Plot a line over every frame in a for loop
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Experts,
I extracted the frames from a video and detected the edges of the moving object. Then drew a line that passes from the very top pixel of the boundary. I want the line to appear on every frame,However, the line only appears for the last frame.In addition, I need to label the y value of the line as well. Can you please help me. Here is the code and the image. I added the yellow arrow on the image with powerpoint to be clear. The left frame is missing the line and the image in the right is the last frame which has a line.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/171634/image.jpeg)
if true
for i=1:10
FileName=strcat(num2str(i),'.jpg');
Im=imread(FileName);
Im=imcrop(Im,[600 100 500 500]);
Im = im2double(Im);
Im=im2bw(Im,0.8);
Im = edge(Im,'Sobel');
imshow(Im)
[y, x] = find(Im);
H(w)=min(y);
w=w+1;
line([0 length(Im)], [min(y) min(y)])
end
end
0 Comments
Accepted Answer
Kai Domhardt
on 28 Mar 2018
Edited: Kai Domhardt
on 28 Mar 2018
You need to a pause inbetween frames, before the next imshow(Im) executes.
Adding
pause(0.1)
as the final line inside your for-loop will solve your problem and display every frame for 0.1 seconds.
3 Comments
Kai Domhardt
on 28 Mar 2018
You could do something like
font_size = 14;
text(0, font_size, ['Height: ' num2str(min(y))], 'Color', 'white','FontSize',font_size)
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