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  • Committer: Paparazzi buildbot
  • Date: 2016-05-18 15:00:29 UTC
  • Revision ID: felix.ruess+docbot@gmail.com-20160518150029-e8lgzi5kvb4p7un9
Manual import commit 4b8bbb730080dac23cf816b98908dacfabe2a8ec from v5.0 branch.

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sw/ext/opencv_bebop/opencv/doc/tutorials/features2d/trackingmotion/good_features_to_track/good_features_to_track.markdown
 
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Shi-Tomasi corner detector {#tutorial_good_features_to_track}
 
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==========================
 
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Goal
 
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----
 
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In this tutorial you will learn how to:
 
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-   Use the function @ref cv::goodFeaturesToTrack to detect corners using the Shi-Tomasi method.
 
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Theory
 
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------
 
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Code
 
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----
 
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This tutorial code's is shown lines below. You can also download it from
 
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[here](https://github.com/Itseez/opencv/tree/master/samples/cpp/tutorial_code/TrackingMotion/goodFeaturesToTrack_Demo.cpp)
 
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@code{.cpp}
 
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#include "opencv2/highgui.hpp"
 
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#include "opencv2/imgproc.hpp"
 
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#include <iostream>
 
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#include <stdio.h>
 
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#include <stdlib.h>
 
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using namespace cv;
 
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using namespace std;
 
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/// Global variables
 
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Mat src, src_gray;
 
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int maxCorners = 23;
 
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int maxTrackbar = 100;
 
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RNG rng(12345);
 
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char* source_window = "Image";
 
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/// Function header
 
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void goodFeaturesToTrack_Demo( int, void* );
 
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/*
 
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 * @function main
 
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 */
 
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int main( int argc, char** argv )
 
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{
 
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  /// Load source image and convert it to gray
 
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  src = imread( argv[1], 1 );
 
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  cvtColor( src, src_gray, COLOR_BGR2GRAY );
 
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  /// Create Window
 
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  namedWindow( source_window, WINDOW_AUTOSIZE );
 
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  /// Create Trackbar to set the number of corners
 
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  createTrackbar( "Max  corners:", source_window, &maxCorners, maxTrackbar, goodFeaturesToTrack_Demo );
 
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  imshow( source_window, src );
 
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  goodFeaturesToTrack_Demo( 0, 0 );
 
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  waitKey(0);
 
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  return(0);
 
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}
 
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/*
 
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 * @function goodFeaturesToTrack_Demo.cpp
 
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 * @brief Apply Shi-Tomasi corner detector
 
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 */
 
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void goodFeaturesToTrack_Demo( int, void* )
 
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{
 
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  if( maxCorners < 1 ) { maxCorners = 1; }
 
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  /// Parameters for Shi-Tomasi algorithm
 
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  vector<Point2f> corners;
 
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  double qualityLevel = 0.01;
 
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  double minDistance = 10;
 
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  int blockSize = 3;
 
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  bool useHarrisDetector = false;
 
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  double k = 0.04;
 
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  /// Copy the source image
 
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  Mat copy;
 
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  copy = src.clone();
 
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  /// Apply corner detection
 
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  goodFeaturesToTrack( src_gray,
 
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               corners,
 
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               maxCorners,
 
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               qualityLevel,
 
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               minDistance,
 
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               Mat(),
 
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               blockSize,
 
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               useHarrisDetector,
 
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               k );
 
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  /// Draw corners detected
 
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  cout<<"** Number of corners detected: "<<corners.size()<<endl;
 
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  int r = 4;
 
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  for( size_t i = 0; i < corners.size(); i++ )
 
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     { circle( copy, corners[i], r, Scalar(rng.uniform(0,255), rng.uniform(0,255),
 
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              rng.uniform(0,255)), -1, 8, 0 ); }
 
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  /// Show what you got
 
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  namedWindow( source_window, WINDOW_AUTOSIZE );
 
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  imshow( source_window, copy );
 
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}
 
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@endcode
 
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Explanation
 
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-----------
 
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Result
 
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------
 
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![](images/Feature_Detection_Result_a.jpg)