		1
# PIECENROW		0
# PIECENCOL		0


################
# Tile control #
################

# Parameters in this section describe how the input files will be 
# tiled.  This is mainly used for tiling, in which different
# patches of the interferogram are unwrapped separately.

# Number of rows and columns of tiles into which the data files are
# to be broken up.
# NTILEROW		1
# NTILECOL		1

# Overlap, in pixels, between neighboring tiles.
# ROWOVRLP		0
# COLOVRLP		0

# Maximum number of child processes to start for parallel tile
# unwrapping.
# NPROC			1

# Cost threshold to use for determining boundaries of reliable regions
# (long, dimensionless; scaled according to other cost constants).
# Larger cost threshold implies smaller regions---safer, but
# more expensive computationally.  
# TILECOSTTHRESH 	500

# Minimum size (long, pixels) of a reliable region in tile mode.  
# MINREGIONSIZE		100

# Extra weight applied to secondary arcs on tile edges.
# TILEEDGEWEIGHT	2.5

# Maximum flow magnitude (long) whose cost will be stored in the secondary 
# cost lookup table.  Secondary costs larger than this will be approximated
# by a quadratic function.
# SCNDRYARCFLOWMAX	8

# The program will remove temporary tile files if this is set.
# RMTMPTILE 		FALSE

# If this is set to anything besides FALSE, the program will skip
# the unwrapping step and only assemble temporary tile files from a previous 
# invocation saved in the directory whose name is given here.  The tile size 
# parameters and file names must be the same.
# ASSEMBLEONLY		tiledir


###############################
# Connected component control #
###############################

# Grow connected components mask and write to output file specified.
# CONNCOMPFILE		snaphu.conncomp

# Grow connected components mask from unwrapped input then exit if TRUE.
# Output is written to the file specified by CONNCOMPFILE.
# REGROWCONNCOMPS	FALSE

# Minimum size of a single connected component, as a fraction (double)
# of the total number of pixels in tile.
# MINCONNCOMPFRAC 	0.01

# Cost threshold for connected components (long).  Higher threshold will
# give smaller connected components.
# CONNCOMPTHRESH	300

# Maximum number of connected components per tile (long).
# MAXNCOMPS 		32

# End of snaphu configuration file