mirror of https://github.com/davisking/dlib.git
107 lines
4.0 KiB
C++
107 lines
4.0 KiB
C++
// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
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/*
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This is a simple example illustrating the use of the get_surf_points()
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function. It pulls out the first 100 SURF points from an input image
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and displays them on the screen as an overlay on the image.
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For a description of the SURF algorithm you should consult the following
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papers:
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This is the original paper which introduced the algorithm:
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SURF: Speeded Up Robust Features
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By Herbert Bay, Tinne Tuytelaars, and Luc Van Gool
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This paper provides a nice detailed overview of how the algorithm works:
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Notes on the OpenSURF Library by Christopher Evans
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*/
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#include "dlib/gui_widgets.h"
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#include "dlib/image_io.h"
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#include "dlib/image_keypoint.h"
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#include <fstream>
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using namespace std;
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using namespace dlib;
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// ----------------------------------------------------------------------------
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int main(int argc, char** argv)
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{
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try
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{
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// make sure the user entered an argument to this program
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if (argc != 2)
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{
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cout << "error, you have to enter a BMP file as an argument to this program" << endl;
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return 1;
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}
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// Here we open the image file. Note that when you open a binary file with
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// the C++ ifstream you must supply the ios::binary flag.
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ifstream fin(argv[1],ios::binary);
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if (!fin)
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{
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cout << "error, can't find " << argv[1] << endl;
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return 1;
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}
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// Here we declare an image object that can store rgb_pixels. Note that in
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// dlib there is no explicit image object, just a 2D array and
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// various pixel types.
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array2d<rgb_pixel>::kernel_1a img;
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// now load the bmp file into our image. If the file isn't really a BMP
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// or is corrupted then load_bmp() will throw an exception.
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load_bmp(img, fin);
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// get the 100 strongest SURF points from the image
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std::vector<surf_point> sp = get_surf_points(img, 100);
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// create a window to display the input image and the SURF boxes
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image_window my_window(img);
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// Now lets draw some rectangles on top of the image so we can see where
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// SURF found its points.
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for (unsigned long i = 0; i < sp.size(); ++i)
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{
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// Pull out the info from the SURF point relevant to figuring out
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// where its rotated box should be.
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const unsigned long box_size = static_cast<unsigned long>(sp[i].p.scale*20);
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const double ang = sp[i].angle;
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const point center(sp[i].p.center);
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rectangle rect = centered_rect(center, box_size, box_size);
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// Rotate the 4 corners of the rectangle
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const point p1 = rotate_point(center, rect.tl_corner(), ang);
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const point p2 = rotate_point(center, rect.tr_corner(), ang);
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const point p3 = rotate_point(center, rect.bl_corner(), ang);
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const point p4 = rotate_point(center, rect.br_corner(), ang);
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// Draw the sides of the box as red lines
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my_window.add_overlay(image_window::overlay_line(p1, p2, rgb_pixel(255,0,0)));
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my_window.add_overlay(image_window::overlay_line(p1, p3, rgb_pixel(255,0,0)));
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my_window.add_overlay(image_window::overlay_line(p4, p2, rgb_pixel(255,0,0)));
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my_window.add_overlay(image_window::overlay_line(p4, p3, rgb_pixel(255,0,0)));
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// Draw a line from the center to the top side so we can see how the box is oriented.
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// Also make this line green.
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my_window.add_overlay(image_window::overlay_line(center, (p1+p2)/2, rgb_pixel(0,255,0)));
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}
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// wait until the user closes the window before we let the program
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// terminate.
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my_window.wait_until_closed();
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}
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catch (exception& e)
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{
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cout << "exception thrown: " << e.what() << endl;
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}
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}
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// ----------------------------------------------------------------------------
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