Can imregister provide transformation details on the registeration of the moving image?

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Sonoma Rich
Sonoma Rich on 19 Mar 2012
Commented: Alex Taylor on 21 Dec 2013
I want to register and fuse two images, but I need to do some image processing of the images that I register, then use the translation and rotation details of the registration to fuse the unprocessed images. imregister only provides a transformed image, but no details on how it transformed it. Is there any way to get the details of the transformation to apply to my unprocessed images?
  2 Comments
Sean de Wolski
Sean de Wolski on 27 Feb 2013
@Anita, I believe you just have to add tform as an output:
[moving_ref, tform] = imregister2(varargin)
Then copy the rest of its contents.

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Accepted Answer

Sonoma Rich
Sonoma Rich on 20 Mar 2012
I modified imregister to return the "tform" object that it uses for the transformation. I then created a copy of "transformMovingImage", a function within imregister so I can call it.
[optimizer, metric] = imregconfig('multimodal');
[movingRegisteredProcessed, tform] = imregister2(movingProcessed,fixedProcessed,'rigid',optimizer,metric);
movingRegisteredUnprocessed = MyTransformMovingImage(movingUnprocessed, fixedUnprocessed, tform);
fused_image = imfuse(fixedUnprocessed,movingRegisteredUnprocessed,'blend');
This worked. It would be nice if the standard function provided the "tform" object.

More Answers (2)

Alex Taylor
Alex Taylor on 14 Mar 2013
As of R2013a, users who want access to the geometric transformation estimate computed by imregister can call the function imregtform. The function imregtform returns a geometric transformation object that can be applied to the moving image using the new function imwarp.
The function imregister calls imregtform to obtain the geometric transformation that registers the moving image to the fixed image and then calls imwarp to produce the returned output image.
  3 Comments
Alex Taylor
Alex Taylor on 21 Dec 2013
Yes, I'm quite sure. When you call imwarp with the output tform, you will need to specify an 'outputview' so that imwarp knows the location and resolution you want for the resampled image. In most registration problems in the default coordinate system, you will define the output spatial referencing option (assuming 2d) as:
MovingReg = imwarp(moving, tform, 'OutputView', imref2d(size( fixed)));
This is shown in the examples in the help and documentation for imregtform.

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Ashish Uthama
Ashish Uthama on 20 Mar 2012
One possible approach:
If you add this parameter and value:
'DisplayOptimization',true
to your call, you'll notice that imregister displays the affine transform it uses with imtransform to perform the final registration.
  1 Comment
Sonoma Rich
Sonoma Rich on 20 Mar 2012
I tried this, but I need the results as an object that I can work with it. This method just displays the transformation details, but I need to copy and paste it to use it.

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