How to get spectrum of an image?

1. How to calculate power spectrum of an image?
2. What is the spectrum of an image?

How to calculate power spectrum of an image?

Finally, we calculated the power spectrum S of each image as the square amplitude of the Fourier transform: Eq. (3)(3) S(u,v)= 1 L |F( u,v )| 2 Γ(u,v) , with Γ the correction factor mentioned above, and L the number of pixels in the image (L = 541 × 512).

What is the spectrum of an image?

Frequency spectrum of a 2D image is a discrete Fourier transform of the image performed to obtain decomposition of the signal into different frequency bands.