Gamma DIFF/GO: Reference Manual

WSS_mosaic

NAME
WSS_mosaic - mosaic MLI images and interferograms produced from ESA Wide-Swath SLC products

SYNOPSIS
usage: WSS_mosaic <WSS_tab> <SLC_par> <WSS_data> <type>

<WSS_tab>	(input) two column list of MLI data files and MLI image parameter files for each sub-swath (including paths) required file order: SS1, SS2, SS3, SS4, SS5
<SLC_par>	(output) ISP image parameter file for the mosaicked WSS MLI image
<WSS_data>	(output) WSS mosaicked interferogram or MLI image
<type >	WSS data type: 0: FLOAT 1: FCOMPLEX

EXAMPLE:

To mosiac the slant range swath MLI images of the 5 WSS sub-swaths:

WSS_mosaic WSS_20040208_mli_tab
  20040208_mosaic.slc.par 20040208_mosaic.mli 0

To mosiac the slant range swath interferograms of the 5 WSS sub-swaths:

WSS_mosaic WSS_20040208_20030921_int_tab 20040208_mosaic.slc.par 20040208_20030921_mosaic.int 1

DESCRIPTION
WSS_mosaic is a program to mosiac the subswaths of the ESA Widw-Swath SLC (WSS) products produced from ASAR scansar data. The WSS products are generated such that the output SLC samples are on a 0-Doppler grid. This has th consequence that the images and interferograms from each of the sub-swaths can be exactly mosaicked using nearest-neighbor resampling. The processing sequence to produce a mosaicked WSS interferogram :

Extract the 5 WSS subswath data sets from the ASAR image product obtained from ESA using ISP program par_ASAR.
Generate multi-look intensity (MLI) images from each of the sub-swaths. The individual bursts are detected and summed to produce the MLI image using ISP program multi_SLC_WSS.c
Terrain geocode each of the MLI image swaths using gc_map, as well as the other programs used for terrain geocoding and refinement
Resample WSS data to the reference image using rdc_trans, and WSS_interp_lt , then generate an MLI image of the resampled SLC (multi_SLC_WSS) and measure the offsets between the MLI image of the resampled WSS scene and the MLI image of the reference scene. The offsets are used to generate an offset polynomial model using offset_fitm.that is then applied in WSS_interp_lt to improve the coregistration.
Generate the interferogram for the sub-swath using WSS_intf.c
Repeat the above steps 2-5 for each of the 5 sub-swaths.
Give the MLI images and interferograms of the 5 sub-swaths, mosaic the MLI images using WSS_mosaic with data type set to 0 (FLOAT).
Given the interferograms from the subswaths that are coregistered to the MLI image of the reference track, mosaic using WSS_ with the data type set to 1 (FCOMPLEX)

To mosaic the data, a WSS_tab text file is entered on the command line that contains the file names and the image parameter file names for each of the swaths in the mosaic. For example, to mosiac
the MLI images from each of the sub-swaths, the WSS_tab contains the following lines for a particular WSS image:

slc/20040208/20040208.VV.IS1.mli slc/20040208/20040208.VV.IS1.mli.par slc/20040208/20040208.VV.IS2.mli slc/20040208/20040208.VV.IS2.mli.par slc/20040208/20040208.VV.IS3.mli slc/20040208/20040208.VV.IS3.mli.par slc/20040208/20040208.VV.IS4.mli slc/20040208/20040208.VV.IS4.mli.par slc/20040208/20040208.VV.IS5.mli slc/20040208/20040208.VV.IS5.mli.par

Fore the interferograms swaths, the WSS_tab has appears as below.

int/20040208_20030921/20040208_20030921.IS1.int slc/20040208/20040208.VV.IS1.mli.par int/20040208_20030921/20040208_20030921.IS2.int slc/20040208/20040208.VV.IS2.mli.par int/20040208_20030921/20040208_20030921.IS3.int slc/20040208/20040208.VV.IS3.mli.par int/20040208_20030921/20040208_20030921.IS4.int slc/20040208/20040208.VV.IS4.mli.par int/20040208_20030921/20040208_20030921.IS5.int slc/20040208/20040208.VV.IS5.mli.par

Each line in the WSS_tab file contains a pair of entries. The first is the data file and the second is the MLI image parameter file that is describes the geometry. In this particular example the 5 swaths are denoted IS1 to IS5. The reference track is 20040208. Note also that fewer thn 5 swaths can be specified in the WSS_tab, but they must be in increasing order of slant range and the sub-swaths must be adjoining

Note that the interferogram must be coregistered to the MLI for each subswath. The WSS data are not multi-looked in range, only 1 range look is taken. In this way the images have the best range resolution possible and support the larest possible value of perpendicular baseline, given the available range bandwidth and imaging geometry.

The output SLC_par image parameter file constains the parameters of the mosaicked image. It contains the same parameters if either MLI images or interferograms are mosaicked. Finally the type command line parameter specifies if MLI images in FLOAT format or FCOMPLEX interferograms are specified in the WSS_tab.