supremum of openings by set of linear structuring elements

I want to extract elongated structures with using angle of rotation like r=[15....90;-15...-90] so that supremum of opening consists of set of lines.

so how i should proceed

[Image Analyst]

First you should attach your images so we can see if imopen() is the best approach to get your elongated structures. I mean, why not just threshold and call regionprops to get the orientations (angles)? I don't know because you did not attach your image.

[rky]

Basically i want to extract blood vessels from my retinal images

Answer 1

[Image Analyst]

See section 20.5 for algorithms: http://www.visionbib.com/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models

[rky]

Thanks for above link

Linear structuring element for opening operation can be applied as below example

 while(i<360)
         se=strel('line',17,i);
         i=i+15;
         img=imopen(img,se);
    end

but how to find supremum of opening

Thanks

[Image Analyst]

Define supremum. Do you just mean the max? Why not just do

openedImage = imopen(originalImage,se);
if i == 0
  resultImage = openedImage;
else
  resultImage = max(resultImage, openedImage);
end

[rky]

if i want angle of rotation i = [15....90;-15...-90] and also [105...180;195...270] how i should do .