<html><!-- Created using the cpp_pretty_printer from the dlib C++ library. See http://dlib.net for updates. --><head><title>dlib C++ Library - image_ex.cpp</title></head><body bgcolor='white'><pre> <font color='#009900'>// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt </font><font color='#009900'>/* 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. */</font> <font color='#0000FF'>#include</font> <font color='#5555FF'><</font>dlib<font color='#5555FF'>/</font>gui_widgets.h<font color='#5555FF'>></font> <font color='#0000FF'>#include</font> <font color='#5555FF'><</font>dlib<font color='#5555FF'>/</font>image_io.h<font color='#5555FF'>></font> <font color='#0000FF'>#include</font> <font color='#5555FF'><</font>dlib<font color='#5555FF'>/</font>image_transforms.h<font color='#5555FF'>></font> <font color='#0000FF'>#include</font> <font color='#5555FF'><</font>fstream<font color='#5555FF'>></font> <font color='#0000FF'>using</font> <font color='#0000FF'>namespace</font> std; <font color='#0000FF'>using</font> <font color='#0000FF'>namespace</font> dlib; <font color='#009900'>// ---------------------------------------------------------------------------- </font> <font color='#0000FF'><u>int</u></font> <b><a name='main'></a>main</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font> argc, <font color='#0000FF'><u>char</u></font><font color='#5555FF'>*</font><font color='#5555FF'>*</font> argv<font face='Lucida Console'>)</font> <b>{</b> <font color='#0000FF'>try</font> <b>{</b> <font color='#009900'>// make sure the user entered an argument to this program </font> <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>argc <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>2</font><font face='Lucida Console'>)</font> <b>{</b> cout <font color='#5555FF'><</font><font color='#5555FF'><</font> "<font color='#CC0000'>error, you have to enter a BMP file as an argument to this program</font>" <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; <font color='#0000FF'>return</font> <font color='#979000'>1</font>; <b>}</b> <font color='#009900'>// Here we declare an image object that can store rgb_pixels. Note that in </font> <font color='#009900'>// dlib there is no explicit image object, just a 2D array and </font> <font color='#009900'>// various pixel types. </font> array2d<font color='#5555FF'><</font>rgb_pixel<font color='#5555FF'>></font> img; <font color='#009900'>// Now load the image file into our image. If something is wrong then </font> <font color='#009900'>// load_image() will throw an exception. Also, if you linked with libpng </font> <font color='#009900'>// and libjpeg then load_image() can load PNG and JPEG files in addition </font> <font color='#009900'>// to BMP files. </font> <font color='#BB00BB'>load_image</font><font face='Lucida Console'>(</font>img, argv[<font color='#979000'>1</font>]<font face='Lucida Console'>)</font>; <font color='#009900'>// Now let's use some image functions. First let's blur the image a little. </font> array2d<font color='#5555FF'><</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font color='#5555FF'>></font> blurred_img; <font color='#BB00BB'>gaussian_blur</font><font face='Lucida Console'>(</font>img, blurred_img<font face='Lucida Console'>)</font>; <font color='#009900'>// Now find the horizontal and vertical gradient images. </font> array2d<font color='#5555FF'><</font><font color='#0000FF'><u>short</u></font><font color='#5555FF'>></font> horz_gradient, vert_gradient; array2d<font color='#5555FF'><</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>char</u></font><font color='#5555FF'>></font> edge_image; <font color='#BB00BB'>sobel_edge_detector</font><font face='Lucida Console'>(</font>blurred_img, horz_gradient, vert_gradient<font face='Lucida Console'>)</font>; <font color='#009900'>// now we do the non-maximum edge suppression step so that our edges are nice and thin </font> <font color='#BB00BB'>suppress_non_maximum_edges</font><font face='Lucida Console'>(</font>horz_gradient, vert_gradient, edge_image<font face='Lucida Console'>)</font>; <font color='#009900'>// Now we would like to see what our images look like. So let's use a </font> <font color='#009900'>// window to display them on the screen. (Note that you can zoom into </font> <font color='#009900'>// the window by holding CTRL and scrolling the mouse