Improved visual SLAM for bronchoscope tracking and registration with pre-operative CT images

We present an improved patient-specific bronchoscopic navigation scheme by using visual SLAM for bronchoscope tracking. Bronchoscopic navigation system is used to assist physicians during the bronchoscopy examination. Conventional navigation system obtain the camera pose of bronchoscope based on image similarity of real bronchoscopic (RB) and virtual bronchoscopic (VB) images or the pose information from the additional sensor. We propose to use visual SLAM for bronchoscope tracking. The tracking procedure of visual SLAM is improved for processing bronchoscopic scene by considering the inter-frame displacement to filter 2D-3D matches used for pose optimization. The tracking result is registered to CT images to find the relationship between RB and CT the coordinate system. Virtual bronchoscopic views are generated corresponding to real bronchoscopic views by using the registration result and camera pose. Experimental results showed that our proposed method track more frames with higher accuracy on average than the the previous method. The virtual bronchoscopic views have high similarity with real bronchoscopic views.