1. 程式人生 > 程式設計 >使用OpenCV去除面積較小的連通域

使用OpenCV去除面積較小的連通域

這是後期補充的部分,和前期的程式碼不太一樣

效果圖

使用OpenCV去除面積較小的連通域

原始碼

//測試
void CCutImageVS2013Dlg::OnBnClickedTestButton1()
{
	vector<vector<Point> > contours;  //輪廓陣列
	vector<Point2d> centers;    //輪廓質心座標 
	vector<vector<Point> >::iterator itr; //輪廓迭代器
	vector<Point2d>::iterator itrc;  //質心座標迭代器
	vector<vector<Point> > con;   //當前輪廓

	double area;
	double minarea = 1000;
	double maxarea = 0;
	Moments mom;       // 輪廓矩
	Mat image,gray,edge,dst;
	image = imread("D:\\66.png");
	cvtColor(image,COLOR_BGR2GRAY);
	Mat rgbImg(gray.size(),CV_8UC3); //建立三通道圖
	blur(gray,Size(3,3));       //模糊去噪
	threshold(edge,200,255,THRESH_BINARY_INV); //二值化處理,黑底白字
	//--------去除較小輪廓,並尋找最大輪廓--------------------------
	findContours(edge,contours,CV_RETR_EXTERNAL,CV_CHAIN_APPROX_SIMPLE); //尋找輪廓
	itr = contours.begin();    //使用迭代器去除噪聲輪廓
	while (itr != contours.end())
	{
		area = contourArea(*itr);  //獲得輪廓面積
		if (area<minarea)    //刪除較小面積的輪廓 
		{
			itr = contours.erase(itr); //itr一旦erase,需要重新賦值
		}
		else
		{
			itr++;
		}
		if (area>maxarea)    //尋找最大輪廓
		{
			maxarea = area;
		}
	}
	dst = Mat::zeros(image.rows,image.cols,CV_8UC3);
	/*繪製連通區域輪廓,計算質心座標*/
	Point2d center;
	itr = contours.begin();
	while (itr != contours.end())
	{
		area = contourArea(*itr);		
		con.push_back(*itr);   //獲取當前輪廓
		if (area == maxarea)
		{
			vector<Rect> boundRect(1); //定義外接矩形集合
			boundRect[0] = boundingRect(Mat(*itr));
			cvtColor(gray,rgbImg,COLOR_GRAY2BGR);
			Rect select;
			select.x = boundRect[0].x;
			select.y = boundRect[0].y;
			select.width = boundRect[0].width;
			select.height = boundRect[0].height;
			rectangle(rgbImg,select,Scalar(0,0),3,2); //用矩形畫矩形窗
			drawContours(dst,con,-1,255),2); //最大面積紅色繪製
		}
		else
			drawContours(dst,Scalar(255,2); //其它面積藍色繪製
		con.pop_back();
		//計算質心
		mom = moments(*itr);
		center.x = (int)(mom.m10 / mom.m00);
		center.y = (int)(mom.m01 / mom.m00);
		centers.push_back(center);
		itr++;
	}
	imshow("rgbImg",rgbImg);
	//imshow("gray",gray);
	//imshow("edge",edge);
	imshow("origin",image);
	imshow("connected_region",dst);
	waitKey(0);
	return;
}

