How can I insert graphics into existing images?

I have images that I would like to add data to, for example, text or smaller images.

Answer 1

[MathWorks Support Team]

This change has been incorporated into the documentation in Release 14 Service Pack 3 (R14SP3). For previous releases, read below for any additional information:

You can use basic array indexing to insert data into existing images. The following is an example:

% Create and style the text in an axis:

t = text(.05,.1,'Mandrill Face',  'FontSize',12, 'FontWeight','demi');

% Capture the text from the screen:

F = getframe(gca,[10 10 200 200]);

% Close the figure:

close

% Select any plane of the resulting RGB image:

c = F.cdata(:,:,1);

% Note: If you have the Image Processing Toolbox installed,

% you can convert the RGB data from the frame to black or white:

% c = rgb2ind(F.cdata,2);

% Determine where the text was (black is 0):

[i,j] = find(c == 0);

% Read in or load the image that is to contain the text:

load mandrill

% Use the size of that image, plus the row/column locations

% of the text, to determine locations in the new image:

ind = sub2ind(size(X),i,j);

% Index into new image, replacing pixels with white:

X(ind) = uint8(255);

% Display and color the new image:

imagesc(X)

colormap(bone)