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Figure to play and analyze videos with custom plots on top

version 1.1 (3.79 KB) by

A figure ready to scroll through and play videos. You can also draw any custom graphics on it.

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Editor's Note: This file was selected as MATLAB Central Pick of the Week

VIDEOFIG(NUM_FRAMES, @REDRAW_FUNC) creates a figure with a horizontal scrollbar and shortcuts to scroll automatically. The scroll range is 1 to NUM_FRAMES. The function REDRAW_FUNC(F) is called to redraw at scroll position F (for example, REDRAW_FUNC can show the frame F of a video).

This can be used not only to play and analyze standard videos, but it also lets you place any custom Matlab plots and graphics on top.

Jiro posted a great example on the Pick of the Week blog, along with a nice GIF animation so you can see it in motion:
http://blogs.mathworks.com/pick/2010/12/10/video-player-for-your-frame-based-processing/

EXAMPLE 1

Place this in a file called "redraw.m":
function redraw(frame)
imshow(['AT3_1m4_' num2str(frame, '%02.0f') '.tif'])
end

Then from a script or the command line, call:
videofig(10, @redraw);
redraw(1)

The images "AT3_1m4_01.tif" ... "AT3_1m4_10.tif" are part of the Image
Processing Toolbox and there's no need to download them elsewhere.

EXAMPLE 2

Change the redraw function to visualize the contour of a single cell:
function redraw(frame)
im = imread(['AT3_1m4_' num2str(frame, '%02.0f') '.tif']);
slice = im(210:310, 210:340);
[ys, xs] = find(slice < 50 | slice > 100);
pos = 210 + median([xs, ys]);
siz = 3.5 * std([xs, ys]);
imshow(im), hold on
rectangle('Position',[pos - siz/2, siz], 'EdgeColor','g', 'Curvature',[1, 1])
hold off
end


The keyboard shortcuts are:
Enter (Return) -- play/pause video (25 frames-per-second default).
Backspace -- play/pause video 5 times slower.
Right/left arrow keys -- advance/go back one frame.
Page down/page up -- advance/go back 30 frames.
Home/end -- go to first/last frame of video.

See HELP VIDEOFIG for more options.

Comments and Ratings (2)

Renaud

Renaud (view profile)

Very Helpful function!!!
One question: Is there a way to save the processed frames into an .avi file?

Thanks!!

Iván

Iván (view profile)

This is excellent!!
It's more than what I was looking for!
Thanks! =)

Updates

1.1

Added a link to Jiro's example, and rearranged the file's description a bit.

MATLAB Release
MATLAB 7.7 (R2008b)
Acknowledgements

Inspired: Reader class for Photron .mraw-Files

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