OpenCV2马拉松第13圈——模版匹配

1. 遍历图像的所有点
2. 对于一个点(m,n),计算square error.也就是遍历模版图像的长和高，计算sum( (src(m+x,n+y)-template(x,y))^2 )
3. 遍历完后，就有了一个和原图大小相等的square error(不考虑边缘)矩阵，然后取出值最小的那个位置

double minVal; double maxVal; Point minLoc; Point maxLoc;

minMaxLoc( image, &minVal, &maxVal, &minLoc, &maxLoc, Mat() );

the function calls as arguments:

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;

Mat img; Mat templ; Mat result;
const char* image_window = "Source Image";
const char* result_window = "Result window";

int match_method;
int max_Trackbar = 5;

void MatchingMethod( int, void* );

int main( int, char** argv )
{
  /// Load image and template
  img = imread( argv[1], 1 );
  templ = imread( argv[2], 1 );

  /// Create windows
  namedWindow( image_window, CV_WINDOW_AUTOSIZE );
  namedWindow( result_window, CV_WINDOW_AUTOSIZE );

  /// Create Trackbar
  const char* trackbar_label = "Method: \n 0: SQDIFF \n 1: SQDIFF NORMED \n 2: TM CCORR \n 3: TM CCORR NORMED \n 4: TM COEFF \n 5: TM COEFF NORMED";
  createTrackbar( trackbar_label, image_window, &match_method, max_Trackbar, MatchingMethod );

  MatchingMethod( 0, 0 );

  waitKey(0);
  return 0;
}

void MatchingMethod( int, void* )
{
  Mat img_display;
  img.copyTo( img_display );

  //重要，调用模版匹配再进行归一化
  matchTemplate( img, templ, result, match_method );
  normalize( result, result, 0, 1, NORM_MINMAX);


  double minVal; double maxVal; Point minLoc; Point maxLoc;
  Point matchLoc;
  //找到最大最小点
  minMaxLoc( result, &minVal, &maxVal, &minLoc, &maxLoc, Mat() );


  //根据我前面讲的，分方法取最大还是最小值
  if( match_method  == CV_TM_SQDIFF || match_method == CV_TM_SQDIFF_NORMED )
    { matchLoc = minLoc; }
  else
    { matchLoc = maxLoc; }

  //画上矩形框框
  rectangle( img_display, matchLoc, Point( matchLoc.x + templ.cols , matchLoc.y + templ.rows ), Scalar::all(0), 2, 8, 0 );
  rectangle( result, matchLoc, Point( matchLoc.x + templ.cols , matchLoc.y + templ.rows ), Scalar::all(0), 2, 8, 0 );

  imshow( image_window, img_display );
  imshow( result_window, result );

  return;
}