Volocity - Alignment tool

Technical Note: 257
Reads: 6989
Creation Date: 23/10/2001
Modification Date: 12/02/2004

The Volocity alignment tool is designed to compensate for rotational and translational shifts between the two-dimensional planes that make up a volume.

When performing rotational correction the alignment module will search for correlation +/- 30 degrees from the origin.

The Alignment tool searches for correlation between slices in the data to match features and establish where each slice should be in relation to the next. For alignment to be successful features must be represented in neighboring slices ie the slices need to be similar.

The alignment tool will not be able to perform on structures which are, or approximate to, spheres since they show rotational symmetry which makes feature matching impossible.

During rotation of images anti-aliasing is applied which has a smoothing effect on the data.

Alignment operates on individual volumes, and volume sequences, not 2 dimensional data. Select volume or volumes, or channels within a volume sequence, to be aligned and select "Align Volume" from the "Tools" menu.

The original data is not overwritten, a new image or image sequence is created with the suffix (aligned).

There is no benefit to be gain by repeatedly aligning the same data.

The XY dimensions of an aligned volume will be the same as the original volume, areas of image that have been shifted outside the original boundary to allow alignment will be cropped from the result.