Coordinate Systems
Example 1.1: MeVisLab Coordinate Systems Three coordinate systems exist next to each other:
World coordinates Voxel coordinates Device coordinates World coordinate systems in MeVisLab are always right handed.
The blue rectangle shows the same region in the three coordinate systems.
Coordinate Systems in MeVisLab World coordinates World coordinates are:
Global: Combine several objects in a view Isotropic: All directions are equivalent Orthogonal: Coordinate axes are orthogonal to each other The origin of the world coordinate system can be anywhere and is not clearly defined.
Example 1.2: DICOM Coordinate Systems General Coordinate systems in DICOM are basically the same as world coordinates in MeVisLab (except for the 0.5 voxel offset). World coordinates also refer to the patient axes. They are:
Based on the patient’s main body axes (transverse, coronal, sagittal) Measured as 1 coordinate unit = 1 millimeter Right-handed Not standardized regarding their origin World Coordinates in Context of the Human Body The DICOM (Digital Imaging and Communications in Medicine) standard defines a data format that groups information into data sets.
