insert text into image without computer vision system toolbox - Matlab

Question

In the Matlab central (http://www.mathworks.com/matlabcentral/answers/26033-how-to-insert-text-into-image) I found this code:

Text = sprintf('Create text inserter object \nwith same property values');
H = vision.TextInserter(Text);
H.Color = [1.0 1.0 0];
H.FontSize = 20;
H.Location = [25 25];
I = im2double((imread('football.jpg')));
InsertedImage = step(H, I);
imshow(InsertedImage);

How can I do the same without using the computer vision system toolbox?

Thanks

simply use a text annotation and it will work just fine. http://www.mathworks.com/help/matlab/ref/text.html — Benoit_11, Oct 15 '14 at 15:00

score 4 · Accepted Answer · edited May 23 '17 at 11:47

4

To follow up on my comment:

A = imread('football.jpg');

YourText = sprintf('Create text inserter object \nwith same property values');

figure;

imshow(A);

hText = text(25,25,YourText,'Color',[1 1 0],'FontSize',20);

Giving the following:

enter image description here

Look at the doc page to see all the options available to modify/customize your text. Notice that you don't have to use sprintf to generate the string, however the newline character (\n) must be used inside sprintf in order to work.

EDIT In response to your comment below, if you need to save the image with text embedded in it you can use getframe to get the content of the figure and then imwrite to save it:

hFrame = getframe(gca) %// Get content of figure

imwrite(hFrame.cdata,'MyImage.tif','tif') %// Save the actual data, contained in the cdata property of hFrame

EDIT #2 As alternatives to using getframe, look here as there are 2 nice ideas proposed, i.e. using saveas or avi files.

edited May 23 '17 at 11:47

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answered Oct 15 '14 at 15:05

Benoit_11

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Thanks and what can I do it embedded it in the image? – hs100 Oct 15 '14 at 15:08
do you mean save the image with the text in it? – Benoit_11 Oct 15 '14 at 15:09
Yes. A new image is fine. – hs100 Oct 15 '14 at 15:11
Thank.I presume it will not work inside a GUI since you advised using getframe. Am I right? is there another solution? – hs100 Oct 15 '14 at 15:21
Yep it should work just fine inside a GUI, although you do need an axes in which to display the image. I'll think about it for a possible workaround – Benoit_11 Oct 15 '14 at 15:25
I added a link to another answer here on SO for the alternatives to getframe. – Benoit_11 Oct 15 '14 at 16:49

Hazem · Answer 2 · 2015-06-23T09:41:30.087

The answer above (Benoit_11) requires that you display the image first, write the text, then save the image. This becomes very slow if you are processing the frames of a video (not a single image, or a few of them). To get a much faster processing time, you have to write directly to the image matrix. One alternative I can think of (but that is not very elegant) is to create (or download) small templates for the alphabet characters (e.g. 20x20), then overwrite the image matrix in the required region with those templates. For example, for an RGB "true color" image, we'll have something like this:

im(y:y+19,x:x+19,:)=template;

insert text into image without computer vision system toolbox - Matlab

2 Answers2