Method and apparatus for accelerated elastic registration of multiple scans of internal properties of a body

An apparatus for elastic registration of multiple scans of internal properties of a body, comprising:

• a computer-readable memory for storing control point transformation data that indicates a vector φ of values for transform parameters for each control point of a plurality of control points that correspond to scan elements in a reference scan, wherein
• the vector φ of values for transform parameters for a particular control point indicates how to associate the particular control point with one or more scan elements in a floating scan different from the reference scan, and
• every scan element in the reference scan has a position indicated by a plurality of coordinate values for a corresponding plurality of dimensions;
• a first logic circuit, including a first register, configured for determining and storing in the first register, for a first subset of contiguous scan elements in the reference scan, a first cubic B-spline coefficient coef1=ΣB(w1) φ for a first coordinate value of a scan element in a distance w1 from a control point along a first dimension of the plurality of dimensions summed over four control points;
• and
• a second logic circuit, including a second register, configured for reading the first register and determining a plurality of cubic B-spline coefficients coef2=ΣB(w2) coef1 for a corresponding plurality of coordinate values of a plurality of scan elements in the first subset a distance w2 from a control point along a different second dimension of the plurality of dimensions each summed over four control points and storing the each coef2 value in succession in the second register,
• wherein
• the reference scan includes a plurality of subsets of contiguous scan elements in the reference scan and each subset is associated with only one control point, and
• B(n) is a well known function for contributions at an arbitrary point from a control point at a normalized distance n=d/s where d is the distance from the control point to the arbitrary point and s is the separation of adjacent control points that straddle the arbitrary point.

An apparatus for elastic registration of multiple scans of internal properties of a body, comprising:

• a computer-readable medium for storing:
• a two dimensional first joint histogram of mutual information based on reference scan data and floating scan data for a plurality of scan elements;
• and
• subvolume data that indicates a subset of contiguous scan elements of the plurality of scan elements,
• wherein
• reference scan data indicates for the plurality of scan elements a corresponding plurality of intensity values based on a first scan of the body,
• floating scan data indicates for the plurality of scan elements a corresponding plurality of intensity values based on a different second scan of the body and a first transformation for mapping coordinates of scan elements from the first scan to coordinates of scan elements in the second scan, and
• the joint histogram indicates a number of the plurality of scan elements that have intensity values based on the first scan in a first range of intensities and have intensity values based on the second scan in a second range of intensities;
• a logic circuit configured for determining a local joint histogram of mutual information based on the reference scan data and the floating scan data for the subset of contiguous scan elements;
• a logic circuit configured for determining a remainder joint histogram of mutual information by subtracting the local joint histogram from the first joint histogram and storing the remainder joint histogram on the computer-readable medium;
• and
• a logic circuit configured for determining a value for a similarity measure, based at least in part on the remainder joint histogram, for a second transformation for mapping coordinates of the subset of scan elements from the first scan to coordinates of scan elements in the second scan.

An apparatus for elastic registration of multiple scans of internal properties of a body, comprising:

• a computer-readable medium for storing a two dimensional joint histogram of mutual information based on reference scan data and floating scan data for a plurality of scan elements wherein
• reference scan data indicates for the plurality of scan elements a corresponding plurality of intensity values based on a first scan of the body,
• floating scan data indicates for the plurality of scan elements a corresponding plurality of intensity values based on a different second scan of the body and a first transformation for mapping coordinates of scan elements from the first scan to coordinates of scan elements in the second scan, and
• the joint histogram indicates a number of the plurality of scan elements that have intensity values based on the first scan in a first range of intensities and have intensity values based on the second scan in a second range of intensities;
• and
• a logic circuit configured for determining based on the joint histogram a measure of similarity for the reference scan data and the floating scan data, wherein the measure of similarity is not mutual information,
• whereby an elastic transformation can be determined based on the measure of similarity.