A system determines static background medical image data by receiving pixel luminance data comprising multiple sequential medical images of a patient anatomical portion and luminance data of an individual image that comprises multiple pixel luminance representative values of multiple individual pixels of the individual image. A filter includes a first filter function having a first response time for filtering received luminance representative values of a particular individual pixel varying in response to a first motion disturbance in the multiple sequential medical images for use in identifying a substantially minimum luminance value of the particular individual pixel in the multiple sequential medical images. The filter filters luminance representative values of individual pixels of the multiple sequential medical images to identify substantially minimum luminance values of individual pixels in the multiple sequential medical images as background image data of the multiple sequential medical images.