ANSI-C program: multi_real.c
NAME
multi_real - This program is used to resample a selected region
of a real-valued image. Both decimation and oversampling are
supported.
SYNOPSIS
multi_real <real_input > <OFF_par_in >
<real_output> <OFF_par_out> [rlks] [azlks] [loff]
[nlines] [roff] [nsamp]
| <real_input> | input real image file |
| <OFF_par_in> | interferogram/offset parameter file for input image |
| <real_output> | output multi-look or interpolated real data file |
| <OFF_par_out> | interferogram/offset parameter file for output, use existing parameter file if available |
| [rlks] | number of range looks, values < -1, interpreted as an image magnification factor (default=1) |
| [azlks] | number azimuth looks, values < -1, interpreted as an image magnification factor (default=1) |
| [loff] | line offset to starting line (default=0) |
| [nlines] | number of lines (default=0, to end of file) |
| [roff] | offset to starting range sample (default=0) |
| [nsamp] | number of range samples to extract (default=to end of line) |
EXAMPLES
Average and decimate a complex correlation file by a factor of
2:
multi_real 8560_8059.cc 8560_8059.off 8560_8059_2.cc
8560_8059_2.off 2 2
Oversample an unwrapped phase file by a factor of 2:
multi_real 8560_8059.unw 8560_8059.off unw_2.unw unw_2.off
-2 -2
DESCRIPTION
multi_real extracts a region from a real-valued data
file and averages the data using the rlks and
azlks parameters defined on the command line. If the
number of range and azimuth looks is set to 1, then the desired
region is extracted and the values are not altered. If the output
image is decimated, averaging of the data is performed to reduce
noise, using rlks samples in range and azlks
azimuth samples for each output sample.
Alternately, the program can be used to oversample a segment of an image with the magnification factors specified on the command line. These integer factors are given as negative rather than positive values for the rlks and azlks parameters. Interpolation in one dimension and decimation in the other is not permitted. Bilinear interpolation is used to resample the data.
Normally a new parameter file describing the processed output image geometry is created. When interpolating data however, the program first checks if there is an existing parameter file. If it exists is is used to determine the size of the output image to ensure that the oversampled images have the same geometry as other data sets prior to averaging and subsampling. In the case of an existing parameter file, the parameters loff, nlines, roff, and nsamp must all be default values.SEE ALSO
typedef_ISP.h
© Copyrights for Documentation, Users Guide and Reference Manual by Gamma Remote Sensing, 2000.
UW, CW, last change 3-Nov-2000.