System and method to register anatomy without a probe
Systems and methods provide registration of anatomical points of interest to a surgical navigation system using a camera only without a separate tracked probe. Graphical elements are overlaid on real time images of patient anatomy. Workflow directs the capture of image registration data (pose data) when the graphical elements are aligned. The graphical elements may represent positional features of the camera such as one or more axis positions.
1. A method to establish an anatomical reference point in a 3D space for images as defined by a surgical navigation system having a processing device coupled to a camera, the method comprising:
receiving, at the processing device, images of an anatomy of a patient including a tracker where the tracker is in a fixed position relative to the anatomy thereby to define a position of the anatomy in the 3D space;
displaying, by the processing device, a targeting marker, in real time, overlaid on a display of the images from the camera, the targeting marker indicating a position of a light ray in the images;
defining, by the processing device, a first 3D vector relative to the 3D space for the light ray in response to input received indicating the light ray is aligned with an anatomical reference point relative to the anatomy;
after defining the first 3D vector: displaying, by the processing device, a first light ray indicator showing the light ray defined according to the first 3D vector, in real time, overlaid on the display of the images from the camera;
defining, by the processing device, a second 3D vector of the light ray in response to input received indicating the light ray is aligned with the anatomical reference point and where the second 3D vector is different from the first 3D vector;
stopping, by the processing device, the displaying of the first light ray indicator following defining the second 3D vector; and
calculating, by the processing device, a position in the 3D space of the anatomical reference point using the first 3D vector and the second 3D vector.
2. The method of claim 1 comprising displaying, by the processing device, a reference point indicator for the anatomical reference point at the position, in real time, overlaid on the display of the images from the camera.
3. The method of claim 1 , wherein the camera is in a first position when input is received to define the first 3D vector and the camera is in a second position when input is received to define the second 3D vector thereby to provide the second 3D vector that is different from the first 3D vector.
4. The method of claim 1 comprising providing workflow comprising instructions in a graphical user interface for a user to provide input to define the first 3D vector and the second 3D vector.
5. The method of claim 1 wherein the anatomy is a femur and the anatomical reference point is a knee center.
6. The method of claim 5 , wherein the tracker is in a position on the femur, proximate to the knee center, to be visible in a field of view of the camera.
7. The method of claim 5 comprising calculating, by the processing device, an axis of the femur 3D vector using the anatomical reference point and a hip center of rotation to define the axis of the femur.
8. The method of claim 7 comprising displaying, by the processing device, a femoral axis indicator showing the axis of the femur defined according to the axis of the femur 3D vector, in real time, overlaid on the display of the images from the camera.
9. The method of claim 1 comprising, prior to receiving the input for defining the second 3D vector:
defining, by the processing device, a candidate 3D vector for the light ray from images received after defining the first 3D vector; and
calculating a candidate position of the anatomical reference point using the first 3D vector and the candidate 3D vector; and
displaying, by the processing device, a candidate reference point indicator for the anatomical reference point at the candidate position, in real time, overlaid on the display of the images from the camera.