Gamma LAT: Reference Manual

product

ANSI-C program: product.c

NAME
product - Calculation of product=(data_1 )*(datat_2) betweeen two images.

SYNOPSIS
product <data_1> <data_2> <product> <width> [bx] [by] [weights_flag]

<pwr1>	(input) data file 1 (float)
<pwr2>	(input) data file 2 (float)
<product_out>	(output) product data_1 * data_2 (float)
<width>	number of samples/row
[bx]	box size in range for averaging (before multiplication, default=5)
[by]	box size in azimuth for averaging (before multiplication, default=bx)
[wgt_flag]	weighting mode: 0: no weighting (default) 1: linearly weighting 2: gaussian weighting

EXAMPLE
product 1352_1610.pwr1 1352_1610.pwr2 1352_1610.product 2500 15 15 1

In the selected example both images are averaged using a 15 x 15 pixels window before the product between the averaged images 1352_1610.pwr1/1352_1610.pwr2 is calculated. An increase of the backscattering between image 1352_1610.pwr1 and 1352_1610.pwr2 results in products smaller than 1.0.

DESCRIPTION
product estimates the product between two backscatter intensity images. Due to the speckle noise of SAR images it is very important to first sufficiently filter the individual images before calculation of the product. The program product does this filtering using an running average filter with userdefined filter size and optional weighting function.
The input and the output data are binary files of type float.
The size of the window used for the filtering and the weighting function to apply may be selected. For weights_flag=0 no weighting function is applied, i.e. all filter coefficients are set to 1. For weights_flag=1 a linear weighting function is applied, i.e. the filter coefficients decrease linearly with inclreasing distance to the center of the filter window. For weights_flag=2 a Gaussian weighting function is applied, i.e. the filter coefficients decrease with increasing distance to the center of the filter window following a Gauss function.

SEE ALSO
typedef_ISP.h .