How can I add timer to a stack of image and play it as a video with timer going on in the corner of it?

I have a stack of radiography images which are taken in time and would like to save it as a video with a TIMER in the video. The time is important to see when video plays.

Answer 1

[DGM]

See this thread

https://www.mathworks.com/matlabcentral/answers/101413-how-can-i-add-text-to-an-image-and-make-the-text-become-part-of-the-image-within-matlab

There are various ways to generate the text as a raster image, and there are various ways to combine the text image with the main image. If you have CVT, you can use inserttext(). If you don't, your options depend on how large your images are.

If your images are large enough, you might try text rendering via figure capture. This has limitations and is generally cumbersome and can alter image content if you're not careful, but it's possible. One convenient approach to figure capture is this FEX tool:

https://www.mathworks.com/matlabcentral/fileexchange/40959-add-text-to-image

If your images are relatively small, using figure capture is going to be severely limited by the antialiasing and available fonts. Simply put, it can't render readable text at small scales. Either you'd have to upscale your images, or you'd have to be careful about font choices. Alternatively, you can use any one of the text-to-image conversion tools that's listed in the first link.

This example uses textim() from MIMT, though no other MIMT tools are used.

% i assume you already have some image stack in the workspace
% i assume it is arranged with frames on dim 4
% i assume it is an RGB image of class uint8
[h,w,nchans,nframes,~] = size(framestack);

% create output object
outvid = VideoWriter('garbage.avi');
outvid.FrameRate = 29.97;

% load dummy image to set axes and create image object for display purposes
hi = imshow(zeros(h,w,nchans));

% process frames
invid.CurrentTime = timerange(1);
open(outvid);
for f = 1:nframes
    % read the frame
    thisframe = framestack(:,:,:,f);
    
    % get text as an image block
    thistime = rand(1); % generate your number somehow (this is a placeholder)
    stampstr = sprintf('time: %.4f',thistime); % format it as a char somehow
    stampimg = textim(stampstr,'ibm-vga-16x9'); % turn it into an image somehow
    
    % insert text block into image somewhere
    [hs,ws,~] = size(stampimg);
    stampimg = repmat(stampimg,[1 1 nchans]); % expand to match number of channels
    stampimg = im2uint8(stampimg); % cast and rescale to match class
    thisframe(1:hs,1:ws,:) = stampimg; % northwest corner
    
    % write and display frame
    writeVideo(outvid,thisframe); % write the frame
    hi.CData = thisframe; % update display
    pause(1/outvid.FrameRate);
end
close(outvid);

If your images are arranged differently, or if they have different class or depth, then you'll have to make those changes. You'll have to figure out how to generate and format the timestamps you want. I'm just printing random numbers as a placeholder.