Rotated Image VOI

A rotated Volume Of Interest is useful in many situations. It can be defined interactively with XF.Interactive.DefineRotatedImageVOI.

For example a scanned sample might be slightly oblique or oriented in a different way than other samples. Or a specific sub-region to be analysed is not aligned with the main axes.

Interactive User Interface

  • The ‘’Finish Job’’ button completes the interactive step once the VOI has been selected.

  • The ‘’Cancel Job’’ button closes the UI for now, without completing the step.

  • The ‘’Update Template’’ button remembers the current VOI as a template starting point for future runs.

  • The ‘’Restore Previous’’ button restores the VOI from the previous job if it has already been completed before. This is useful for later adjustments.

  • Numerical coordinates can be entered in the left sidebar.

  • The white box can be moved interactively.

  • The square corner handles resize the box.

  • The circular corner handles rotate the box.

  • The CTRL key can be used with the square handles to resize without changing the aspect ratio.

  • The CTRL key can be used with the circular handles to resize and rotate at the same time.

  • In the 3D view the right mouse button can be used to freely drag-rotate in all directions.

  • The ‘’Reset’’ button can be used to start over completely, or to reset only the rotation or only the size independently.

  • The ‘’Isotropic’’ button can be used to revert to a cubic voxel size. This is often required because interactive resizing leads to non-uniform aspect ratios.

  • The task input force_isotropic can also be configured to automatically enforce this when finishing the job.


A new image can then be created (cropped) using Lucid.Core.CropRotatedImageVOI.

For binary masks the nearest method is often preferable, while the trilinear is better for grayscale images.

Adjusting and Inverting

Lucid.Util.AdjustRotatedImageVOI is useful to move or resize a VOI automatically, for example to evaluate a second adjacent region.

Lucid.Util.RotatedImageVOIInverted is useful to transform a smaller crop back to the original space.

Automatic Task Types

It is also possible to automatically create a RotatedImageVOI object from a processing task types. Examples of this are:

  • Lucid.Util.RotatedImageVOIFromRegistrationPoints

  • Lucid.Core.MomentOfInertiaTensor

These can also be used to set the initial VOI passed into the interactive UI task as a starting point.