Fig 4. A line segment AB observed by a camera.
Distance Δy is the height of this line segment seen by a camera; za and zb are the distances of the vertices A and B from the camera, respectively, and α is the camera tilt angle.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.