Surgical navigation system with flat panel registration fixture

A method of registering a medical image to a three-dimensional tracking space, the method comprising:

• obtaining an image generated by an x-ray medical imaging device,
• identifying in the image a first set of radiopaque markers based on recognizing the first set of radiopaque markers are arranged along at least four radial lines which extend from a center location, based on recognizing the radial lines are angularly spaced apart about the center location, and based on recognizing at least three of the radiopaque markers are arranged along each of the radial lines,
• identifying in the image locations of a second set of radiopaque markers based on recognizing the second set of radiopaque markers are arranged along a circle, wherein the first set of radiopaque markers are on an orientation plate, the second set of radiopaque markers are on a registration plate spaced apart from the orientation plate, and the orientation plate and the registration plate are attached to a base frame of a fixture mounted to the x-ray medical image device, and
• registering the image to a three-dimensional tracking space based on comparison of locations of the first set radiopaque markers in the image to locations of the second set radiopaque markers in the image.