How can I measure the length of these line segments in this image mask?

I have a binary image (BW_roi.mat attached) like this. And I wanted to measure the length of every line segment.

I tried the solution given in this link hough-transform. But it does not work out for me. It just measured the length of some lines as shown below.

I tried the other code

boundaries = bwboundaries(BW);
patchno=1
b = boundaries{patchno}; % Extract N by 2 matrix of (x,y) locations.
x = b(:, 1);
y = b(:, 2);

It though give me points (x,y) that make up these polygons. But how can I get the length of the sides of these patches?

[darova]

Try bwlabel

Answer 1

[yanqi liu]

clc; clear all; close all;
load BW_ROI.mat
b = BW_roi_nodot;
b = ~b;
% measure the length of every line segment
% b([1 end],:) = 1;
% b(:,[1 end]) = 1;
b = logical(b);
b2 = imfill(b, 'holes');
b3 = b2 - b;
b3 = logical(b3);
b4 = imclose(b3, strel('disk', 5));
b5 = imopen(b2, strel('square',7));
b6 = b2 - b5;
b6 = logical(b6);
[L, num] = bwlabel(b3);
stats = regionprops(L,'ConvexHull');
figure; imshow(BW_roi_nodot); hold on;
for i = 1 : num
    p = stats(i).ConvexHull;
    plot(p(:,1), p(:,2),'LineWidth',2);
end

[Masood Salik]

The code directly give us the boundries of the part. We don't need further refinement.

boundaries = bwboundaries(BW_roi_nodot);

I need a code or algoritam that find the vertices of the polygons, generated by bwboundries. Then afterward I can find the lengths easily.