1,720,976 research outputs found
Novel 3-DOF Simulated Annealing-Based Haptic Rendering Algorithm
No full textHaptic rendering requires high sampling rates and a quasi-instantaneous, ultra-low latency, response. Existing algorithms for collision detection are sequential in nature and are difficult to parallelize. A novel 3-DOF haptic rendering algorithm has been developed based on the simulated annealing algorithm. The simulated annealing algorithm is applied to find the collision between the haptic interface point and the virtual object. When there is no collision, the shortest distance between the haptic interface point and the virtual object will be returned. To test the haptic rendering algorithm basic geometric shapes have been used to confirm the feasibility of the developed algorithm. When choosing suitable object-dependent values for the simulated annealing parameters it becomes clear that the average update frequency reaches well above the desired update frequency of at least 1 kHz, including both the collision detection as well as the constraint-based force response, while obtaining high-fidelity force feedback. Finally, the simulated annealing algorithm lends itself perfectly for the development of dedicated hardware implementations to achieve massive parallel execution for different parts of the simulated annealing algorithm, which further increases the update frequency. Due to this increase in update frequency it will be possible to run the simulated annealing algorithm multiple times within one haptic loop (i.e. 1 kHz) and find multiple contact points simultaneously
Novel 3-DOF Simulated Annealing-Based Haptic Rendering Algorithm
No full textHaptic rendering requires high sampling rates and a quasi-instantaneous, ultra-low latency, response. Existing algorithms for collision detection are sequential in nature and are difficult to parallelize. A novel 3-DOF haptic rendering algorithm has been developed based on the simulated annealing algorithm. The simulated annealing algorithm is applied to find the collision between the haptic interface point and the virtual object. When there is no collision, the shortest distance between the haptic interface point and the virtual object will be returned. To test the haptic rendering algorithm basic geometric shapes have been used to confirm the feasibility of the developed algorithm. When choosing suitable object-dependent values for the simulated annealing parameters it becomes clear that the average update frequency reaches well above the desired update frequency of at least 1 kHz, including both the collision detection as well as the constraint-based force response, while obtaining high-fidelity force feedback. Finally, the simulated annealing algorithm lends itself perfectly for the development of dedicated hardware implementations to achieve massive parallel execution for different parts of the simulated annealing algorithm, which further increases the update frequency. Due to this increase in update frequency it will be possible to run the simulated annealing algorithm multiple times within one haptic loop (i.e. 1 kHz) and find multiple contact points simultaneously
Cloud-based Collaboration Platform for Orthognatic Surgical Planning
No full textMany medical departments use several multi-disciplinary technologies to support the planning of the surgery. For complex operations a collaboration between different experts can improve
the success rate, but the tools are mostly on-premises software and limit the good cooperation. In this case, the orthognathic and dental surgery uses 3D and CT scans to plan the surgery beforehand by making use of 3D image processing, visualization and planning tools. We researched the possibility to create an online cloud-based platform to run the currently used surgical planning tools to improve the collaboration between several experts. We achieved multiple two-factor authentication user logins for security, simultaneous surgical planning sessions for collaboration and lightweight multi-platform support for existing technologies
Cloud-based Collaboration Platform for Orthognatic Surgical Planning
No full textMany medical departments use several multi-disciplinary technologies to support the planning of the surgery. For complex operations a collaboration between different experts can improve
the success rate, but the tools are mostly on-premises software and limit the good cooperation. In this case, the orthognathic and dental surgery uses 3D and CT scans to plan the surgery beforehand by making use of 3D image processing, visualization and planning tools. We researched the possibility to create an online cloud-based platform to run the currently used surgical planning tools to improve the collaboration between several experts. We achieved multiple two-factor authentication user logins for security, simultaneous surgical planning sessions for collaboration and lightweight multi-platform support for existing technologies
Real-time SVM-based emotion recognition algorithm
No full textThe rise in ageing population is a global trend and this increasing number of elderly requires the development of new techniques, especially in the healthcare. Nowadays, already a lot of research is conducted with respect to the development of healthcare robots. However, these robots often focus on practical tasks and lack on a social interaction level. To enhance these social skills it is necessary to analyze both verbal and non-verbal communication. This paper focuses on the latter form of communication, more specific on emotion detection. To accomplish this the developed algorithm extracts specific facial cues, in the form of displacement ratios, and interprets these cues with a cascade of SVMs. In total there are 4 different steps to achieve the emotion detection. First, the countenance is detected with an adapted Histogram of Oriented Gradients (HoG) algorithm. Subsequently, 19 feature points are derived from the facial region. The next step comprises the calculation of 12 displacement ratios based on the distance between those feature points in successive frames. Finally, the displacement
ratios are used as feature vectors for a multi-class SVM in cascade
with a binary SVM. The developed algorithm is evaluated on the Extended Cohn-Kanade (CK+) dataset and has an overall accuracy of 89.78% with a detection speed of less than 30ms, which makes it suitable for real-time applications.FW
Cloud-based orthognathic surgical planning platform
No full textMulti-disciplinary technologies are currently involved in orthognathic and dental surgery. By using 3D and CT scans, the surgery can be planned beforehand by making use of 3D image processing, visualization and planning tools. With 3D printing, accurate splints and wafers can be generated for the surgery. Nowadays, these tools are on-premises software and this makes it very hard for collaboration between several specialists. Therefore, we researched the possibility to create an online cloud-based platform to run the currently used surgical planning tools. We achieved multiple two-factor authentication user logins, simultaneous surgical planning sessions and lightweight multi-platform support.The research in this paper was partly funded by the bilateral FWOMOST (Belgian Research Council research cooperation contract
G.0524.13
Haptic Collision Detection on Highly Complex Medical Data Structures
No full textNowadays, the planning procedure for orthognathic surgery consists of a manual workflow which relies on cost and time consuming tasks. The burden that this procedure has on the surgeon and the medical staff can be reduced by substituting
the current procedure with a digital workflow. In the novel
workflow the surgeon uses a haptic feedback device to mimic
the haptic information perceived from the manual procedure.
