1Before anything else, let's look at some example programs. 2 3@section Gradients 4The image processing equivalent of "Hello world": 5@example 6 7#include <vcl_iostream.h> 8#include <vil/vil_load.h> 9#include <vil/vil_save.h> 10#include <vepl/vepl_gradient_mag.h> 11 12int main(int argc, char** argv) 13@{ 14 // The input image: 15 vil_image_view<unsigned char> in = vil_load(argv[1]); 16 17 // The filter: 18 vil_image_view<unsigned char> out = vepl_gradient_mag(in); 19 20 // Write output: 21 vil_save(out, argv[2]); 22 vcl_cout << "Written the gradrient image to " << argv[2] << vcl_endl; 23 24 return 0; 25@} 26@end example 27This example takes one grey-level image, and creates a second whose pixel values are the 28gradient magnitudes of the first. 29