AUTOMATIC IMAGE REGISTRATION 
by 
G. L. Hobrough and G. A. Wood 
The registration of photographic images, whether accomplished manually or 
automatically, is basic to practically all photogrammetric operations. The Itek 
Corporation is currently undertaking a development program leading to a complete 
photogrammetric system automated at key points by automatic-registration tech 
niques. It is the purpose of this paper to define image registration and to 
describe the operation of an automatic-registration viewer for vertical, con 
vergent, and panoramic stereograms. 
There are a few terms which in the interest of clarity probably require 
definition before proceeding: 
1. Transformation 
A systematic operation upon an image, thereby to alter its scale, orienta 
tion, or overall shape. 
Figure 1 illustrates the 10 first- and second-order transformations which 
are considered prime in this paper. Also shown are various combinations of 
these transformations, some of which are more familiar than those which we 
regard as prime. In this system of nomenclature relative displacement of an 
image is regarded as a zero-order transformation. 
Figure 1.- 
Prime transformations.