1. A method for producing a statistical noise map using an x-ray imaging system, the steps of the method comprising: a) acquiring data with the x-ray imaging system, the acquired data indicating a count of photons detected by the x-ray imaging system; b) reconstructing an image from the data acquired in step a); c) forming noisy data by adding statistical noise to the data acquired in step a); d) reconstructing a noisy image from the noisy data formed in step c); and e) producing a statistical noise map by subtracting the image reconstructed in step b) and the noisy image reconstructed in step d).