1.目的
(1)使用OpenCV函數 boundingRect 來計算包圍輪廓的矩形框.
(2)使用OpenCV函數 minEnclosingCircle 來計算完全包圍已有輪廓最小圓.
2.部分代碼解釋
(1)approxPolyDP
/*approxPolyDP參數解釋
contours[i]:輸入的二維輪廓,以點集表示
contours_poly[i]:輸出近似的多邊形輪廓,以點集表示
epsilon:估算精度,表示輸入和輸出的最小距離
closed:輸出輪廓是否閉合,true表示閉合,false表示不閉合
*/
approxPolyDP(contours[i], contours_poly[i], 3, true);
(2)boundingRect
/*
boundingRect參數解釋
contours_poly[i]:輸入的二維輪廓,以點集表示
返回值:一個描述矩形邊框的實例,tl()表示左上角的座標點,br()表示右下角的座標點
*/
boundRec[i] = boundingRect(contours_poly[i]);
(3)minEnclosingCircle
/*
minEnclosingCircle參數解釋
contours_poly[i]:輸入的二維輪廓, 以點集表示
center[i]:包圍二維輪廓的最小圓的圓心
radius[i]:圓的半徑
*/
minEnclosingCircle(contours_poly[i], center[i], radius[i]);
3.完整代碼
(1)CommonInclude.h
#ifndef COMMON_INCLUDE
#define COMMON_INCLUDE
#include<iostream>
#include<opencv2/core/core.hpp>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
using namespace std;
using namespace cv;
#endif
(2)Bounding.cpp
#include"CommonInclude.h"
int thresh = 50;
int max_thresh = 85;
Mat src, src_gray, src_blur, dst;
RNG rng(12345);
char windowName[] = "Bounding";
void ThreshCallback(int,void*){
vector< vector<Point> > contours;
vector< Vec4i > hirerachy;
//canny邊緣檢測
Canny(src_gray, dst, thresh, max_thresh, 3);
//尋找輪廓
findContours(dst, contours, hirerachy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0,0));
cout << contours.size() << endl;
vector< vector<Point> > contours_poly(contours.size());
vector< Rect > boundRec(contours.size());
vector< Point2f > center(contours.size());
vector< float > radius(contours.size());
for(int i=0; i<contours.size(); i++){
/*approxPolyDP參數解釋
contours[i]:輸入的二維輪廓,以點集表示
contours_poly[i]:輸出近似的多邊形輪廓,以點集表示
epsilon:估算精度,表示輸入和輸出的最小距離
closed:輸出輪廓是否閉合,true表示閉合,false表示不閉合
*/
approxPolyDP(contours[i], contours_poly[i], 3, true);
//獲取輪廓的矩形邊界框
/*
boundingRect參數解釋
contours_poly[i]:輸入的二維輪廓,以點集表示
返回值:一個描述矩形邊框的實例,tl()表示左上角的座標點,br()表示右下角的座標點
*/
boundRec[i] = boundingRect(contours_poly[i]);
//獲取輪廓的圓形邊界
/*
minEnclosingCircle參數解釋
contours_poly[i]:輸入的二維輪廓, 以點集表示
center[i]:包圍二維輪廓的最小圓的圓心
radius[i]:圓的半徑
*/
minEnclosingCircle(contours_poly[i], center[i], radius[i]);
}
//繪製輪廓
Mat drawing = Mat::zeros(dst.size(), CV_8UC3);
for(int i=0; i<contours.size(); i++){
Scalar color = Scalar(rng.uniform(0,255), rng.uniform(0,255), rng.uniform(0,255));
drawContours(drawing, contours_poly, i, color, 2, 8);
rectangle(drawing, boundRec[i].tl(), boundRec[i].br(), color, 2, 8);
circle(drawing, center[i], radius[i], color, 2, 8);
}
imshow(windowName, drawing);
}
int main(int argc, char** argv){
if(argc < 2){
cout << "more parameters are required!!!" << endl;
return(-1);
}
namedWindow(windowName, CV_WINDOW_AUTOSIZE);
src = imread(argv[1]);
//高斯平滑
GaussianBlur(src, src_blur, Size(3,3), 0, 0);
//轉化成灰度圖像
cvtColor(src_blur, src_gray, CV_BGR2GRAY);
createTrackbar("Thesh:", windowName, &thresh, max_thresh, ThreshCallback);
ThreshCallback(0,0);
waitKey(0);
return(0);
}