UNIVERSAL ELECTRONIC RECTIFIER 
The Electronic Rectifier represents a significant advancement in 
photographic rectification equipment. The instrument described is univer- 
sally adapted for use with a wide variety of aerial photography. Frame 
photographs with formats up to 9 inches by 18 inches and focal lengths 
from 3 inches to 100 inches can be accommodated, Oblique aerial nega- 
tives ranging from o? to 80? can be readily restituted, The instrument 
employs.a unique optical-mechanical scanning technique and an Ultrasonic 
Light Modulator to produce accurate rectified photographic prints. With 
slight modification the Electronic Rectifier can be designed to accommodate 
up to 9 inch wide panoramic photographye 
Herein is described, the general characteristics of the Electronic 
Rectifier developed by the Fairchild Graphic Corp, under the technical 
direction of the Rome Air Development Center, Air Research and Development 
Command, USAF. 
In the transformation of picture elements, from a tilted plane to a 
rectified plane it can be shown in Fig #1 that the transformation is linear 
along a line perpendicular to the principle line. In Fig #1 the horizontal 
plane represents the ground. The tilted photo plane is projected to the 
ground so that the principle point in the photo coinciaes with its position 
on the ground. From this, the transformation equations become: 
U = uf cos t (1) 
f cos t « v sin t 
V = fv ( 
f eos tl —v.sin 1 
na 
f 
  
Spread through a number of years.