v3reg − register two 3-D images by correlation

v3pol [if=<inputfile>] [ig=<inputfile2>] [of=<outputfile>] d=<dimlist> [-s] [-d] [-v]

V3reg registers two 3D images. The maximum displacement permitted in each dimension is specified by the d= parameter. A static region of the first image is matched to various locations of a region of the second image. The regions are the largest possible within the constraints of the search space specified by the d= parameters and the sizes of the two images.

There are two modes of operation: correlation mode and search mode. The default is the correlation mode in which a cross correlation matrix of the size specified by the d= parameter is output.

The search mode is selected by the -s option. In this mode the algorithm starts in the center of the search region and, in each iteration moves to the highest cross correlation in the immediate 3x3x3 neighborhood. The algorithm iterates until either a local maximum in the cross correlation is found or until the boundary of the search region is reached. The two matching image regions are then output, the second image region is shifted so as to be aligned with the first image region.

The images must have the same base type but not have to have the same size. Only float images are currently supported.

if=<fname>

Input image.

ig=<fname>

The second required input image

d=<x>,<y>,<z>

This required option specifies the distance that will be searched for each direction. The bounding box of the search matrix is -x,xi+1, -y,y+1 -z,z+1.

-s

The -s option selects the search mode where a simple adjacent neighbor maximum correlation search is made to identify the best registered location.

-2d

For the search mode this option constrains the search to just two dimensions x and y. This option can also be used to register two 2D images.

-d

For the search mode this option outputs a difference image rather than the matched regions of the two input images.

-v

selects the verbose mode and prints some information about its action.

A. P. Reeves