# DICOM Standard Browser

Built with by Innolitics, a team of medical imaging software developers.

Data synced with official DICOM standard on 12 May 2020. The DICOM Standard is under continuous maintenance, and the current official version is available at http://www.dicomstandard.org/current/. DICOM Parts 3, 4, and 6, © NEMA. Please note that the most recent PDF version of the standard is the official reference, and should checked when making technical decisions.

## Frame of Reference Transformation Matrix Type Attribute

Tag (0070,030C) Required (1) FrameOfReferenceTransformationMatrixType 1 Code String (CS)

Type of Frame of Reference Transformation Matrix (3006,00C6).

Enumerated Values:

RIGID

RIGID_SCALE

AFFINE

See Section C.20.2.1.2

## Section C.20.2.1.2

##### C.20.2.1.2 Frame of Reference Transformation Matrix Type

There are three types of Registration Matrices:

RIGID: This is a registration involving only translations and rotations. Mathematically, the matrix is constrained to be orthonormal and describes six degrees of freedom: three translations, and three rotations.

RIGID_SCALE: This is a registration involving only translations, rotations and scaling. Mathematically, the matrix is constrained to be orthogonal and describes nine degrees of freedom: three translations, three rotations and three scales. This type of transformation is sometimes used in atlas mapping.

AFFINE: This is a registration involving translations, rotations, scaling and shearing. Mathematically, there are no constraints on the elements of the Frame of Reference Transformation Matrix other than that the last row shall be (0,0,0,1) to preserve the homogeneous coordinates, so it conveys twelve degrees of freedom. This type of transformation is sometimes used in atlas mapping.

See Annex P “Transforms and Mappings (Informative)” in PS3.17 for more detail.