Complex Image Set

A complex image set cannot be represented by a single grid. Instead it is made up of multiple grids, because it includes things like:

1. gantry tilt
2. irregular slice spacing
3. overlapping scans

Proposed data structure shown in pseudocode

ImageCollection {
 // The reformatted image is a standard itk image.  It has uniform spacing & direction cosines.
 // It can be NULL if the collection has not yet been formatted.
 itkOrientedImage ReformattedImage;
 // The group array is an array of image sections.  Each image 
 ImageGroupArray {
   // ImageGroups are image sections with the same spacing, gantry tilt, etc.
   ImageGroup[0]
   ImageGroup[1]
   ...
}

Normal ITK routines will operate on the reformatted image (e.g. by making the ImageCollection a subclass of itkOrientedImage). But if the user needs the original images or their headers, they are available.