Systems and methods for negative registration of bone surfaces
Systems and methods for bone surface geometry generation include a computing device. The computing device projects first geometry data indicative of a first bone-contacting surface of a first bone of a patient to a coordinate space of a second bone of the patient to generate projected geometry. The second bone includes a second bone-contacting surface that interfaces with the first bone-contacting surface. The computing device also maps the projected geometry to a plurality of poses in a range of motion of the first bone relative to the second bone using position data indicative of relative positions of the first bone and the second bone at the plurality of poses in the range of motion. The computing device further selects intersecting geometry from the mapped, projected geometry to generate second geometry data indicative of the second bone-contacting surface.
1 . A method for bone surface geometry generation, the method comprising:
projecting, by a computing device, first geometry data indicative of a first bone-contacting surface of a first bone of a patient to a coordinate space of a second bone of the patient to generate projected geometry, wherein the second bone includes a second bone-contacting surface that interfaces with the first bone-contacting surface;
mapping, by the computing device, the projected geometry to a plurality of poses in a range of motion of the first bone relative to the second bone using position data indicative of relative positions of the first bone and the second bone at the plurality of poses in the range of motion; and
selecting, by the computing device, intersecting geometry from the mapped, projected geometry to generate second geometry data indicative of the second bone-contacting surface;
wherein projecting the first geometry data to the coordinate space comprises projecting the first geometry data to a cylindrical coordinate space having a first axis indicative of a linear position along a first imaginary axis relative to the first bone and a second axis indicative of an angle of rotation of the first bone relative to the second bone.
2 . The method of claim 1 , further comprising:
capturing, by the computing device, coordinate data indicative of the first bone-contacting surface; and
generating, by the computing device, the first geometry data based on the coordinate data.
3 . The method of claim 2 , further comprising capturing, by the computing device, the position data indicative of relative positions of the first bone and the second bone at the plurality of poses in the range of motion.
4 . The method of claim 2 , wherein capturing the coordinate data comprises receiving point data associated with a location of a registration tool having a pointer in contact with the first bone-contacting surface.
5 . The method of claim 2 , wherein capturing the coordinate data comprises receiving surface scan data from a laser scanner, a white light scanner, or a structured light scanner.
6 . The method of claim 2 , wherein capturing the coordinate data comprises receiving volumetric scan data from an ultrasound scanner.
7 . The method of claim 1 , wherein the first axis of the cylindrical coordinate space is indicative of a medial/lateral position, and the second axis of the cylindrical coordinate space is indicative of an angle of rotation in a sagittal plane.
8 . The method of claim 1 , wherein mapping the projected geometry to each of the plurality of poses in the range of motion using the position data comprises mapping coordinates of the first geometry to a linear position on the first axis, an angular position on the second axis, and a radial distance from the second bone.
9 . The method of claim 8 , wherein selecting the intersecting geometry comprises selecting, for each combination of linear position on the first axis and angular position on the second axis, a smallest radial distance from the second bone of the mapped, projected geometry.
10 . The method of claim 1 , further comprising filtering, by the computing device, the first geometry data to remove geometry that does not interface with the second bone-contacting surface of the second bone.
11 . The method of claim 10 , wherein filtering the first geometry data comprises removing geometry data outside of predetermined bounds.
12 . The method of claim 10 , wherein filtering the first geometry data comprises removing geometry data having a slope above a predetermined threshold.
13 . The method of claim 10 , wherein filtering the first geometry data comprises removing geometry data that faces away from the second bone-contacting surface, wherein geometry data that faces away from the second bone-contacting surface has an angle that is above a predetermined threshold relative to an imaginary high point in the direction of the second bone-contacting surface.
14 . The method of claim 1 , further comprising filtering, by the computing device, the second geometry data, wherein filtering the second geometry data comprises at least one of removing geometry data that comprises outlier geometry or removing geometry data that is isolated from other geometry data of the second geometry data.
15 . The method of claim 1 , wherein the first bone is a tibia, the second bone is a femur, the bone-contacting surface is a tibial plateau, and the second bone-contacting surface is a femoral condyle.