前期做的,方法可能不太一樣

一,先看效果圖

原圖

使用OpenCV去除面積較小的連通域

處理前後圖

使用OpenCV去除面積較小的連通域

二,實現原始碼

//=======函式實現=====================================================================
void RemoveSmallRegion(Mat &Src,Mat &Dst,int AreaLimit,int CheckMode,int NeihborMode)
{
	int RemoveCount = 0;
	//新建一幅標籤影象初始化為0畫素點,為了記錄每個畫素點檢驗狀態的標籤,0代表未檢查,1代表正在檢查,2代表檢查不合格(需要反轉顏色),3代表檢查合格或不需檢查 
	//初始化的影象全部為0,未檢查 
	Mat PointLabel = Mat::zeros(Src.size(),CV_8UC1);
	if (CheckMode == 1)//去除小連通區域的白色點 
	{
		//cout << "去除小連通域.";
		for (int i = 0; i < Src.rows; i++)
		{
			for (int j = 0; j < Src.cols; j++)
			{
				if (Src.at<uchar>(i,j) < 10)
				{
					PointLabel.at<uchar>(i,j) = 3;//將背景黑色點標記為合格,畫素為3 
				}
			}
		}
	}
	else//去除孔洞,黑色點畫素 
	{
		//cout << "去除孔洞";
		for (int i = 0; i < Src.rows; i++)
		{
			for (int j = 0; j < Src.cols; j++)
			{
				if (Src.at<uchar>(i,j) > 10)
				{
					PointLabel.at<uchar>(i,j) = 3;//如果原圖是白色區域,標記為合格,畫素為3 
				}
			}
		}
	}
	vector<Point2i>NeihborPos;//將鄰域壓進容器 
	NeihborPos.push_back(Point2i(-1,0));
	NeihborPos.push_back(Point2i(1,0));
	NeihborPos.push_back(Point2i(0,-1));
	NeihborPos.push_back(Point2i(0,1));
	if (NeihborMode == 1)
	{
		//cout << "Neighbor mode: 8鄰域." << endl;
		NeihborPos.push_back(Point2i(-1,-1));
		NeihborPos.push_back(Point2i(-1,1));
		NeihborPos.push_back(Point2i(1,-1));
		NeihborPos.push_back(Point2i(1,1));
	}
	else int a = 0;//cout << "Neighbor mode: 4鄰域." << endl;
	int NeihborCount = 4 + 4 * NeihborMode;
	int CurrX = 0,CurrY = 0;
	//開始檢測 
	for (int i = 0; i < Src.rows; i++)
	{
		for (int j = 0; j < Src.cols; j++)
		{
			if (PointLabel.at<uchar>(i,j) == 0)//標籤影象畫素點為0,表示還未檢查的不合格點 
			{ //開始檢查 
				vector<Point2i>GrowBuffer;//記錄檢查畫素點的個數 
				GrowBuffer.push_back(Point2i(j,i));
				PointLabel.at<uchar>(i,j) = 1;//標記為正在檢查 
				int CheckResult = 0;
				for (int z = 0; z < GrowBuffer.size(); z++)
				{
					for (int q = 0; q < NeihborCount; q++)
					{
						CurrX = GrowBuffer.at(z).x + NeihborPos.at(q).x;
						CurrY = GrowBuffer.at(z).y + NeihborPos.at(q).y;
						if (CurrX >= 0 && CurrX<Src.cols&&CurrY >= 0 && CurrY<Src.rows) //防止越界 
						{
							if (PointLabel.at<uchar>(CurrY,CurrX) == 0)
							{
								GrowBuffer.push_back(Point2i(CurrX,CurrY)); //鄰域點加入buffer 
								PointLabel.at<uchar>(CurrY,CurrX) = 1;   //更新鄰域點的檢查標籤,避免重複檢查 
							}
						}
					}
				}
				if (GrowBuffer.size()>AreaLimit) //判斷結果(是否超出限定的大小),1為未超出,2為超出 
					CheckResult = 2;
				else
				{
					CheckResult = 1;
					RemoveCount++;//記錄有多少區域被去除 
				}
				for (int z = 0; z < GrowBuffer.size(); z++)
				{
					CurrX = GrowBuffer.at(z).x;
					CurrY = GrowBuffer.at(z).y;
					PointLabel.at<uchar>(CurrY,CurrX) += CheckResult;//標記不合格的畫素點,畫素值為2 
				}
				//********結束該點處的檢查********** 
			}
		}
	}
	CheckMode = 255 * (1 - CheckMode);
	//開始反轉面積過小的區域 
	for (int i = 0; i < Src.rows; ++i)
	{
		for (int j = 0; j < Src.cols; ++j)
		{
			if (PointLabel.at<uchar>(i,j) == 2)
			{
				Dst.at<uchar>(i,j) = CheckMode;
			}
			else if (PointLabel.at<uchar>(i,j) == 3)
			{
				Dst.at<uchar>(i,j) = Src.at<uchar>(i,j);
			}
		}
	}
	//cout << RemoveCount << " objects removed." << endl;
}
//=======函式實現=====================================================================
//=======呼叫函式=====================================================================
	Mat img;
	img = imread("D:\\1_1.jpg",0);//讀取圖片
	threshold(img,img,128,CV_THRESH_BINARY_INV);
	imshow("去除前",img);
	Mat img1;
	RemoveSmallRegion(img,1);
	imshow("去除後",img);
	waitKey(0);
//=======呼叫函式=====================================================================

以上這篇使用OpenCV去除面積較小的連通域就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支援我們。