Described here are a system and method for producing a statistical noise map that indicates the noise present in data acquired with an x-ray imaging system, such as an x-ray computed tomography system, an x-ray tomosynthesis system, a C-arm x-ray imaging system, and so on. In general, an image is reconstructed from the acquired data using, for example, any standard filtered back projection (“FBP”) image reconstruction algorithm. This image is used as a base line to estimate a noise standard distribution map. The raw projection data represents a typical measurement among many repeated measurements under the same experimental conditions therefore, the measured projection data can be used to numerically generate an ensemble of many (e.g., twenty or more) noisy projection data sets. These noisy projection data sets are then used to reconstruct noisy images and from these noisy images and the original image, the statistical noise map can be computed.