Orfeo Toolbox
4.0

The itk::BloxImage object is a regular, rectilinear lattice of blocks'' in ndimensional space. The word
blox'' was chosen to bring to mind a set of city blocks'' in 2D or
building blocks'' in 3D. Being a regular lattice, itk::BloxImage logically derives from itkImage. In an itk::BloxImage, each pixel represents an isometric spacefilling block of geometric space, called an itk::BloxPixel. Each itk::BloxPixel generally covers many pixels in the underlying image and is used to store a variable number of image primitives (such as boundary points) or features (such as medial nodes) gathered within that region of geometric space. To do this, each itk::BloxPixel contains a linked list.
The itk::BloxImage object facilitates certain forms of analysis by providing geometric hashing. For example, if boundary points are stored in an itk::BloxImage, pairs of boundary points that face each other (called ``core atoms'') can be found by searching relatively small regions of geometric space that face each boundary point for appropriate mates. Because an itk::BloxImage is rectilinear in geometric space (even though the underlying image may not be) subsequent analysis can be invariant to rotation and translation.