Surgical Navigation System Using Augmented Reality

  • The augmented reality (AR) based surgical navigation system allows virtual organs superimposed on the real organs. Particularly, internal organs and vessels that are covered in external organs are visualized, and this is  one of the attractive advantages of the AR system.  AR navigation system helps surgeons to recognize sensitive nerves, organs or vessels intuitively, and it is also helpful for minimum invasive surgery.

1. Registration techniques for Augmented reality

  • The registration techniques are most essential part in the AR navigation system. We are working on the three techniques which are camera calibration, hand-eye calibration and patient to image registration.
The AR system using external position tracker
The relation between camera and patient are obtained using optical position tracker.
Camera calibration & Hand-eye calibration
From the pattern images, intrinsic and extrinsic parameters of camera can be obtained and those are used for hand-eye calibration with singular value decomposition (SVD) method.  [Hand-eye means the relation between center of a CCD and coordination of passive marker attached on camera body]
Patient to image registration
Pair point registration (PPR) or iterative closest point (ICP) technique can be used for patient to image registration.

2. Improvement of depth perception in augmented reality

Seamless switching AR to VR
The position and orientation of virtual camera are controlled unrestrictedly in the VR environment and it is possible that observing the depth relation between virtual objects.
Cross sectional image plane for depth cues
The medical image plane is moved along the x, y and z axis and displayed on the screen perspectively
Minimum distance display
We developed additional visualization techniques to give an accurate depth information, that is displaying minimum distance between tool tip and surface of virtual organ.
– 최현석, 홍재성, “증강 현실을 이용한 수술내비게이션의 깊이감 표현 연구”, 제5차 대한의료로봇학회 학술대회, pp. 23-25, May 213
– Hyunseok Choi, Jaesung Hong, “Augmented reality navigation system for ear surgery“, Augmented Reality & Surgical Guidance workshop, The Hamlyn Symposium on Medical Robotics, Tuesday 25 June 2013