OpenCV图像处理（4）——去除小面积

去除小面积(注：输出图像需要初始化，否则会报错)
/*
参数说明：1.输入图像，
2.输出图像（去除掉指定小面积后的图像），
3.需要去除的面积，
4.去除方式（==1去除小连通区域的白色点，==0去除孔洞，黑色点像素）
5.邻域方式：NeihborMode == 1八邻域，NeihborMode == 0四邻域
*/
void RemoveSmallRegion(Mat &Src, Mat &Dst, int AreaLimit, int CheckMode, int NeihborMode)
{
 int RemoveCount = 0;
 //新建一幅标签图像初始化为0像素点，为了记录每个像素点检验状态的标签，0代表未检查，1代表正在检查,2代表检查不合格（需要反转颜色），3代表检查合格或不需检查 
 //初始化的图像全部为0，未检查
 Mat PointLabel = Mat::zeros(Src.size(), CV_8UC1);
 if (CheckMode == 1)//去除小连通区域的白色点
 {
  //cout << "去除小连通域.";
  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;//将背景黑色点标记为合格，像素为3
    }
   }
  }
 }
 else//去除孔洞，黑色点像素
 {
  //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;//如果原图是白色区域，标记为合格，像素为3
    }
   }
  }
 }
 vector<Point2i>NeihborPos;//将邻域压进容器
 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邻域." << 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 cout << "Neighbor mode: 4邻域." << endl;
 int NeihborCount = 4 + 4 * NeihborMode;
 int CurrX = 0, CurrY = 0;
 //开始检测
 for (int i = 0; i < Src.rows; i++)
 {
  for (int j = 0; j < Src.cols; j++)
  {
   if (PointLabel.at<uchar>(i, j) == 0)//标签图像像素点为0，表示还未检查的不合格点
   {   //开始检查
    vector<Point2i>GrowBuffer;//记录检查像素点的个数
    GrowBuffer.push_back(Point2i(j, i));
    PointLabel.at<uchar>(i, j) = 1;//标记为正在检查
    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));  //邻域点加入buffer  
        PointLabel.at<uchar>(CurrY, CurrX) = 1;           //更新邻域点的检查标签，避免重复检查  
       }
      }
     }
    }
    if (GrowBuffer.size() > AreaLimit) //判断结果（是否超出限定的大小），1为未超出，2为超出  
     CheckResult = 2;
    else
    {
     CheckResult = 1;
     RemoveCount++;//记录有多少区域被去除
    }

    for (int z = 0; z < GrowBuffer.size(); z++)
    {
     CurrX = GrowBuffer.at(z).x;
     CurrY = GrowBuffer.at(z).y;
     PointLabel.at<uchar>(CurrY, CurrX) += CheckResult;//标记不合格的像素点，像素值为2
    }
    //********结束该点处的检查**********  
   }
  }
 }
 CheckMode = 255 * (1 - CheckMode);
 //开始反转面积过小的区域  
 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;
}