wheel) </font> image_window <font color='#BB00BB'>my_window</font><font face='Lucida Console'>(</font>edge_image, "<font color='#CC0000'>Normal Edge Image</font>"<font face='Lucida Console'>)</font>; <font color='#009900'>// We can also easily display the edge_image as a heatmap or using the jet color </font> <font color='#009900'>// scheme like so. </font> image_window <font color='#BB00BB'>win_hot</font><font face='Lucida Console'>(</font><font color='#BB00BB'>heatmap</font><font face='Lucida Console'>(</font>edge_image<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>; image_window <font color='#BB00BB'>win_jet</font><font face='Lucida Console'>(</font><font color='#BB00BB'>jet</font><font face='Lucida Console'>(</font>edge_image<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>; <font color='#009900'>// also make a window to display the original image </font> image_window <font color='#BB00BB'>my_window2</font><font face='Lucida Console'>(</font>img, "<font color='#CC0000'>Original Image</font>"<font face='Lucida Console'>)</font>; <font color='#009900'>// Sometimes you want to get input from the user about which pixels are important </font> <font color='#009900'>// for some task. You can do this easily by trapping user clicks as shown below. </font> <font color='#009900'>// This loop executes every time the user double clicks on some image pixel and it </font> <font color='#009900'>// will terminate once the user closes the window. </font> point p; <font color='#0000FF'>while</font> <font face='Lucida Console'>(</font>my_window.<font color='#BB00BB'>get_next_double_click</font><font face='Lucida Console'>(</font>p<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font> <b>{</b> cout <font color='#5555FF'><</font><font color='#5555FF'><</font> "<font color='#CC0000'>User double clicked on pixel: </font>" <font color='#5555FF'><</font><font color='#5555FF'><</font> p <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; cout <font color='#5555FF'><</font><font color='#5555FF'><</font> "<font color='#CC0000'>edge pixel value at this location is: </font>" <font color='#5555FF'><</font><font color='#5555FF'><</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font>edge_image[p.<font color='#BB00BB'>y</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>][p.<font color='#BB00BB'>x</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>] <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; <b>}</b> <font color='#009900'>// wait until the user closes the windows before we let the program </font> <font color='#009900'>// terminate. </font> win_hot.<font color='#BB00BB'>wait_until_closed</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; my_window2.<font color='#BB00BB'>wait_until_closed</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <font color='#009900'>// Finally, note that you can access the elements of an image using the normal [row][column] </font> <font color='#009900'>// operator like so: </font> cout <font color='#5555FF'><</font><font color='#5555FF'><</font> horz_gradient[<font color='#979000'>0</font>][<font color='#979000'>3</font>] <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; cout <font color='#5555FF'><</font><font color='#5555FF'><</font> "<font color='#CC0000'>number of rows in image: </font>" <font color='#5555FF'><</font><font color='#5555FF'><</font> horz_gradient.<font color='#BB00BB'>nr</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; cout <font color='#5555FF'><</font><font color='#5555FF'><</font> "<font color='#CC0000'>number of columns in image: </font>" <font color='#5555FF'><</font><font color='#5555FF'><</font> horz_gradient.<font color='#BB00BB'>nc</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; <b>}</b> <font color='#0000FF'>catch</font> <font face='Lucida Console'>(</font>exception<font color='#5555FF'>&</font> e<font face='Lucida Console'>)</font> <b>{</b> cout <font color='#5555FF'><</font><font color='#5555FF'><</font> "<font color='#CC0000'>exception thrown: </font>" <font color='#5555FF'><</font><font color='#5555FF'><</font> e.<font color='#BB00BB'>what</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font color='#5555FF'><</font><font color='#5555FF'><</font> endl; <b>}</b> <b>}</b> <font color='#009900'>// ---------------------------------------------------------------------------- </font> </pre></body></html>