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.
Images of the platform in different ray directions: (a) image under strong supplementary light source condition; (b) image under strong natural light conditions; (c) Images under low natural light conditions; (d) image under weak supplementary light source condition.
