This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Fourier transform time and frequency domains. en visualization of the relationship between the time domain and the frequency domain of function based on its Fourier transform The Fourier transform takes an input function in red in the time domain and converts it into new function fhat in blue in the frequency domain In other words