System and method for dynamic background subtraction

Abstract

An image acquisition system and method for generating a subtracted image motion picture as an imaging device moves relative to a subject includes an imaging device for first generating a sequence of first image frames as the imaging device moves along an imaging path under operator control and later generating a sequence of second image frames as the imaging device automatically moves along the same imaging path under processor control. Motion along the imaging path can be duplicated by sensing and storing information indicative of the position of the imaging device relative to the subject as a function of time and later commanding servo motors connected to the imaging device using that position information. Each frame in the first and second sequence of frames has position information stored therewith identifying the location along the imaging path at which each frame was generated. The first and second sequence of frames may then be aligned using the position information and subtracted on a frame-by-frame basis to obtain a subtraction image motion picture essentially free of background interference to detect change over time. The first and second motion pictures may be made at different points of time under similar circumstances either with or without the use of a contrast medium, and subtracted to obtain a difference picture to highlight changes over time.