In MeVisLab, three coordinate systems exist next to each other:

World coordinates

Voxel coordinates

Device coordinates

The blue rectangle shows the same region in the three coordinate systems.

World coordinates are:

Global: Combine several objects in a view

Absolute: Measure distances and angles

Isotropic: All directions are equivalent

Orthogonal: Coordinate axes are orthogonal to each other

Voxel coordinates are:

Relative to an image

Dependent on voxel spacing

Continuous from [0..x,0..y,0..z], voxel center at 0.5

Often non-isotropic, sometimes non-orthogonal

Direct relation to voxel location in memory

Device coordinates are:

2D coordinates in OpenGL viewport

Measured in pixel

Have their origin (0,0) in the top left corner of the device (with x-coordinates increasing to the right and y-coordinates increasing downwards)

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