flip and rotate a color image in MATLAB

Question

How do I flip a color image (RGB) in MATLAB? The fliplr does not seem to work without losing the color contents, as it only deals with 2D.

As well, the imrotate may not rotate color images.

I have no problems rotating color images with `imrotate` (R2013a). — Cape Code, Dec 30 '13 at 13:43
`fliplr(img)` is equivalent to `flip(img, 2)`. And it deal not only with 2D arrays. For multidimensional arrays, `fliplr` operates on the planes formed by the first and second dimensions. — Temak, Sep 28 '15 at 17:18

gnovice · Accepted Answer · 2016-10-06T15:05:11.380

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The function flipdim will work for N-D matrices, whereas the functions flipud and fliplr only work for 2-D matrices:

img = imread('peppers.png');     %# Load a sample image
imgMirror = flipdim(img,2);      %# Flips the columns, making a mirror image
imgUpsideDown = flipdim(img,1);  %# Flips the rows, making an upside-down image

NOTE: In more recent versions of MATLAB (R2013b and newer), the function flip is now recommended instead of flipdim.

edited Oct 06 '16 at 15:05

answered Oct 25 '10 at 16:02

gnovice

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Please, replace `flipdim()` by `flip()`, since the former is not recommended because of various reasons. – Léo Léopold Hertz 준영 Oct 06 '16 at 14:40

Amro · Answer 2 · 2016-10-06T13:37:02.220

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An example:

I = imread('onion.png');
I2 = I(:,end:-1:1,:);           %# horizontal flip
I3 = I(end:-1:1,:,:);           %# vertical flip
I4 = I(end:-1:1,end:-1:1,:);    %# horizontal+vertical flip

subplot(2,2,1), imshow(I)
subplot(2,2,2), imshow(I2)
subplot(2,2,3), imshow(I3)
subplot(2,2,4), imshow(I4)

alt text

edited Oct 06 '16 at 13:37

answered Oct 24 '10 at 20:10

Amro

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I also like it better this way. – Jonas Oct 06 '16 at 13:38
yep :) Besides others had already shown how to use `flipdim` and its new replacement `flip`. – Amro Oct 06 '16 at 13:41
@Amro New thread here about flipping `imagesc` + `axes` in an integrated approach http://stackoverflow.com/q/39923300/54964 - - I am not confident that your approach can maintain `axes`. – Léo Léopold Hertz 준영 Oct 07 '16 at 17:58

score 2 · Answer 3 · answered Aug 07 '13 at 18:20

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imrotate rotates color images B = IMROTATE(A,ANGLE) rotates image A by ANGLE degrees in a counterclockwise direction around its center point.

answered Aug 07 '13 at 18:20

Chethan

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score 0 · Answer 4 · answered Feb 05 '16 at 18:13

I know it is late, but since flipdim is now depreciated, other answers are not valid anymore. You could use flip, or do it in other, smart way:

I = imread('onion.png');

% flip left-right, or up-down:

Iflipud = flip(I, 1)
Ifliplr = flip(I, 2)

% or:
Iflipud = I(size(I,1):-1:1,:,:);
Ifliplr = I(:,size(I,1):-1:1,:);

% flip both left-right, and up-down, stupid way:
Iflipboth = I(size(I,1):-1:1,size(I,1):-1:1,:);

% flip both left-right, and up-down, smart way:):
Iflipboth = imrotate(I, 180)

As already pointed, imrotate deals with color images as well as with greyscale.

flip and rotate a color image in MATLAB

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