Calculate length of white pixels in binary image

I want to calculate the length in pixels of the white pixels at the bottom of the image assuming it is a line without breaks without manually using imdist tool.

Thanks in advance.

[Michael Madelaire]

You should include a data file, such that people willing to help can have a look.

Additionally tou should state some constratints. Is a line only defined if the as being the same row? or can it be diagonally displaced? If so, then how much?

Answer 1

[Eva-Maria Weiss]

Hi!

Assuming that approximating the lineshape structure in the bottom area of your oicture as a line you could try the following

1. Extract the bottom part of your pictur

subFrame = yourPic(rowmiddl:end,:)

2. Now you can find the indices of white pixels by

idx = find(subFrame) %looks for non-zero elements, returns a list

3. Convert linea indexing to subscripts by

[r,c] = ind2sub(size(subFrame),idx)

4. The next step could simply mathematically solved by pythagoras?

qNumbPix = (r(end)-r(1))^2 + (c(end)-c(1))^2
NumbPix = sqrt(qNumbPix

I hope this will help!

Good Luck!

Answer 2

[KALYAN ACHARJYA]

Lets, image_bw is the binary image.(Please not your enclosed image have white boundary, I ignored that)

se=strel('disk',4);
result=imdilate(image_bw,se);
result=bwareafilt(result,1,'Largest');
result=imerode(result,se);
figure,imshow(result);

Next: Find the maximum distance between two white pixels, number of similar question already answered by @ImageAnalyst and @Walter, please do search see here too.

I hope you can do that, please try if not, let me know.