|Abstract: ||During the last decade, an increasing number of advanced platforms for
robotic assisted Minimally Invasive Surgery (MIS) have been translated
from research concepts to practical systems used in routine clinical settings.
Such systems have defined their own niche in the market place and
are gaining increasing acceptance by the surgical community. More importantly,
they improve surgeons' dexterity and intra-operative visualisation
together with the benefits of improved procedural time, safety, consistency
and patient outcome.
Some of the new technical features integrated within current robotic systems
include higher degrees of freedom for more agile manoeuvring, tremor
filtering and haptic feedback. Where the next frontier lies in terms of novel
means of surgical assistance is in navigation systems that would enable
intra-operative surgical guidance, imposing dynamic active constraints and
high fidelity augmented reality environments.
At the foundation of all navigation systems lies an accurate 3D reconstruction
algorithm. To overcome the current limitations of feature-based
matching and reconstruction systems, this thesis investigates a method to
integrate depth information from conventional stereo 3D reconstruction with
photometric cues from Shape-from-Shading techniques. This is further enhanced
with a gaze-contingent framework suitable for intra-operative navigation
during MIS. The resulting system is suitable for applications with
existing MIS platforms without the need of additional hardware, ensuring
increased accuracy in areas without salient anatomical landmarks or artificially introduced fiducials.
Furthermore, a multi-scale feature detector is proposed for intra-operative
stereo telestration required for telementoring and remote collaboration of
robotic assisted MIS. An improved formulation of the current state-of-the-art
in Shape-from-Shading is integrated with intra-operative scenes for accurate
metric depth recovery. The potential clinical application of the technique is demonstrated for autonomous navigation of wireless capsule endoscopes.
Future research directions and preliminary results of integrating photometric
stereo constraints for reliable reconstruction of featureless, non-
Lambertian deforming tissue surfaces are provided and all methods proposed
have been validated with either in vivo or phantom experiments to
justify their potential clinical values in MIS.|