MATLAB: How do i count the horizontal lines in an image

image analysisimage processingimage segmentation

I am new to MATLAB. How do i write a code which detects and counts horizontal lines in an image. Example is below. Any method of image analysis would be helpful. Thank you

Best Answer

Thank you for uploading the clean image!
In my view, one simple and straight-forward solution will be regionprops function. The following is one example to extract horizontal lines in the image.
% Read your image and binarize
I = imread('5159-15B front_imgJ-macro.jpg');
I = rgb2gray(I);
BW = imbinarize(I);
% Apply regionprops function
s = regionprops(~BW,{'MajorAxisLength','MinorAxisLength','BoundingBox','Orientation'});
s = struct2table(s);
% Extract the regions which satisfies both the following conditions:
% (1) (Minor axis length)/(Major axis length) <= 10%
% (2) Angle with horizontal line <= +- 5 degree
idx =...
  (s.MinorAxisLength ./ s.MajorAxisLength <= 0.1) &...
  (abs(s.Orientation) <= 5);
s = s(idx,:);
% Show the result
figure
imshow(I)
hold on
for kk = 1:height(s)
  rectangle(...
      'Position', s.BoundingBox(kk,:),...
      'EdgeColor','r')
end
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