How to find the symmetry axis of an Image?

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

Answer 1

[Matt J]

Assuming you have the Image Processing toolbox, you could use REGIONPROPS(...,'Orientation').

Answer 2

[Image Analyst]

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.

[Richa Nayak]

I am using R2010 version.

[Image Analyst]

Upgrade and you'll solve your problem.

[Matt J]

Or, try REGIONPROPS, as I suggested initially. It's available in R2010.

[Image Analyst]

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]

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?