使用OpenCV去除面積較小的連通域
阿新 • • 發佈:2020-07-06
這是後期補充的部分,和前期的程式碼不太一樣
效果圖
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
處理前後圖
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=====================================================================
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