Patent Document ID: 8358818
Application ID: 11985526
Patent Status: 1

Claim One:
1. A method of surface registration in image guided surgery, comprising the steps of: a. preoperatively acquiring an image of an organ of interest of a living subject; b. generating a first surface of the organ of interest of the living subject from the preoperatively acquired image; c. designating a set of target points, T={tn}, n=1, 2, 3,. .. , NT, from the first surface of the organ of interest, wherein the set of target points T contains one or more patch points corresponding to homologous anatomical features of the first surface of the organ of interest, and wherein each of the set of target points tm is indexed with a binary index, pTm, such that when pTm=0, the target point tm is a non-patch point, and when pTm=1, the target point tm is a patch point, the one or more patch points of the target points define a particular salient anatomical feature of the first surface of the organ of interest; d. intraoperatively acquiring an incomplete image of the organ of interest of the living subject; e. generating a second surface of the organ of interest of the living subject from the intraoperatively acquired incomplete image, wherein the second surface is an incomplete surface of the organ of interest of the living subject; f. designating a set of source points, S={sm}, m=1, 2, 3,. .. , NS, from the second surface of the organ of interest, wherein the set of source points S contain one or more patch points corresponding to homologous anatomical features of the second surface of the organ of interest, which is related to the corresponding homologous anatomical features of the first surface of the organ of interest, and wherein each of the set of source points sm is indexed with a binary index, pSm, such that when pSm=0, the source point sm is a non-patch point, and when pSm=1, the source point sm is a patch point, the one or more patch points of the source points define a particular salient anatomical feature of the second surface of the organ of interest; g. determining a point correspondence between the set of source points S and the set of target points T, whereby a closest point operator, C={Cm} is determined; h. biasing the point correspondence between the one or more source patch points and the one or more target patch points by a weighting factor, wPC, so as to assign weighted correspendence of a weighted point-based registration to the particular salient anatomical features and to bias the closest point operator Cm, via the following relationship: d m. n = { w PC ⁢  s m - t n  if ⁢ ⁢ p m S = p n T = 1  s m - t n  otherwise wherein 0<wPC<<1, dm,n is Euclidian distance between a source point sm and a target point tn; i. aligning the second surface of the organ of interest to the first surface of the organ of interest using the weighted point-based registration (PBR) between the set of source points S and the set of target points T by finding a rigid-body transformation (Ω) between the set of source points and the set of target points that minimizes an objective function of: f ⁡ ( Ω ) = ∑ m = 1 N M ⁢ ⁢ w m ⁢  C m ⁡ ( s m , T ) - Ω ⁡ ( s m )  2 wherein {wm} is a set of weights letting wm=1 for pSm=0 and wm=WPBR for pSm=1, and wherein WPBR is a function of iteration, i, in the form of: 
 W PBR ( i )= W PBR,base +[W PBR,max −W PBR,base ]exp[−α( i− 1)] wherein i=1, 2, 3,. .. N, N being the number of iteration, WPBR,max is a maximum patch weight factor and corresponds a patch weight at a first iteration, WPBR,base is a baseline patch weight factor, with 1≦WPBR,base ≦WPBR,max, and α is a relaxation constant with 0≦α≦1, wherein the aligned second surface of the organ of interest up; and j. repeating steps (f)-(i) using the aligned second surface of the organ of interest until the root mean square (RMS) closest point distances between the source and target points have reached a predetermined value.