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Gaze Contingent Robotic Control
The use of real-time binocular eye tracking for empowering the robots with human vision using knowledge acquired in situ, thus simplifying, as well as enhancing, robotic control in surgery. By utilizing the close relationship between the horizontal disparity and the depth perception, varying with the viewing distance, we demonstrate how vergence can be effectively used for recovering 3D depth at the fixation points and further be used for adaptive motion stabilization during surgery.
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Dense 3D Depth Recovery for Soft Tissue Deformation
The development of a practical strategy for dense 3D depth recovery and temporal motion tracking for deformable surfaces. The method combines image rectification with constrained disparity registration for reliable depth estimation.
The accuracy and practical value of the technique is validated with a tissue phantom with known 3D geometry and motion characteristics. It has been
shown that the performance of the proposed approach compares favorably against existing methods.
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Gaze Contingent Robotic Control
The use of real-time binocular eye tracking for empowering the robots with human vision using knowledge acquired in situ, thus simplifying, as well as enhancing, robotic control in surgery. By utilizing the close relationship between the horizontal disparity and the depth perception, varying with the viewing distance, we demonstrate how vergence can be effectively used for recovering 3D depth at the fixation points and further be used for adaptive motion stabilization during surgery.
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| Enhancement of Visual Realism with BRDF for Patient Specific Bronchoscopy Simulation
Photorealistic rendering of the bronchial lumen by directly deriving matched shading and texture parameters from video bronchoscope images. 2D/3D registration is used to match video bronchoscope images with 3D CT scan of the same patient, such that patient specific modelling and simulation with improved visual realism can be achieved. With the proposed method, shading parameters are recovered by modelling the bidirectional reflectance distribution function (BRDF) of the visible surfaces by exploiting the restricted lighting cofigurations imposed by the bronchoscope. The derived BRDF is then used to predict the expected shading intensity such that a texture map independent of lighting conditions can be extracted. This allows the generation of new views not captured in the original bronchoscopy video, thus allowing free navigation of the acquired 3D model with enhanced photo-realism. |
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Real-Time Photo-Realistic Rendering for Surgical Simulations with Graphics Hardware
A photo-realistic rendering approach based on real-time per-pixel effects by using the graphics hardware. Improved realism is achieved by a combined use of specular reflectance and refractance maps to model the effect of surface details and mucous layer on the overall visual appearance of the tissue. The key steps involved in the proposed technique are described, and quantitative performance assessment results demonstrate the practical advantages of the proposed technique. |
| pq-space Based 2D/3D Registration
A hybrid approach for 2D/3D registration in bronchoscope based on extracting surface normals from the video frames using linear shape from shading and surface normals specified from the 3D model. The method is not affected by the lighting of the 3D model and there is no need to adjust the illumination conditions in rendering. In addition, the method does not require feature extraction and matching, and has the potential to deal with local deformation because of the inherent surface information of the pq space. |
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Decoupling of Respiratory Motion with Wavelet and Principal Component Analysis
Motion decoupling technique for simplifying 2D/3D registration under the influence of normal respiratory motion. Wavelet analysis has been used to identify and remove episodes due to coughing and extreme breathing patterns. The method is particularly suitable for NDI Aurora catheter tip EM trackers.
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| Freehand Cocalibration of Optical and Electromagnetic Trackers for Navigated Bronchoscopy
A freehand method for calibrating electromagnetic position sensors by mapping the coordinate measurements to those from optical trackers. Unlike previous techniques, the proposed method allows for free movement of the calibration object, permitting second order continuity and interdependence between positional and angular corrections. The technique adopts radial basis function interpolation using a modified distance metric extended to handle orientation and direction spaces. The system provides efficient distortion correction of the EM field, and is applicable to clinical situations where a rapid calibration of EM tracking is required. |
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Virtual Bronchoscope
The construction of patient specific bronchoscope models for surgical skills assessment and simulations. Our strategy involves augmenting the traditional bronchial model derived from CT scans with in vivo bronchoscopy video.
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