I just need to draw that line inside these objects. This line should aproximate these

- I delimited this image in 7 objects

-I don't know how should i determine these points to make that green line from the picture

Answer 1

[Guillaume]

Maybe

skeleton = bwskel(imclose(yourimage, strel('diamond', 2)))

[adrian satmari]

Hmm, thank you @Guillaume!

but, this method is not recognized by Matlab. :( "bwskel"

imshow(BW);hold on;figure
skeleton = bwskel(imclose(BW, strel('diamond', 2)))
imshow(skeleton)

[Image Analyst]

It was introduced in r2018a. Please upgrade.

[Guillaume]

You can use

skeleton = bwmorph(imclose(BW, strel('diamond', 2)), 'skel', Inf);

To get similar (but not identical) results to bwskel. bwskel is an improved version and indeed you'll have to upgrade if you want to use it.

Answer 2

[Image Analyst]

Try

binaryImage = imfill(binaryImage, 'holes');
skelImage = bwmorph(binaryImage, 'skel', inf);

[adrian satmari]

Thank you a lot!

I got something with this code: :D

Now, I am trying to keep only long lines from this.

[Image Analyst]

Unfortunately MATLAB does not have a "longest spine" function. You can use bwmorph() with the 'spur' option but it won't be exactly what you'd want. Contact the Mathworks and ask them for the longest spine option. I've been asking them for years for it.

[adrian satmari]

Thank you again!

I want to mesure this angles, beween the main spine and Y axe,

and for this I tried to aprox. these spines.

I tried with regionprops -> Orienation too, but I think is not helpful.

[Guillaume]

Well, you really need to upgrade!

The bwskel I suggested has an optional input, MinBranchLength which would allow you to trim the skeleton to the main trunk. From then on, the 'Orientation' of regionprops would be a lot more accurate. Unfortunately, bwmorph doesn't have the same option.