Video Display with Histogram

Question

Veilchen1900 2017-6-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/343546-video-display-with-histogram

评论： Gholamreza Jahangiri 2020-2-4

Hi,

I want to run at the left side of my figure a video and to show at the right side the corresponding live histogram. First of all, is this possible in Matlab?

I have a code to run the video and one to display the histograms. But it didn't work together. Thanks in advance for every hint!

First code:

   % Display video
v = VideoReader('myVideo.avi');
ii = 1;
while hasFrame(v)
   mov(ii) = im2frame(readFrame(v));
   ii = ii+1;
end
movie(gcf,mov)

Second code:

 % Display histograms
v = VideoReader('myVideo.avi');
while hasFrame(v)
    thisFrame= readFrame(v);  % Get one RGB frame of the color video.
    redChannel = thisFrame(:,:,1); % Extract red channel only.
    [pixelCounts, grayLevels] = imhist(redChannel); % Get histogram of red channel.
    figure(1), subplot (1,2,2),stem(grayLevels, pixelCounts);
end

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Answer 1

Gaurav Ahuja 2017-6-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/343546-video-display-with-histogram#answer_270108

在 MATLAB Online 中打开

SampleVideo_640x360_1mb.zip

I think this should help.

if true
  v = VideoReader('SampleVideo_640x360_1mb.mp4');
  ii = 1;
  while hasFrame(v)
  f= readFrame(v);
  mov(ii) = im2frame(f);
  ii = ii+1;
  subplot (1,2,1)
  imshow (f)
  thisFrame= f;  % Get one RGB frame of the color video.
  redChannel = thisFrame(:,:,1); % Extract red channel only.
  [pixelCounts, grayLevels] = imhist(redChannel); % Get histogram of red channel.
  figure(1), subplot (1,2,2),stem(grayLevels, pixelCounts);
  drawnow;
end
end

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Gholamreza Jahangiri 2020-2-4

Hi,

I need this code with some modifiation. I want to make each frame to gray scale, and then get the minimum value for each pixel in the video and build a hisogram to apply that histogram to the video. So, I have a video with no changing in brighness, just need the movements of pixels.

Thanks

Reza

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