how do i create mirror images of images in .mat format

I'm basically trying to make a data set for AAM training, I have landmarked several images( video sequence of a frontal pose to moving the head right) and stored them in a .mat format. So now i want a code that will create the mirror image of the annotated images so that i dun have to repeat the process for frontal pose to head moving left on each image.

Answer 1

[Walter Roberson]

fliplr() ?

[sara bokhari]

Tried it din work on the image, also i need two copies of the image the original one and the flipped one. i wrote >> fliplr(005.mat)

[Walter Roberson]

.mat files cannot be flipped. You need to flip the array. For example,

matfilename = '005.mat';
filedata = load(matfilename);
fn = fieldnames(filedata);
for K = 1 : length(fn)
  thisfield = fn{k};
  if strncmp(thisfield, 'flip_', 5)  %do not re-flip
    continue;
  end
  flip_name = ['flip_' thisfield];
  filedata.(flip_name) = fliplr(filedata.(thisfield));
end
save(matfilename, 'filedata', '-struct');

[Image Analyst]

I see you accepted the answer. You must have R2014a - that's good. The fliplr() and flipud() only started working for color images in R2014a, in case anyone was wondering why it didn't work for them on their older version. See Steve's blog: http://blogs.mathworks.com/steve/2014/03/12/r2014a-shipped-and-the-developer-says-wait-what/

[Walter Roberson]

Huh, I thought that was already there! It seems such a small change.

[sara bokhari]

thanku so much for your help .. but im still getting an error

matfilename = '005.mat';
filedata = load(matfilename);
fn = fieldnames(filedata);
for K = 1 : length(fn)
  thisfield = fn{K};
  if strncmp(thisfield, 'flip_', 5)  %do not re-flip
    continue;
  end
  flip_name = ['flip_' thisfield];
  filedata.(flip_name) = fliplr(filedata.(thisfield));
end
save(matfilename, 'filedata', '-struct');

Error using save
The -STRUCT option must be followed by the name of a scalar structure variable.

Also i need to flip over 500 images and i need both the copies the original and flipped.

[Walter Roberson]

save(matfilename, '-struct', 'filedata');

The code does save both the original and the flipped versions; the flipped ones are prefixed with the word 'flip_'. The code can be run multiple times on the same .mat file, as it will not overwrite an existing flip_ version of an image.