samples/cpp/tutorial_code/ImgProc/Morphology_1.cpp

Erosion and Dilation sample code

Sample Screenshot-Erosion

Sample Screenshot-Dilation

Check the corresponding tutorial for more details

#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>

using namespace cv;
using namespace std;

Mat src, erosion_dst, dilation_dst;

int erosion_elem = 0;
int erosion_size = 0;
int dilation_elem = 0;
int dilation_size = 0;
int const max_elem = 2;
int const max_kernel_size = 21;

void Erosion( int, void* );
void Dilation( int, void* );

int main( int argc, char** argv )
{
  CommandLineParser parser( argc, argv, "{@input | LinuxLogo.jpg | input image}" );
  src = imread( samples::findFile( parser.get<String>( "@input" ) ), IMREAD_COLOR );
  if( src.empty() )
  {
    cout << "Could not open or find the image!\n" << endl;
    cout << "Usage: " << argv[0] << " <Input image>" << endl;
    return -1;
  }

  namedWindow( "Erosion Demo", WINDOW_AUTOSIZE );
  namedWindow( "Dilation Demo", WINDOW_AUTOSIZE );
  moveWindow( "Dilation Demo", src.cols, 0 );

  createTrackbar( "Element:\n 0: Rect \n 1: Cross \n 2: Ellipse", "Erosion Demo",
          &erosion_elem, max_elem,
          Erosion );

  createTrackbar( "Kernel size:\n 2n +1", "Erosion Demo",
          &erosion_size, max_kernel_size,
          Erosion );

  createTrackbar( "Element:\n 0: Rect \n 1: Cross \n 2: Ellipse", "Dilation Demo",
          &dilation_elem, max_elem,
          Dilation );

  createTrackbar( "Kernel size:\n 2n +1", "Dilation Demo",
          &dilation_size, max_kernel_size,
          Dilation );

  Erosion( 0, 0 );
  Dilation( 0, 0 );

  waitKey(0);
  return 0;
}


void Erosion( int, void* )
{
  int erosion_type = 0;
  if( erosion_elem == 0 ){ erosion_type = MORPH_RECT; }
  else if( erosion_elem == 1 ){ erosion_type = MORPH_CROSS; }
  else if( erosion_elem == 2) { erosion_type = MORPH_ELLIPSE; }

  Mat element = getStructuringElement( erosion_type,
                       Size( 2*erosion_size + 1, 2*erosion_size+1 ),
                       Point( erosion_size, erosion_size ) );

  erode( src, erosion_dst, element );
  imshow( "Erosion Demo", erosion_dst );
}


void Dilation( int, void* )
{
  int dilation_type = 0;
  if( dilation_elem == 0 ){ dilation_type = MORPH_RECT; }
  else if( dilation_elem == 1 ){ dilation_type = MORPH_CROSS; }
  else if( dilation_elem == 2) { dilation_type = MORPH_ELLIPSE; }

  Mat element = getStructuringElement( dilation_type,
                       Size( 2*dilation_size + 1, 2*dilation_size+1 ),
                       Point( dilation_size, dilation_size ) );

  dilate( src, dilation_dst, element );
  imshow( "Dilation Demo", dilation_dst );
}