imrotate - clockwise or counterclockwise ?

Question

0 个投票

I observed that imrotate rotates images clockwise instead of counterclockwise, as indicated in the doc.

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Andreas Goser 2011-2-25

I have difficulties to post this as an answer - so doing a "comment".

I modified the example from the doc to see the direction more obvious:

I = fitsread('solarspectra.fts');

I = mat2gray(I);

J = imrotate(I,45,'bilinear','crop');

figure, imshow(I)

figure, imshow(J)

Figure 2 is rotated counterclockwise for me.

David Young 2011-2-25

I also find it rotates the image anticlockwise. (That's the local word for counterclockwise.)

Answer 1

Dan 2011-2-25

1 个投票

Sorry for my remark. I plot images of matrices, and I use Ydir in a 'normal' way. So the rotation is inverted. Thank you for your posts.

David Young 2011-2-25

Yes, but it's not your mistake: the help for imrotate should state which coordinate system it is assuming.