However, highly complex 3D medical scan models of the upper
and lower jaw are needed to reproduce a realistic feeling. These
complex models stress the need for an efficient collision detection algorithm to obtain the necessary update rate of at least 1 kHz for haptic feedback devices. In this paper the potential of the Inner Sphere Tree (IST) data structure is analyzed for application in the orthognathic surgery digital planning workflow. An open-source C++ program is developed on the CHAI3D platform for the implementation and evaluation of the IST. For the evaluation, the detection speed, but also the accuracy of the collision detection, in terms of the error introduced by the proximity of the minimum
distance between bounding volume hierarchies (BVHs), are taken
into consideration. Various tree traversal algorithms, distance
and backtracking, are implemented and evaluated. Finally, a
multi-point tree traversal algorithm is developed to find multiple contact-points between two ISTs. Due to the added optimizations and by using these tree traversal algorithms, the required update speed is reached.FW
Analysis of collision detection using Implicit Sphere Tree in haptic interaction environments for maxillofacial surgery applications
No full textFacial malformations such as overbite or underbite
can be treated by maxillofacial surgery where the mandibula (i.e.
the lower jaw) and/or maxilla (i.e. the upper jaw) is repositioned
to obtain a preferential occlusion. These treatments need to be
carefully planned prior to the actual operation. The planning of
such surgery is an intensive and time consuming procedure in
which the experience and knowledge of the surgeon plays a major
role. As part of a CAD-based surgery planning, haptic interaction
using 3D virtual models of the mandibula and maxilla, haptic
feedback can make planning and surgery much more efficient.
Haptic devices bridge the gap between the virtual environment
and the physical world. An important step in such haptics based
workflow is the collision detection between the two models at an
update frequency of at least 1000 Hz. In this paper the possibility
of the Implicit Sphere Tree algorithm as a collision detection
algorithm tailored for this specific application is presented
A review on the applications of virtual reality, augmented reality and mixed reality in surgical simulation: an extension to different kinds of surgery
No full textBackground: Research proves that the apprenticeship model, which is the gold standard for training surgical residents, is obsolete. For that reason, there is a continuing effort toward the development of high-fidelity surgical simulators to replace the apprenticeship model. Applying Virtual Reality Augmented Reality (AR) and Mixed Reality (MR) in surgical simulators increases the fidelity, level of immersion and overall experience of these simulators. Areas covered: The objective of this review is to provide a comprehensive overview of the application of VR, AR and MR for distinct surgical disciplines, including maxillofacial surgery and neurosurgery. The current developments in these areas, as well as potential future directions, are discussed. Expert opinion: The key components for incorporating VR into surgical simulators are visual and haptic rendering. These components ensure that the user is completely immersed in the virtual environment and can interact in the same way as in the physical world. The key components for the application of AR and MR into surgical simulators include the tracking system as well as the visual rendering. The advantages of these surgical simulators are the ability to perform user evaluations and increase the training frequency of surgical residents
Haptic Collision Detection on Highly Complex Medical Data Structures
No full textNowadays, the planning procedure for orthognathic surgery consists of a manual workflow which relies on cost and time consuming tasks. The burden that this procedure has on the surgeon and the medical staff can be reduced by substituting
the current procedure with a digital workflow. In the novel
workflow the surgeon uses a haptic feedback device to mimic
the haptic information perceived from the manual procedure.
However, highly complex 3D medical scan models of the upper
and lower jaw are needed to reproduce a realistic feeling. These
complex models stress the need for an efficient collision detection algorithm to obtain the necessary update rate of at least 1 kHz for haptic feedback devices. In this paper the potential of the Inner Sphere Tree (IST) data structure is analyzed for application in the orthognathic surgery digital planning workflow. An open-source C++ program is developed on the CHAI3D platform for the implementation and evaluation of the IST. For the evaluation, the detection speed, but also the accuracy of the collision detection, in terms of the error introduced by the proximity of the minimum
distance between bounding volume hierarchies (BVHs), are taken
into consideration. Various tree traversal algorithms, distance
and backtracking, are implemented and evaluated. Finally, a
multi-point tree traversal algorithm is developed to find multiple contact-points between two ISTs. Due to the added optimizations and by using these tree traversal algorithms, the required update speed is reached.FW
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