轮廓匹配

opencv学习之路（28）、轮廓查找与绘制（七）——位置关系及轮廓匹配

一、点与轮廓的距离及位置关系

 1 #include "opencv2/opencv.hpp"
 2 #include <iostream>
 3 using namespace std;
 4 using namespace cv;
 5 
 6 void main()
 7 {
 8     //计算点到轮廓的距离与位置关系
 9     Mat srcImg = imread("E://00.png");
10     imshow("src", srcImg);
11 
12     Mat dstImg = srcImg.clone();
13     cvtColor(srcImg, srcImg, CV_BGR2GRAY);
14     threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY);
15     imshow("threshold", srcImg);
16 
17     //查找轮廓
18     vector<vector<Point>> contours;
19     vector<Vec4i> hierarcy;
20     findContours(srcImg, contours, hierarcy, CV_RETR_TREE, CV_CHAIN_APPROX_NONE);//TREE:提取所有轮廓    NONE：画出轮廓所有点
21     cout << "contours.size()=" << contours.size() << endl;
22     for (int i = 0; i < contours.size(); i++)//遍历每个轮廓
23     {
24         for (int j = 0; j < contours[i].size(); j++)//遍历轮廓每个点
25         {
26             cout << "(" << contours[i][j].x << "," << contours[i][j].y << ")" << endl;
27         }
28     }
29 
30     double a0 = pointPolygonTest(contours[0], Point(3, 3), true);//点到轮廓的最短距离
31     double b0 = pointPolygonTest(contours[0], Point(212, 184), false);//点与轮廓的位置关系：-1表示外部；0表示在轮廓上；1表示轮廓内部
32     cout << "a0=" << a0 << endl;
33     cout << "b0=" << b0 << endl;
34     waitKey(0);
35 }

a0之所以是负数，是因为点在轮廓外部

二、轮廓的矩

轮廓矩的介绍：

http://blog.csdn.net/cp32212116/article/details/38374015 
http://blog.csdn.net/huixingshao/article/details/42060231

 1 #include "opencv2/opencv.hpp"
 2 #include <iostream>
 3 using namespace std;
 4 using namespace cv;
 5 
 6 void main()
 7 {
 8     Mat srcImg = imread("E://00.png");
 9     imshow("src", srcImg);
10 
11     Mat dstImg = srcImg.clone();
12     cvtColor(srcImg, srcImg, CV_BGR2GRAY);
13     threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY);
14     //imshow("threshold", srcImg);
15 
16     vector<vector<Point>> contours;
17     vector<Vec4i> hierarcy;
18     findContours(srcImg, contours, hierarcy, CV_RETR_TREE, CV_CHAIN_APPROX_NONE);
19     cout << "contours.size()=" << contours.size() << endl;
20     Moments moment0 = moments(contours[0], false);
21     cout << moment0.m00<< endl;
22     waitKey(0);
23 }

三、形状匹配--matchShapes()

注意与模板匹配matchTemplate()相区分。形状匹配对于旋转、尺度、位移都能适应。

 1 #include "opencv2/opencv.hpp"
 2 #include <iostream>
 3 #include <iomanip>
 4 using namespace std;
 5 using namespace cv;
 6 
 7 void main()
 8 {
 9     Mat srcImg = imread("1.jpg");  //模板图像
10     imshow("src", srcImg);
11     cvtColor(srcImg, srcImg, CV_BGR2GRAY);
12     threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY);
13     vector<vector<Point>> contours;
14     vector<Vec4i> hierarcy;
15     findContours(srcImg, contours, hierarcy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);
16 
17     Mat srcImg2 = imread("2.jpg");  //待测试图片
18     imshow("src2", srcImg2);
19     Mat dstImg = srcImg2.clone();
20     cvtColor(srcImg2, srcImg2, CV_BGR2GRAY);
21     threshold(srcImg2, srcImg2, 100, 255, CV_THRESH_BINARY);
22     vector<vector<Point>> contours2;
23     vector<Vec4i> hierarcy2;
24     findContours(srcImg2, contours2, hierarcy2, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);
25     while (1)
26     {
27         for (int i = 0; i<contours2.size(); i++)
28         {
29             double matchRate = matchShapes(contours[0], contours2[i], CV_CONTOURS_MATCH_I1, 0.0);//形状匹配:值越小越相似
30             cout << "index=" << i << "---" << setiosflags(ios::fixed) << matchRate << endl;//setiosflags(ios::fixed)是用定点方式表示实数，保留相同位数，相同格式输出
31             if (matchRate <= 0.1)
32                 drawContours(dstImg, contours2, i, Scalar(0, 255, 0), 2, 8);
33             imshow("dst", dstImg);
34             /*char key = waitKey();
35             if (key == 27)
36                 break;*/
37         }
38         break;
39     }
40     waitKey(0);
41 }