Method and navigation system for registering two-dimensional image data set with three-dimensional image data set of body of interest

A navigation system for registering a two-dimensional image data set of a body of interest with a three-dimensional image data set of the body of interest, comprising:

• a memory, configured to store a plurality of commands;
• and
• a processor, configured to obtain the plurality of commands from the memory to perform following steps:
• generating a first reconstructed image from the three-dimensional image data set with a first spatial parameter of a virtual camera;
• calculating a reference similarity value according to the first reconstructed image and the two-dimensional image data set of the virtual camera that is moved from the first spatial parameter to a second spatial parameter;
• generating a second reconstructed image from the three-dimensional image data set with the second spatial parameter;
• calculating a comparison similarity value according to the second reconstructed image and the two-dimensional image data set;
• comparing the comparison similarity value with the reference similarity value;
• and
• registering the two-dimensional image data set to the three-dimensional image data set if the comparison similarity value is not greater than the reference similarity value to indicate that the three-dimensional image data set is aligned with the two-dimensional image data set, wherein the two-dimensional image data set and the three-dimensional image data set are used in a computer-assisted surgical navigation after registering, wherein if the three-dimensional image data set cannot align with the two-dimensional image data set, the processor is configured to obtain the plurality of commands from the memory to perform following steps:
• defining a first vector of a registered virtual camera in a coordinate system of the three-dimensional image data set;
• obtaining a first transformed vector of the virtual camera in the coordinate system of the three-dimensional image data set by transforming the first vector of the registered virtual camera through at least one transforming matrix;
• defining a focal point of the virtual camera at a reference point of the two-dimensional image data set in the coordinate system of the three-dimensional image data set;
• and
• repositioning the virtual camera according to the first transformed vector and the focal point of the virtual camera.