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<Ambrals Forward Model Functions>
ambralsfor.c: Ambrals forward model functions
ambralsfor.h: header file of ambralsfor.c
Following is the functional form of the forward mode ambrals for you to
incorporate into your code.
float forward(geom_t geom, param_t params);
where geom has members:
geom.szen Solar Zenith
geom.vzen View Zenith
geom.relaz Relative Azimuth
and params has members:
params.iso Isotropic BRDF parameter
params.vol volumetric BRDF parameter
params.geo geometric BRDF parameter
Angles in floating point degrees, BRDF parameters are simple floats.
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/* a simple example of how to use ambrals froward function */
#include "ambralsfor.c"
#include <stdio.h>
main()
{
geom_t geom;
param_t params;
float ref; /* save bidirectional reflectance */
/* set bi-directional observation geometry parameters */
/* which will be provided by you in whatever input format */
/* you prefer --- in this single pixel example they are */
/* just hardcoded */
geom.szen=30.0;
geom.vzen=45.0;
geom.relaz=120.0;
/* set the three weights of Ambrals model */
/* which will be provided by us as a flat */
/* cartesian lat/lon file of floats for each /*
/* ROI ----- in this example they are just hardcoded */
params.iso=0.2;
params.vol=0.1;
params.geo=0.05;
ref=forward(geom,params); /* call ambrals forward model */
printf("%f\n",ref);
}
SAMPLE CODE
one_ref.c: given three parameters and viewing and solar geometries,
compute directional reflectance.
pre_ref_bin.c: given three parameters file (in binary) and viewing
and solar geometries, compute the directional reflectance for the
image.