Abstract: Extraneous signals or artifacts are reduced in a multiple measurement noise reducing system such as an X-ray imaging system by processing a plurality of measurements to obtain a first image signal of an object representing a desired parameter such as a blood vessel, processing the plurality of measurements to provide a second image signal having increased signal-to-noise, low pass filtering the first image signal, high pass filtering the second image signal, and then combining the two filtered signals. The filter frequencies are varied in response to the presence of artifacts to minimize effects of the artifact on the combined signal.

Abstract: Disclosed is a multiple measurement multiple energy X-ray imaging system in which a plurality of measurements are processed to provide a first image signal representing a desired parameter of an object and in which the plurality of measurements are processed to provide a second processed image signal having greater signal-to-noise ratio than the first processed image signal but in which extraneous artifacts may be introduced into the signal. The spatial location of edges of the extraneous artifacts are determined. The first processed image signal and the second processed image signal are combined to provide an improved image signal except at the spatial locations of the extraneous artifacts where the first processed image signal is used for the image signal thereby eliminating the extraneous artifact from the displayed image.