Each data point plots as individual points not as one set of many points

Question

Abraham Cisneros 2021-11-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1595179-each-data-point-plots-as-individual-points-not-as-one-set-of-many-points

评论： Abraham Cisneros 2021-11-28

Screen Shot 2021-11-24 at 2.06.12 PM.png

I'm plotting data from a video file, the plot looks as it should, however, I would like to run findpeaks function to locate local maxima throughout the plot. But since each data point is its own individual element, findpeaks or curve fitting does not work. How can I combine all the data points into one set? I attached a screenshot of how the data is currently plotting .

obj = VideoReader('VidName.avi') %same name as file you create in step 1
video = read(obj);
for i=1:150 %number of frames of the video i am analyzing 
     avrgG(i)=mean2(video(400:420,580:600,2,i)); %color channel im plotting
     plot(i,avrgG(i),'ko') %plot the channel you want
     title('Green Channel Intensity Plot');
     xlabel('Number of Frames');
     ylabel('Intensity of Green Channel (counts)');
     hold on
     pause(.2)
 end

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Answer 1

Kevin Holly 2021-11-24

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1595179-each-data-point-plots-as-individual-points-not-as-one-set-of-many-points#answer_839679

编辑：Kevin Holly 2021-11-24

在 MATLAB Online 中打开

obj = VideoReader('VidName.avi') %same name as file you create in step 1
video = read(obj);
for i=1:150 %number of frames of the video i am analyzing 
    avrgG(i)=mean2(video(400:420,580:600,2,i)); %color channel im plotting
end
plot(1:150,avrgG,'ko') %plot the channel you want
title('Green Channel Intensity Plot');
xlabel('Number of Frames');
ylabel('Intensity of Green Channel (counts)');

If you still want to see a data point added during for loop:

obj = VideoReader('VidName.avi') %same name as file you create in step 1
video = read(obj);
     avrgG(1)=mean2(video(400:420,580:600,2,1)); %color channel im plotting
     p = plot(1,avrgG(1),'ko') %plot the channel you want
     title('Green Channel Intensity Plot');
     xlabel('Number of Frames');
     ylabel('Intensity of Green Channel (counts)');
for i=2:150 %number of frames of the video i am analyzing 
     avrgG(i)=mean2(video(400:420,580:600,2,i)); %color channel im plotting
     p.XData = [p.XData i];
     p.YData = [p.YData avrgG(i)];
     pause(.2)
 end

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Abraham Cisneros 2021-11-28

Thank you for the quick reply this is what I needed

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Answer 2

Yongjian Feng 2021-11-24

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1595179-each-data-point-plots-as-individual-points-not-as-one-set-of-many-points#answer_839674

在 MATLAB Online 中打开

plot can take arrays as inputs.

So take the plot call out of the for loop.

obj = VideoReader('VidName.avi') %same name as file you create in step 1
video = read(obj);
for i=1:150 %number of frames of the video i am analyzing 
     avrgG(i)=mean2(video(400:420,580:600,2,i)); %color channel im plotting
     pause(.2) % MIGHT NOT NEED THIS.
end
x = 1:150;
plot(x,avrgG,'ko') %plot the channel you want
title('Green Channel Intensity Plot');
xlabel('Number of Frames');
ylabel('Intensity of Green Channel (counts)');