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How To Smooth The Image Edge
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behnam emami
on 27 May 2015
Commented: Harshan Desu
on 1 May 2020
<<
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/150651/image.png)
>>i use : image=imread('hand.png'); e=edge(image,'canny'); imshow(e);
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Accepted Answer
Salaheddin Hosseinzadeh
on 27 May 2015
Edited: Salaheddin Hosseinzadeh
on 27 May 2015
Salam Behnam!
I guess by smoothing you mean getting rid of the jagged edges.
What do you think of performing a dilation with a huge radial element and then perform thining?
I just did this here is the result
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/177131/image.png)
I hope this is good enough. I did it with a disk of 10 pixels radious you maybe reduce/increase the disk size and get a better smoothing.
Good Luck!
3 Comments
Salaheddin Hosseinzadeh
on 27 May 2015
Edited: Salaheddin Hosseinzadeh
on 27 May 2015
Dear Behnam,
You can search MATLAB help for the keywords in my answer. Please also have a look at Image Analyst response, that is far more scientific.
dilatedImage = imdilate(image,strel('disk',10));
thinedImage = bwmorph(dilatedImage,'thin',inf);
Good luck!
More Answers (1)
Image Analyst
on 27 May 2015
Edited: Image Analyst
on 27 Jan 2016
One way is to blur the image with imfilter() or conv2() before you do the edge detection. Another way is to smooth the outline coordinates with a Savitzky-Golay filter, sgolayfilt() in the Signal Processing Toolbox.
See demo and image in the comment below - tell it to show the older comments because it's collapsed now.
19 Comments
Image Analyst
on 9 Apr 2020
I don't know the resolution. Maybe those jaggies are just one pixel big? If so, you'd have to increase the number of pixels then blur and threshold.
Harshan Desu
on 1 May 2020
I have tired working on it for the past two weeks sir, I couldnt still get what I want. Let me explain my project clearly.. Please suggest me how I can work on it.
Project: Finding the edges of a door and used those edges as a trajectory for a sensor that checks edges for Gap/Flush.
Problem: I used Savitzky Golay, Edge Linking and Line Segment Fitting from your blog:
(https://www.peterkovesi.com/matlabfns/#step2line). After all this I am not able to get good edges, its either not smooth or has a lot of unnecessary edges.
Method I used: Image Analyst's Savitzky filter smoothening at three diffrent thresholds, obtain three images and blend them. The output is again processed to Edge linking and line segmenting program which I got from ur blog.
Questions:
- How to remove unnecessary edges out of the image.
- How to smoothening images so that i can use it for trajectory
You can also see my question: https://www.mathworks.com/matlabcentral/answers/519030-how-to-extract-curves-from-edges-of-a-complex-image?s_tid=prof_contriblnk
I have attached the images of my last output.
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