Detect Edges having length greater than 50km

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Hi all,
I have detected edges using Canny Edge detector. But I want to detect Edges having length greater than 50km. I have attached code. Can anyone help me to edit code to detect edges of given length?
X = cell2mat(struct2cell(load('F:\study\practise\New folder\2010\script\preprocessed2010.mat', 'Alpha')));
for k=1:length(X)
b=X(k).img;
b(b==0)=NaN;
b (b > -5) = NaN;
b (b < -32) = NaN;
figure, temp1 = imagesc(b);title('Original Image') ;colormap('gray'); colorbar;
baseFileName = sprintf('%d.jpg',k);
% % % Specify some particular, specific folder:
fullFileName = fullfile('E:\practise\images', baseFileName);
figure(gcf); % Activate the figure again.
export_fig(fullFileName);
% Get edges
A = edge(b, 'canny');
figure, temp1 = imagesc(A);title('Edge Detected Image') ;colormap('gray'); colorbar;
baseFileName = sprintf('%dCanny.jpg',k);
fullFileName = fullfile('E:\practise\images', baseFileName);
figure(gcf); % Activate the figure again.
export_fig(fullFileName);
%
end

Accepted Answer

Image Analyst
Image Analyst on 19 Oct 2020
You forgot to attach preprocessed2010.mat.
After you get the binary image, A, you can call bwareaopen() to extract only those blobs with area more than however many pixels 50 km is;
fiftyKm = round(50 * pixelsPerKm);
A50 = bwareaopen(A, fiftyKm);
  2 Comments
Nadia jabeen
Nadia jabeen on 20 Oct 2020
Pixel area is 30*30m. I want to extract edges having length more than 50km.
Nadia jabeen
Nadia jabeen on 20 Oct 2020
I don't want to extract pixels. All edges have been extracted from bwareaopen() function.

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