How to use "imregister" with "InitialTransformation"?

Hi everyone,

I try to use imregister with intialization:

% im:           3D image to be registered 
% fixed:        3D Reference image
% [optimizer, metric]  = imregconfig('monomodal');
% R_reg_old:    an imreg3d object
[movingRegistered, R_reg] = imregister(im,fixed,'rigid',optimizer, metric,'InitialTransformation',R_reg_old);

But I get this error:

Error using imregtform>preparseSpatialRefObjects (line 492)

Expected spatial referencing arguments to be 2nd and 4th input arguments.

Error in imregtform>parseInputs (line 243)

[R_moving,R_fixed,varargin] = preparseSpatialRefObjects(varargin{:});

Error in imregtform (line 124)

parsedInputs = parseInputs(varargin{:});

Error in imregister (line 119)

tform = imregtform(varargin{:});

I checked the document of imregister: https://www.mathworks.com/help/images/ref/imregister.html

But I still don't understand why I got this error. Can anyone help me with this?

Thank you so much!

Answer 1

[Steve Eddins]

The value of InitialTransformation is supposed to be an affine3d object, not an imref3d object. See the doc description for the InitialTransformation input.