opencv学习之路（23）、轮廓查找与绘制（二）——访问轮廓每个点

一、简介

二、画出每个轮廓的每个点

#include "opencv2/opencv.hpp"
using namespace cv;

void main()
{
    Mat src=imread("E://22.jpg");
    Mat temp=src.clone();
    //转灰度图，二值化
    cvtColor(src,src,CV_BGR2GRAY);
    threshold(src,src,100,255,THRESH_BINARY);
    imshow("thres",src);
    //查找并绘制轮廓
    vector<vector<Point>>contours;
    vector<Vec4i>hierarcy;
    findContours(src,contours,hierarcy,CV_RETR_TREE,CV_LINK_RUNS);
    /*drawContours(temp,contours,-1,Scalar(0,255,0),2,8);    绘制并显示所有轮廓
    imshow("contours",temp);*/

    //绘制轮廓的每一个点
    for(int i=0; i<contours.size(); i++){
        for(int j=0; j<contours[i].size(); j++){
            circle(temp,Point(contours[i][j].x,contours[i][j].y),3,Scalar(0,255,0),2,8); 
        }
    }
    imshow("contours",temp);
    waitKey(0);
}

轮廓太密集了，稍微改改参数

　　　　 for(int j=0; j<contours[i].size(); j+=15){
            circle(temp,Point(contours[i][j].x,contours[i][j].y),3,Scalar(0,255,0),2,8); 
        }

稍微改改，有另一种效果（动态射线）

for(int i=0; i<contours.size(); i++){
        for(int j=0; j<contours[i].size(); j+=15){
            circle(temp,Point(contours[i][j].x,contours[i][j].y),3,Scalar(0,255,0),2,8); 
            line(temp,Point(10,10),Point(contours[i][j].x,contours[i][j].y), Scalar(0, 0, 255), 1, 8);
            waitKey(100);
            imshow("contours", temp);
        }
    }

改改又是一种效果

三、孔洞填充

#include "opencv2/opencv.hpp"
using namespace cv;

void main()
{
    Mat src=imread("E://33.jpg");
    Mat temp=src.clone();
    //转灰度图，二值化
    cvtColor(src,src,CV_BGR2GRAY);
    threshold(src,src,100,255,THRESH_BINARY);
    imshow("thres",src);
    //查找并绘制轮廓
    vector<vector<Point>>contours;
    vector<Vec4i>hierarcy;
    findContours(src,contours,hierarcy,CV_RETR_EXTERNAL,CV_CHAIN_APPROX_NONE);
    
    ///孔洞填充
    findContours(src, contours, hierarcy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE); //查找轮廓
    drawContours(temp, contours, -1, Scalar(0, 255, 0), -1, 8); //绘制轮廓
    imshow("contours",temp);
    waitKey(0);
}

稍微改改