Fixed number of frames video buffer

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Eirik Furuholt
Eirik Furuholt on 21 Apr 2021
I get a new picture from my camera every 100ms. I want to store some frames to understand what happens before and after an event.
How can I implement a buffer that continuously saves the last 30 pictures?
The last lines of code shows what I want to do.
Any help with the saving of frames after the trigger event is also appreciated, but I think I can do it.
while true
%get video
I = videoinput('winvideo', 2, 'YUY2_1280x720');
I.ReturnedColorspace = 'rgb';
I = getsnapshot(I);
vid.ROIPosition = [585 400 648 313]; % crop the image to smaller ROI
% preprosess the image
I = imresize(I,frameSize);
I= imsubtract(I,background);
I = imadjust(I,[low high]);
%----------------------------------- save last 30 frames of I
% if something happens
% save 30 more more frames
% merge the two videos
Eirik Furuholt
Eirik Furuholt on 21 Apr 2021
Hello Walter,
Thank you for your reply.
In the link you provided I cannot see a solution to logging just the last few seconds. This camera will run for weeks and I will quickly run out of disk space if I log continuously. Could you please explain further how I can log the last few seconds without losing frames?
Best regards
Eirik F.

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Answers (1)

Shiva Kalyan Diwakaruni
Shiva Kalyan Diwakaruni on 5 May 2021
You can try Creating a video reader object and read one or more video frames using the frame indices.
below is the link to documentation
Hope it helps.

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