An official website of the United States government
Here's how you know
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.
Radial distribution of analysed structures calculated by Fourier transformation corresponding to their dimensions. The x-axis represents defined bands of spatial frequencies. The y-axis represents the amplitude of particular frequency bands. We defined 20 bands of spatial frequency.