dlib/examples/image_ex.cpp

87 lines
2.9 KiB
C++

// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
/*
This is an example illustrating the use of the GUI API as well as some
aspects of image manipulation from the dlib C++ Library.
This is a pretty simple example. It takes a BMP file on the command line
and opens it up, runs a simple edge detection algorithm on it, and
displays the results on the screen.
*/
#include <dlib/gui_widgets.h>
#include <dlib/image_io.h>
#include <dlib/image_transforms.h>
#include <fstream>
using namespace std;
using namespace dlib;
// ----------------------------------------------------------------------------
int main(int argc, char** argv)
{
try
{
// make sure the user entered an argument to this program
if (argc != 2)
{
cout << "error, you have to enter a BMP file as an argument to this program" << endl;
return 1;
}
// Here we declare an image object that can store rgb_pixels. Note that in
// dlib there is no explicit image object, just a 2D array and
// various pixel types.
array2d<rgb_pixel> img;
// Now load the image file into our image. If something is wrong then
// load_image() will throw an exception. Also, if you linked with libpng
// and libjpeg then load_image() can load PNG and JPEG files in addition
// to BMP files.
load_image(img, argv[1]);
// Now lets use some image functions. First lets blur the image a little.
array2d<unsigned char> blurred_img;
gaussian_blur(img, blurred_img);
// Now find the horizontal and vertical gradient images.
array2d<short> horz_gradient, vert_gradient;
array2d<unsigned char> edge_image;
sobel_edge_detector(blurred_img, horz_gradient, vert_gradient);
// now we do the non-maximum edge suppression step so that our edges are nice and thin
suppress_non_maximum_edges(horz_gradient, vert_gradient, edge_image);
// Now we would like to see what our images look like. So lets use a
// window to display them on the screen. (Note that you can zoom into
// the window by holding CTRL and scrolling the mouse wheel)
image_window my_window(edge_image);
// We can also easily display the edge_image as a heatmap like so.
image_window win_hot(heatmap(edge_image, 255));
win_hot.set_title("heatmap version of edge image");
// also make a window to display the original image
image_window my_window2(img);
// wait until the user closes the windows before we let the program
// terminate.
my_window.wait_until_closed();
win_hot.wait_until_closed();
my_window2.wait_until_closed();
}
catch (exception& e)
{
cout << "exception thrown: " << e.what() << endl;
}
}
// ----------------------------------------------------------------------------