CODEWITHSUNDEEP
c++opencvimage-processing
Aadil Jaleel Choudhry
Aadil Jaleel Choudhry

Reputation: 31

OpenCV Erosion / Dilation erroneous output for empty structuring element?

If one erodes an image by zeros(3,3) structuring element, it should be all 1s, but in case of OpenCV, it returns the image. Similarly, dilation of image by zeros(3,3) structuring element return image itself instead of all 0s.

Upvotes: 0

Views: 671

Answers (1)

Kornel
Kornel

Reputation: 5364

The documentation says:

  • element – structuring element used for dilation; if element=Mat() , a 3x3 rectangular structuring element is used

If you take a look at the implementation, you will see that in case of empty kernel the ksize will be 3x3 inside of morphOp() #1683:

Size ksize = !kernel.empty() ? kernel.size() : Size(3,3);

This one also works for me:

cv::Mat input = cv::Mat::eye(10, 10, CV_8UC1);
cv::Mat output;

cv::erode(input, output, cv::Mat());

Upvotes: 2

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