Abstract: A method for converting digital images of an actuated breast into an accurate description of breast surface motion from a digital image-based elasto-tomography system comprises the steps of artificially placing a high density of fiducial markers on the breast surface, whereby the fiducial markers have different qualities and are placed in different proportions according to their quality; utilizing motion invariant properties of the fiducial markers to form a global motion invariant signature; tracking the markers on the actuated breast surface from image to image in each digital camera using the global motion invariant signature; and using the cameras calibration to measure the breast surface motion.