# Detect the shape in MATLAB

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Med Future on 15 Mar 2022
Commented: Image Analyst on 25 Mar 2022
Hello, I hope you are doing well.
I have the image of 1000x1000.I have attached the image below I want to detect the number of lines in the image and pixel value of each line. How can i do it in MATLAB
as you can see in image, there is four lines, is Hough transform work on this or any image processing.
For example line is at 720, then it show pixel value 720
Jan on 15 Mar 2022
Are the lines parallel to the X axis in all cases? Then there are much cheaper methods than a Hough transformation.
Med Future on 16 Mar 2022
Yes line are Parallel. Then how can i detect?

Image Analyst on 15 Mar 2022
% Make the image binary, if it's not already.
binaryImage = grayImage > 128;
% Count the lines.
[LabeledImage, numLines] = bwlabel(binaryImage);
Med Future on 25 Mar 2022
@Image Analyst Thanks for your answer , Like in first image i have half lines and in second image i have full lines , i just want this algo to be that if half line comes it detect half lines and plot y axis half lines as you shared above, if full lines image comes it draw full lines image. the rest of the things are fine.
Image Analyst on 25 Mar 2022
I've given it to you both ways. First I found line segments, with the starting and ending points, then you said you wanted "only unique lines" so if two blobs were on the same line/row, I used unique() to get only unique lines. So if two blobs were on the same row, I'd draw only one line across the whole row. So now you have it both ways. Does that not solve the problem?

yanqi liu on 16 Mar 2022
bw = im2bw(img);
% 霍夫分析
[H,T,R] = hough(bw);
P = houghpeaks(H,5,'threshold',ceil(0.3*max(H(:))));
lines = houghlines(bw,T,R,P,'FillGap',5,'MinLength',7);
max_len = 0;
line_r = [];
figure; imshow(img, []); hold on;
for k = 1:length(lines)
xy = [lines(k).point1; lines(k).point2];
plot(xy(:,1),xy(:,2),'LineWidth',2,'Color','cyan');
p = [];
xy = round(xy);
for j = min(xy(:,1)) : max(xy(:,1))
p = [p img(xy(1,2), j)];
end
text(xy(1,1),xy(1,2)-15, sprintf('pixel value = %.2f', mean(p)), 'color', 'r');
end
Med Future on 19 Mar 2022
@Image Analyst dont understand you answer.
Image Analyst on 19 Mar 2022
Sorry - I put it in the wrong place. it was meant to be a reply to your comment to me

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