NAME

       AverageAffineTransform - part of ANTS registration suite

DESCRIPTION

       AverageAffineTransform          ImageDimension         output_affine_transform         [-R
       reference_affine_transform] {[-i] affine_transform_txt [weight(=1)] ]}

              Usage: Compute weighted average of input affine transforms.

       For 2D and 3D transform, the affine transform is first decomposed into scale x shearing  x
       rotation.  Then  these parameters are averaged, using the weights if they provided. For 3D
       transform, the rotation component is the quaternion. After averaging, the quaternion  will
       also  be  normalized  to  have  unit norm. For 2D transform, the rotation component is the
       rotation angle. The weight for each transform is a non-negative number.  The  sum  of  all
       weights  will  be  normalized  to 1 before averaging. The default value for each weight is
       1.0.

       All  affine  transforms  is  a  "centerd"   transform,   following   ITK   convention.   A
       reference_affine_transform defines the center for the output transform. The first provided
       transform  is  the  default   reference   transform   Output   affine   transform   is   a
       MatrixOffsetBaseTransform.

       -i option takes the inverse of the affine mapping.

              For  example:  2  output_affine.txt -R A.txt A1.txt 1.0 -i A2.txt 2.0 A3.txt A4.txt
              6.0 A5.txt

       This computes: (1*A1 + 2*(A2)^-1 + A3 + A4*6 + A5 ) / (1+2+1+6+5)