Assume the following:
img = 255*rand(512); %Generating a 2D matrix with random numbers between 0 to 255.
fftimg = abs(fft2(img)); %FFT of the image.
The frequency transform of this image is a single high value at the top left corner of the image. This means the 'energy' or the frequency response is the highest and concentrated at the lowest frequency
Can you explain why this happens?