DOWN_UP1 down samples an image and then up samples the result.
SYNOPSIS
function y=down_up1(x);
DESCRIPTION
DOWN_UP1 down samples an image and then up samples the result.
USAGE: y=down_up1(x)
image y is obtained from image x by summing the patches of size 2x2
Author: Ali Mohammad-Djafari
Date: Nov. 4, 2002
Test:
x=rand(6); y=down_up1(x);
