Gamma ISP: Reference Manual

corr_flag

NAME
corr_flag - Generates flagfile used throughout the various steps necessary for the unwrapping of the interferometric phase.

SYNOPSIS
corr_flag <corr_file> <flag_file> <width> <corr_thr> [xmin] [xmax] [ymin] [ymax] [border]

<corr_file>	(input) interferometric correlation file
<flag_file>	(output) phase unwrapping flag filename
<width>	number of samples/row
<corr_thr>	correlation threshold (0 --> 1.0)
[xmin]	starting range pixel offset (default = 0)
[xmax]	last range pixel offset (default = width-1)
[ymin]	starting azimuth row offset, relative to start (default = 0)
[ymax]	last azimuth row offset, relative to start (default = nlines-1)
[border]	effective range of low coherence pixels to set low coherence flag (default = 2)

EXAMPLE
corr_flag 1352_1610.cc 1352_1610.flag 2500 0.3

DESCRIPTION
corr_flag creates a flagfile to be used by the programs used for the various phase unwrapping steps. It reads the correlation file (as generated by cc_ave). Areas of interferometric correlations are marked in the flagfile as these areas will be avoided later in the unwrapping of the interferometric phase.

Other programs (residue, tree_cc, grasses) will add further information to the flag file.

For each pixel a flag of 8 bits is stored. The meaning of the individual bits is explained in the typedef_ISP.h file.

The correlation threshold can be defined.

Individual flags of the flagfile can be reset using clear_flag.

The information contained in the flagfile can be displayed with the program disflag.

In addition to the low coherence pixels pixels within a short distance from low coherence pixels are marked with the low coherence flag. The reason to do this is the finite size of the coherence estimation window. The default border around the low coherence pixels which is also included is 2 pixels.

SEE ALSO
cc_ave, clear_flag, disflag, rastree.