# How to convert a spatial frequency in a 2D-DFT into the units radians per pixel?

Let's say I have a 2D image, and I take the discrete Fourier Transform (via FFT) of that image. In the frequency domain, I get the following image:

In this image, let's just assume all the spatial frequencies are zero, except for the selected point at (608, 513). Now, given the x and y-coordinate of the spatial frequency (note this has been centered via fftshift), how can I convert the spatial frequency for this selected pixel into radians per pixel?

My Guess: Since the 2D-DFT is centered, our X spatial frequency is 608-513 = 95, and our Y spatial frequency is 513-513 = 0. Then, we need to multiply by 95 by 2 * pi and divide by N to get radians per pixel?