How can I get the DC/AC for an image?

I want to get DC and AC component of Fourier transform of an image. And calculate their ratio.

Answer 1

[Walter Roberson]

fft of a vector returns a vector. The first element of that output vector is the sum of the DC component over vector. The other elements are the AC components.

Another way of calculating the DC component is mean()

[Hossain Md Shakhawat]

solved it