mirror of
https://github.com/opencv/opencv.git
synced 2024-12-12 15:19:11 +08:00
99 lines
2.6 KiB
ReStructuredText
99 lines
2.6 KiB
ReStructuredText
.. _feature_detection:
|
|
|
|
Feature Detection
|
|
******************
|
|
|
|
Goal
|
|
=====
|
|
|
|
In this tutorial you will learn how to:
|
|
|
|
.. container:: enumeratevisibleitemswithsquare
|
|
|
|
* Use the :feature_detector:`FeatureDetector<>` interface in order to find interest points. Specifically:
|
|
|
|
* Use the :surf_feature_detector:`SurfFeatureDetector<>` and its function :feature_detector_detect:`detect<>` to perform the detection process
|
|
* Use the function :draw_keypoints:`drawKeypoints<>` to draw the detected keypoints
|
|
|
|
|
|
Theory
|
|
======
|
|
|
|
Code
|
|
====
|
|
|
|
This tutorial code's is shown lines below. You can also download it from `here <http://code.opencv.org/projects/opencv/repository/revisions/master/raw/samples/cpp/tutorial_code/features2D/SURF_detector.cpp>`_
|
|
|
|
.. code-block:: cpp
|
|
|
|
#include <stdio.h>
|
|
#include <iostream>
|
|
#include "opencv2/core/core.hpp"
|
|
#include "opencv2/features2d/features2d.hpp"
|
|
#include "opencv2/nonfree/features2d.hpp"
|
|
#include "opencv2/highgui/highgui.hpp"
|
|
#include "opencv2/nonfree/nonfree.hpp"
|
|
|
|
using namespace cv;
|
|
|
|
void readme();
|
|
|
|
/** @function main */
|
|
int main( int argc, char** argv )
|
|
{
|
|
if( argc != 3 )
|
|
{ readme(); return -1; }
|
|
|
|
Mat img_1 = imread( argv[1], CV_LOAD_IMAGE_GRAYSCALE );
|
|
Mat img_2 = imread( argv[2], CV_LOAD_IMAGE_GRAYSCALE );
|
|
|
|
if( !img_1.data || !img_2.data )
|
|
{ std::cout<< " --(!) Error reading images " << std::endl; return -1; }
|
|
|
|
//-- Step 1: Detect the keypoints using SURF Detector
|
|
int minHessian = 400;
|
|
|
|
SurfFeatureDetector detector( minHessian );
|
|
|
|
std::vector<KeyPoint> keypoints_1, keypoints_2;
|
|
|
|
detector.detect( img_1, keypoints_1 );
|
|
detector.detect( img_2, keypoints_2 );
|
|
|
|
//-- Draw keypoints
|
|
Mat img_keypoints_1; Mat img_keypoints_2;
|
|
|
|
drawKeypoints( img_1, keypoints_1, img_keypoints_1, Scalar::all(-1), DrawMatchesFlags::DEFAULT );
|
|
drawKeypoints( img_2, keypoints_2, img_keypoints_2, Scalar::all(-1), DrawMatchesFlags::DEFAULT );
|
|
|
|
//-- Show detected (drawn) keypoints
|
|
imshow("Keypoints 1", img_keypoints_1 );
|
|
imshow("Keypoints 2", img_keypoints_2 );
|
|
|
|
waitKey(0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/** @function readme */
|
|
void readme()
|
|
{ std::cout << " Usage: ./SURF_detector <img1> <img2>" << std::endl; }
|
|
|
|
Explanation
|
|
============
|
|
|
|
Result
|
|
======
|
|
|
|
#. Here is the result of the feature detection applied to the first image:
|
|
|
|
.. image:: images/Feature_Detection_Result_a.jpg
|
|
:align: center
|
|
:height: 125pt
|
|
|
|
#. And here is the result for the second image:
|
|
|
|
.. image:: images/Feature_Detection_Result_b.jpg
|
|
:align: center
|
|
:height: 200pt
|