?1、convexHull函數(shù)

函數(shù)的作用：

計算出圖像的凸包，這里是根據(jù)圖像的輪廓點，通過函數(shù)?convexHull 轉(zhuǎn)化成凸包的點點的坐標，

從而畫出圖像的凸包。

2、?convexHull函數(shù)的調(diào)用形式

C++:?void?convexHull(InputArray?points, OutputArray?hull, bool?clockwise=false, bool?returnPoints=true?)

參數(shù)詳解：

InputArray?points：得到的點集，一般是用圖像輪廓函數(shù)求得的輪廓點

OutputArray?hull：輸出的是凸包的二維xy點的坐標值，針對每一個輪廓形成的

?bool?clockwise=false：表示凸包的方向，順時針或者逆時針

bool?returnPoints=true：表示返回點還是點地址的索引，

3、opencv代碼

#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <iostream>#include <stdio.h>#include <stdlib.h>using namespace cv;using namespace std;Mat src; Mat src_gray;int thresh = 100;int max_thresh = 255;RNG rng(12345);/// Function headervoid thresh_callback(int, void* );/** @function main */ int main( int argc, char** argv ){/// 加載源圖像src = imread( argv[1], 1 );/// 轉(zhuǎn)成灰度圖并進行模糊降噪cvtColor( src, src_gray, CV_BGR2GRAY );blur( src_gray, src_gray, Size(3,3) );/// 創(chuàng)建窗體char* source_window = "Source";namedWindow( source_window, CV_WINDOW_AUTOSIZE );imshow( source_window, src );createTrackbar( " Threshold:", "Source", &thresh, max_thresh, thresh_callback );thresh_callback( 0, 0 );waitKey(0);return(0);}/** @function thresh_callback */void thresh_callback(int, void* ){Mat src_copy = src.clone();Mat threshold_output;vector<vector<Point> > contours;vector<Vec4i> hierarchy;/// 對圖像進行二值化threshold( src_gray, threshold_output, thresh, 255, THRESH_BINARY );/// 尋找輪廓findContours( threshold_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );/// 對每個輪廓計算其凸包vector<vector<Point> >hull( contours.size() );for( int i = 0; i < contours.size(); i++ ){ convexHull( Mat(contours[i]), hull[i], false ); }/// 繪出輪廓及其凸包Mat drawing = Mat::zeros( threshold_output.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, i, color, 1, 8, vector<Vec4i>(), 0, Point() );drawContours( drawing, hull, i, color, 1, 8, vector<Vec4i>(), 0, Point() );}/// 把結(jié)果顯示在窗體namedWindow( "Hull demo", CV_WINDOW_AUTOSIZE );imshow( "Hull demo", drawing );}

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