用图像分割之最大连通域算法得到最大轮廓矩形框，再使用grabcut分割：

用图像分割之最大连通域算法得到最大轮廓矩形框，再使用grabcut分割：

#include<opencv2\opencv.hpp>  
#include<cmath>  
  
using namespace cv;  
using namespace std;  
  
int main()  
{  
    Mat srcImage = imread( "test_image.png" ,0);  
    if( !srcImage.data )  
    {  
        cout << "读取失败" << endl;  
        return 0;  
    }  
namedWindow( "原始图", CV_WINDOW_NORMAL ); 
    imshow( "原始图" , srcImage );  
  Mat dstImage;
    // threshold只针对二值化图像  
   threshold( srcImage , dstImage ,228.0 , 255.0 ,CV_THRESH_BINARY|CV_THRESH_OTSU );
   namedWindow( "dstImage", CV_WINDOW_NORMAL ); 
    imshow( "dstImage" , dstImage );  
  //threshold(srcImage, srcImage,27, 255, CV_THRESH_BINARY);


    vector<vector<Point>> contours;  
    vector<Vec4i> hierarchy;  
  
    findContours( dstImage , contours , hierarchy , CV_RETR_CCOMP , CV_CHAIN_APPROX_SIMPLE );  
  
    vector<Point> maxcontours ;   //最大轮廓  
    double maxArea = 0;  
  
//  vector<vector<Point>>::const_iterator itContours = contours.begin();  
    for( size_t i = 0; i < contours.size();i++ )  
    {  
        double area = contourArea( contours[i] );  
        if( area > maxArea )  
        {  
            maxArea = area;  
            maxcontours = contours[i];  
        }  
    }  
  
    Rect maxRect = boundingRect( maxcontours );  //查找矩形框  
  
    Mat result1 , result2;  
  
    dstImage.copyTo( result1 );  
    dstImage.copyTo( result2 );  
  
    for( size_t i = 0; i < contours.size(); i++ )  
    {  
        Rect r = boundingRect( contours[i] );  
        rectangle( result1 , r , Scalar( 255 ) );  
    }  
namedWindow( "all regions", CV_WINDOW_NORMAL ); 
    imshow( "all regions" , result1 );  
    waitKey(100);  
  
    rectangle( result2 , maxRect , Scalar(255 ) );  
namedWindow( "largest regions", CV_WINDOW_NORMAL ); 
    imshow( "largest regions" , result2 );  
    waitKey(100);


Mat srcMarks,temp,img0;
    temp = imread("test_image.png"); 
//namedWindow("原图",CV_WINDOW_NORMAL);
   // imshow("原图", temp); 
//resize(temp,img,Size(temp.cols/2,temp.rows/2),0,0,INTER_LINEAR);
// namedWindow("resize",CV_WINDOW_NORMAL);
// imshow("resize", img); 
img0 = temp.clone();
int cols=temp.cols, rows=temp.rows;
temp.copyTo(srcMarks);
cv::rectangle(srcMarks, maxRect, cv::Scalar(255, 0, 0),1,1,0);



Mat result; // 4种可能结果  
    Mat bgModel, fgModel; // 背景/前景 
grabCut(srcMarks, result, maxRect, bgModel, fgModel, 5, GC_INIT_WITH_RECT);  
            compare(result,GC_PR_FGD,result,CMP_EQ);//得到前景mask  
            Mat foreground(temp.size(),CV_8UC3,Scalar::all(255));  
            img0.copyTo(foreground,result); 
namedWindow("grabcut",CV_WINDOW_NORMAL);
            imshow("grabcut",foreground);

     waitKey();      
}