getLabelContourMask

getLabelContourMask

void CSID::getLabelContourMask(cv::Mat &mask, bool _thick_line)
{
    // default width
    int line_width = 2;

    if ( !_thick_line ) line_width = 1;
    int width = m_matData.cols;
    int height = m_matData.rows;
    mask.create(height, width, CV_8UC1 );


    mask.setTo(0);

    const int dx8[8] = { -1, -1,  0,  1, 1, 1, 0, -1 };
    const int dy8[8] = {  0, -1, -1, -1, 0, 1, 1,  1 };

    int sz = width*height;

    std::vector<bool> istaken(sz, false);

    int mainindex = 0;
    for( int j = 0; j < height; j++ )
    {
      for( int k = 0; k < width; k++ )
      {
        int np = 0;
        for( int i = 0; i < 8; i++ )
        {
          int x = k + dx8[i];
          int y = j + dy8[i];

          if( (x >= 0 && x < width) && (y >= 0 && y < height) )
          {
            int index = y*width + x;

            if( false == istaken[index] )
            {
              if( m_labelData.at<int>(j,k) != m_labelData.at<int>(y,x) ) np++;
            }
          }
        }
        if( np > line_width )
        {
           mask.at<char>(j,k) = -1;
           istaken[mainindex] = true;
        }
        mainindex++;
      }
    }
}