CODEWITHSUNDEEP
c++opencv
j.doe
j.doe

Reputation: 327

Opencv Dilation and Skeleton(c++)

I have this image : enter image description here

And I applied dilation with this code :

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


void Dilation( int, void* );

int main( int argc, char** argv )
{

  src = imread("a18.png");

  if( !src.data )
  { return -1; }

  namedWindow( "Dilation Demo", CV_WINDOW_AUTOSIZE );
  cvMoveWindow( "Dilation Demo", src.cols, 0 );

  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 );
//int dilation_size =7;
  /// Default start

  Dilation( 0, 0 );

  waitKey(0);
  return 0;
}

void Dilation( int, void* )
{
  int dilation_type;
  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 );
  imwrite("a18d.png",dilation_dst);
}

And after this step I get this consequent: enter image description here

And the final step is skeleton :

   #include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
int main()
{
    cv::Mat img = cv::imread("a18d.png", 0);
cv::threshold(img, img, 127, 255, cv::THRESH_BINARY); 
cv::Mat skel(img.size(), CV_8UC1, cv::Scalar(0));
cv::Mat temp;
cv::Mat eroded;

cv::Mat element = cv::getStructuringElement(cv::MORPH_CROSS, cv::Size(3,3));

bool done;      
do
{
  cv::erode(img, eroded, element);
  cv::dilate(eroded, temp, element); // temp = open(img)
  cv::subtract(img, temp, temp);
  cv::bitwise_or(skel, temp, skel);
  eroded.copyTo(img);

  done = (cv::countNonZero(img) == 0);
} while (!done);
cv::imshow("Skeleton", skel);
cv::imwrite("18s.png",skel);
cv::waitKey(0);

    return 0;
}

code here

And I hve this image : enter image description here

But I want image like this : enter image description here

What can I do for this? What is the problem these steps was done for Image 4 and result is good

Upvotes: 3

Views: 4932

Answers (1)

Malcolm McLean
Malcolm McLean

Reputation: 6404

Open CV doesn't seem to have a shrink as opposed to an erode operation. At least I can't find it. Try mine

https://github.com/MalcolmMcLean/binaryimagelibrary/blob/master/medialaxistransform.c

Try just using the function "thin" instead of eroding your image.

Upvotes: 1

Related Questions