opencv学习之路（25）、轮廓查找与绘制（四）——正外接矩形

一、简介

二、外接矩形的查找绘制

 #include "opencv2/opencv.hpp"
 using namespace cv;
 void main()
 {
     //外接矩形的查找绘制
     Mat srcImg =imread("E://12.jpg");
     imshow("src",srcImg);
     Mat dstImg = srcImg.clone();  //原图备份
     cvtColor(srcImg, srcImg, CV_BGR2GRAY); //转为灰度图
     threshold(srcImg, srcImg, , , CV_THRESH_BINARY); //二值化

     vector<vector<Point>> contours;
     vector<Vec4i> hierarcy;
     findContours(srcImg, contours, hierarcy, CV_RETR_EXTERNAL, CHAIN_APPROX_NONE); //查找轮廓
     vector<Rect> boundRect(contours.size()); //定义外接矩形集合
     //drawContours(dstImg, contours, -1, Scalar(0, 0, 255), 2, 8);  //绘制轮廓
     int x0=, y0=, w0=, h0=;
     for(int i=; i<contours.size(); i++)
     {
         boundRect[i] = boundingRect((Mat)contours[i]); //查找每个轮廓的外接矩形
         drawContours(dstImg, contours, i, Scalar(, , ), , );  //绘制轮廓
         x0 = boundRect[i].x;  //获得第i个外接矩形的左上角的x坐标
         y0 = boundRect[i].y; //获得第i个外接矩形的左上角的y坐标
         w0 = boundRect[i].width; //获得第i个外接矩形的宽度
         h0 = boundRect[i].height; //获得第i个外接矩形的高度
         rectangle(dstImg, Point(x0, y0), Point(x0+w0, y0+h0), Scalar(, , ), , ); //绘制第i个外接矩形
     }
     imshow("boundRect", dstImg);
     waitKey();
 }

三、分割硬币轮廓并计数

 #include "opencv2/opencv.hpp"
 #include<iostream>
 using namespace cv;
 using namespace std;
 void main()
 {
     //分割硬币轮廓
     Mat srcImg =imread("E://33.png");
     imshow("src", srcImg);
     Mat dstImg = srcImg.clone();  //原图备份
     cvtColor(srcImg, srcImg, CV_BGR2GRAY); //转为灰度图
     threshold(srcImg, srcImg, , , CV_THRESH_BINARY); //二值化
     Mat element = getStructuringElement(MORPH_RECT, Size(, ), Point(-, -)); //获得结构元素
     dilate(srcImg, srcImg, element); //膨胀操作
     imshow("dilate",srcImg);

     vector<vector<Point>> contours;
     vector<Vec4i> hierarcy;
     findContours(srcImg, contours, hierarcy, CV_RETR_EXTERNAL, CHAIN_APPROX_NONE); //查找轮廓
     vector<Rect> boundRect(contours.size()); //定义外接矩形集合
     int x0=, y0=, w0=, h0=,num=;
     for(int i=; i<contours.size(); i++)
     {
         boundRect[i] = boundingRect((Mat)contours[i]); //查找每个轮廓的外接矩形
         drawContours(dstImg, contours, i, Scalar(, , ), , );  //绘制轮廓
         x0 = boundRect[i].x;
         y0 = boundRect[i].y;
         w0 = boundRect[i].width;
         h0 = boundRect[i].height;
         if(w0> && h0>)//筛选
         {
             rectangle(dstImg, Point(x0, y0), Point(x0+w0, y0+h0), Scalar(, , ), , ); //绘制第i个外接矩形
             num++;
         }
     }
     cout<<"硬币数量："<<num;
     imshow("boundRect", dstImg);
     waitKey();
 }

四、简单车牌字符分隔

 #include "opencv2/opencv.hpp"
 using namespace cv;
 void main()
 {
     //---简单车牌字符分隔
     Mat srcImg =imread("E://Car2.jpg");
     Mat dstImg = srcImg.clone();  //原图备份
     medianBlur(srcImg, srcImg, );  //中值滤波
     cvtColor(srcImg, srcImg, CV_BGR2GRAY); //转为灰度图
     threshold(srcImg, srcImg, , , CV_THRESH_BINARY); //二值化
     imshow("threshold", srcImg);
     imwrite("F://car0.jpg", srcImg);

     vector<vector<Point>> contours;
     vector<Vec4i> hierarcy;
     findContours(srcImg, contours, hierarcy, CV_RETR_TREE, CHAIN_APPROX_NONE); //查找所有轮廓
     vector<Rect> boundRect(contours.size()); //定义外接矩形集合
     int x0=, y0=, w0=, h0=;
     for(int i=; i<contours.size(); i++)
     {
         boundRect[i] = boundingRect((Mat)contours[i]); //查找每个轮廓的外接矩形
         x0 = boundRect[i].x;
         y0 = boundRect[i].y;
         w0 = boundRect[i].width;
         h0 = boundRect[i].height;
         if(w0>srcImg.cols/ && w0<srcImg.cols/ && h0>srcImg.rows/ && h0<srcImg.rows*/)
         {
             char pic_name[];
             sprintf(pic_name, "F:\\%d.bmp", i);
             Mat ROI = dstImg(Rect(x0, y0, w0, h0));
             imwrite(pic_name, ROI);
             rectangle(dstImg, Point(x0, y0), Point(x0+w0, y0+h0), Scalar(, , ), , ); //绘制第i个外接矩形
         }
     }
     imshow("boundRect", dstImg);
     waitKey();
 }