[Insight-users] Re: registration

[Moti Freiman]

Hi,
Below is some code I wrote to translate a versor rigid 3d transform to
angles (rotation about x,y,z, in radians) and translations.
You can find an explantion about these equations in:
http://isiswiki.georgetown.edu/zivy/writtenMaterial/frames.pdf
Note that this transform assume that the rotations and translations is about
the origin of the image.

Moti

//**************************** code
********************************************************************************

const TransformType::ParametersType& finalParameters =
_transform->GetParameters ();

TransformType::MatrixType rot_matrix = _transform->GetRotationMatrix ();

_finalParams[1] = atan2 (-rot_matrix[2][0], sqrt
(rot_matrix[0][0]*rot_matrix[0][0] + rot_matrix[1][0]*rot_matrix[1][0]));
//Ry

_finalParams[2] = atan2 (rot_matrix[2][0]/cos (_finalParams[1]),
rot_matrix[0][0]/cos (_finalParams[1]));//Rz

_finalParams[0] = atan2 (rot_matrix[2][1]/cos (_finalParams[1]),
rot_matrix[2][2]/cos (_finalParams[1]));//Rz

_finalParams [3] = finalParameters[3]; //Tx

_finalParams [4] = finalParameters[4]; //Ty

_finalParams [5] = finalParameters[5]; //Tz



//**************************** end of code
********************************************************************************


-- 
__
Moti Freiman, Ph.D Student.
Medical Image Processing and Computer-Assisted Surgery Laboratory.
School of Computer Science and Engineering.
The Hebrew University of Jerusalem Givat Ram, Jerusalem 91904, Israel
Phone: +(972)-2-658-5371 (laboratory)
WWW site: http://www.cs.huji.ac.il/~freiman
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