How to find the symmetry axis of an Image?

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Richa Nayak
Richa Nayak on 30 Sep 2012
The image is rotated 60 degrees, gray scale*,.tiff format*. I want find its symmetry axis to rotate it to 0 degrees. I am using MATLAB R2010

Answers (2)

Matt J
Matt J on 30 Sep 2012
Assuming you have the Image Processing toolbox, you could use REGIONPROPS(...,'Orientation').

Image Analyst
Image Analyst on 30 Sep 2012
Edited: Image Analyst on 30 Sep 2012
If you have a recent (R2012a or later, I think) Image Processing Toolbox, you can use imregister(). See their example on http://www.mathworks.com/help/images/ref/imregister.html - it does just that.
  5 Comments
Image Analyst
Image Analyst on 3 Oct 2012
Edited: Image Analyst on 3 Oct 2012
I'm not quite sure how regionprops could be used. Could you give a short demo? To take into account the entire image, the binary image (or labeled image) would have to be the entire image, and then the orientation would not be different for different images because the binary image would be the same for all images. Perhaps I'm just overlooking something.
Matt J
Matt J on 3 Oct 2012
Edited: Matt J on 3 Oct 2012
Gosh, I hadn't noticed that REGIONPROPS(...,'Orientation') doesn't incorporate the intensity image distribution into its calculations. That seems pretty bizarre, no? Why do so for 'WeightedCentroid', which you would obviously use to get translational position, but not offer proper intensity moment calculations to get orientation?

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