Definition: (DOD, NATO) The foot of the perpendicular to the photo plane through the perspective center. Generally determined by intersection of the lines joining opposite collimating or fiducial marks.
principal point
From Department of Defense, for About.com
More of This Feature
Explore US Military
Must Reads
About.com Special Features
Make Meals Easy
An easy way to put delicious meals together.Build Your Business
Get tips on starting up and staying competitive.Love Your Living Space
Achieve your dream home with advice from the pros.Financial Planning
Stay on top with our smart financial tips.
©2009 About.com, a part of The New York Times Company.
All rights reserved.