Method and device for elastic registration between a two-dimensional digital image and a slice of a three-dimensional volume with overlapping content

A programmable device for elastic registration of a two-dimensional source digital image of an object of interest with a slice of a three dimensional target volume of the object of interest, comprising a computing unit adapted to implement a method comprising defining a Markov Random Field framework comprising at least one undirected pairwise graph superimposed on the two-dimensional image domain comprising at least a set of regular vertices and at least a set of edges, defining at least a grid of control points, each control point corresponding to a vertex of the set of vertices, and a neighborhood system of edges associated with vertices,

• the device being characterized in that it comprises:
• a defining unit for defining a set of multi-dimensional labels of a discrete space to associate to each control point, wherein a spatially displaced control point is obtained by assigning a given label to said control point, a control point displacement defining a transformation adapted to obtain a plane slice of the target volume and an in-plane deformation transformation of the source digital image,
• an obtaining unit for obtaining a set of labels defining a set of displaced control points, by minimizing an energy target function, the set of displaced control points defining a plane slice of the target volume that elastically matches the two-dimensional source digital image according to the energy target function,
• the energy target function being expressed as a sum of terms including:
• at least one first order term computed as a sum, over the control points, of unary potentials depending on the vertex multi-dimensional label, and/or
• at least one second order term computed as a sum, over the pairs of control points according to a second order neighborhood system, of pairwise potentials depending on pairs of multi-dimensional labels of two connected vertices, and/or
• at least one higher order term, over higher order cliques of control points according to a higher order neighborhood system, of higher order potentials depending on a number of labels depending on the order of said cliques.

A non-transitory program storage device readable by a processing system, tangibly embodying a program of instructions executed by the processing system to perform the method steps for elastic registration of a two-dimensional source digital image of an object of interest with a slice of a three dimensional target volume of the object of interest, the method comprising defining a Markov Random Field framework comprising at least one undirected pairwise graph superimposed on the two-dimensional image domain comprising at least a set of regular vertices and at least a set of edges, defining at least a grid of control points, each control point corresponding to a vertex of the set of vertices, and a neighborhood system of edges associated with vertices,

• the method being characterized in that it comprises:
• defining a set of multi-dimensional labels of a discrete space to associate to each control point, wherein a spatially displaced control point is obtained by assigning a given label to said control point, a control point displacement defining a transformation adapted to obtain a plane slice of the target volume and an in-plane deformation transformation of the source digital image,
• obtaining a set of labels defining a set of displaced control points, by minimizing an energy target function, the set of displaced control points defining a plane slice of the target volume that elastically matches the two-dimensional source digital image according to the energy target function,
• the energy target function being expressed as a sum of terms including:
• at least one first order term computed as a sum, over the control points, of unary potentials depending on the vertex multi-dimensional label, and/or
• at least one second order term computed as a sum, over the pairs of control points according to a second order neighborhood system, of pairwise potentials depending on pairs of multi-dimensional labels of two connected vertices, and/or
• at least one higher order term, over higher order cliques of control points according to a higher order neighborhood system, of higher order potentials depending on a number of labels depending on the order of said cliques.