Gamma DIFF: Reference Manual

quad_sub

ANSI-C program: quad_sub.c

NAME
quad_sub - Subtract quadratic model phase function from a differential interferogram

SYNOPSIS
quad_sub <int-1> <DIFF_par> <int-2> [int_type] [mode]

<int-1>	(input) differential interferogram (float or fcomplex)
<DIFF_par>	(input) DIFF processing parameter file
<int-2>	(output) output interferogram (same format as input)
[int_type]	interferogram type: 0: unwrapped interferometric phase (float) 1: fcomplex interferogram
[mode]	add or subtract phase model: 0: subtract phase model from DIFF_par (default) 1: add phase model from DIFF_par

EXAMPLE
quad_sub 20120429.TSX_HH_20120429.TDX_HH.adf.diff 20120429.TSX_HH_20120429.TDX_HH.diff_par 20120429.TSX_HH_20120429.TDX_HH.adf.qs_diff 1 0

input interferogram is fcomplex format. Subtracting the polynomial phase model stored in the DIFF_par

DESCRIPTION
quad_sub subtracts a 2D quadratic phase unction from either an unwrapped or wrapped interferogram. The 2D quadratic phase function parameters are stored in the DIFF_par parameter file. These parameters are estimated using the quad_fit program that requires an unwrapped interferogram as input. The phase model function has 3 possible forms depending on the model option used with quad_fit .

model 0:  a0  +  a1*x   +  a2*y
    +  a3*x*y  +  a4*x^2  +  a5 *y^2
  : linear and quadratic phase ramps in range and azimuth

  model 1:  a0  +  a4*x^2 +  a5*y^2
    a1 = 0.0, a2 = 0.0, a3 = 0.0   : quadratic phase
  ramp in range and azimuth

  model 2:  a0  +  a1*x   +  a2*y  
    a2 = 0.0, a4 = 0.0, a5 = 0.0   : linear phase
  ramp in range and azimuth

The user has the option of either adding or subtracting the phase model from the interferogram.

The data format of the output interferogram is the same as the input interferogram

SEE ALSO
quad_fit, sub_phase, typedef_ISP.h, typedef_DIFF.h.