fsl.data.constants

This module defines some constant values used throughout fslpy.

The following constants relate to the orientation of an axis, in either voxel or world space:

ORIENT_L2R	The axis goes from left to right.
ORIENT_R2L	The axis goes from right to left.
ORIENT_P2A	The axis goes from posterior to anterior.
ORIENT_A2P	The axis goes from anterior to posterior.
ORIENT_I2S	The axis goes from inferior to superior.
ORIENT_S2I	The axis goes from superior to inferior.
ORIENT_UNKNOWN	The axis has an unknown orientation.

These constants relate to the space in which a NIFTI image is assumed to be (i.e. the transformed coordinate space); they are defined in the NIFTI specification:

NIFTI_XFORM_UNKNOWN	Arbitrary coordinates.
NIFTI_XFORM_SCANNER_ANAT	Scanner-based anatomical coordinates.
NIFTI_XFORM_ALIGNED_ANAT	Coordinates aligned to another file's, or to anatomical "truth".
NIFTI_XFORM_TALAIRACH	Coordinates aligned to Talairach-Tournoux Atlas; (0,0,0)=AC, etc.
NIFTI_XFORM_MNI_152	MNI 152 normalized coordinates.
NIFTI_XFORM_TEMPLATE_OTHER	Coordinates aligned to some template that is not MNI152 or Talairach.

fsl.data.constants.ORIENT_L2R = 0

The axis goes from left to right.

fsl.data.constants.ORIENT_R2L = 1

The axis goes from right to left.

fsl.data.constants.ORIENT_P2A = 2

The axis goes from posterior to anterior.

fsl.data.constants.ORIENT_A2P = 3

The axis goes from anterior to posterior.

fsl.data.constants.ORIENT_I2S = 4

The axis goes from inferior to superior.

fsl.data.constants.ORIENT_S2I = 5

The axis goes from superior to inferior.

fsl.data.constants.ORIENT_UNKNOWN = -1

The axis has an unknown orientation.

fsl.data.constants.NIFTI_XFORM_UNKNOWN = 0

Arbitrary coordinates.

fsl.data.constants.NIFTI_XFORM_SCANNER_ANAT = 1

Scanner-based anatomical coordinates.

fsl.data.constants.NIFTI_XFORM_ALIGNED_ANAT = 2

Coordinates aligned to another file’s, or to anatomical “truth”.

fsl.data.constants.NIFTI_XFORM_TALAIRACH = 3

Coordinates aligned to Talairach-Tournoux Atlas; (0,0,0)=AC, etc.

fsl.data.constants.NIFTI_XFORM_MNI_152 = 4

MNI 152 normalized coordinates.

fsl.data.constants.NIFTI_XFORM_TEMPLATE_OTHER = 5

Coordinates aligned to some template that is not MNI152 or Talairach.

See https://www.nitrc.org/forum/message.php?msg_id=26394 for details.

fsl.data.constants.NIFTI_XFORM_ANALYZE = 6

Code which indicates that this is an ANALYZE image, not a NIFTI image.