1. A method comprising a plurality of activities comprising: receiving a first image of a predetermined physiological structure of a patient, said first image originated from an X-ray device operated at a first energy spectrum, said first image originated during a first time interval; receiving a second image of said predetermined physiological structure of said patient, said second image originated from said X-ray device operated at a second energy spectrum, said second image originated during a second time interval, said second time interval distinct from said first time interval; automatically determining an initial estimate of a movement of said patient in said second time interval relative to said first time interval via a corner matching based registration, said corner matching based registration determined via: defining a first Gaussian pyramid associated with said first image and a second Gaussian pyramid associated with said second image, said first Gaussian pyramid comprising a plurality of layers, said second Gaussian pyramid comprising a plurality of layers; calculating a first corner strength map associated with said first image; calculating a second corner strength map associated with said second image; initializing a rectangular mesh associated with each layer of said first Gaussian pyramid; for each control point in each rectangular mesh on a lowest resolution layer, determining a point with a largest corner strength in a defined neighborhood and define said point with said largest corner strength as said control point; for each control point of each mesh on a lowest resolution layer in said first Gaussian pyramid, determining a corresponding control point in a corresponding layer in said second Gaussian pyramid; and generating a corresponding mesh on each layer of said second Gaussian pyramid to each mesh associated with each layer of said first Gaussian pyramid; automatically determining an improved estimate of said movement of said patient in said second time interval relative to said first time interval based upon said initial estimate of said movement, said improved estimate obtained via an iterative hierarchical structured intensity comparison between said first Gaussian pyramid and said second Gaussian pyramid, said iterative hierarchical structured intensity comparison comprising, from a lowest resolution layer to a highest resolution layer of said first Gaussian pyramid and said second Gaussian pyramid: defining a region-based, intensity invariant similarity measurement between said first image and said second image; estimating an optimal deformation, associated with each control point, that attempts to maximize a similarity between said first image and said second image by searching within a neighborhood of each control point; map an adjusted mesh of each layer to a next higher resolution layer to obtain an initial control point associated with said next higher resolution layer; and repeat said automatically determining said improved estimate activity for each resolution layer until said highest resolution layer is aligned; achieving subpixel accuracy by searching within said neighborhood associated with each control point by utilizing a resolution level step size smaller than approximately one pixel on said highest resolution layer; based on said estimated optimal deformation for each control point, automatically estimating a soft-tissue layer image and a bone layer image of said predetermined physiological structures of said patient; and automatically rendering said estimated soft-tissue layer image and said estimated bone layer image of said predetermined physiological structures of said patient.