Francesca De Crescenzio

3D restitution, restoration and prototyping of a medieval damaged skull

Purpose – The purpose of this paper is to describe the method of virtually and physically reconstructing the missing part of a badly damaged medieval skull by means of reverse engineering, computer‐aided design (CAD) and rapid prototyping (RP) techniques.Design/methodology/approach – Laser scanning data were used to create the 3D model of the damaged skull. Starting from this digital model, a virtual reconstruction of the missing part of the skull, based on the ideal symmetry with respect to the mid‐sagittal plane, was achieved in a CAD environment. Finally, the custom‐designed model was directly fabricated by means of the RP process.Findings – The result shows that the designed missing part of the skull fits very well with the existing skeletal remains. The final physical assembly of the prototyped element on the damaged skull was tested, restoring it to its whole original shape.Research limitations/implications – The entire process was time‐consuming and may be applied just to the most representative sk...

Computer-aided design and manufacturing construction of a surgical template for craniofacial implant positioning to support a definitive nasal prosthesis.

AIM To design a surgical template to guide the insertion of craniofacial implants for nasal prosthesis retention. MATERIALS AND METHODS The planning of the implant position was obtained using software for virtual surgery; the positions were transferred to a free-form computer-aided design modeling software and used to design the surgical guides. A rapid prototyping system was used to 3D-print a three-part template: a helmet to support the others, a starting guide to mark the skin before flap elevation, and a surgical guide for bone drilling. An accuracy evaluation between the planned and the placed final position of each implant was carried out by measuring the inclination of the axis of the implant (angular deviation) and the position of the apex of the implant (deviation at apex). RESULTS The implant in the glabella differed in angulation by 7.78°, while the two implants in the premaxilla differed by 1.86 and 4.55°, respectively. The deviation values at the apex of the implants with respect to the planned position were 1.17 mm for the implant in the glabella and 2.81 and 3.39 mm, respectively, for those implanted in the maxilla. CONCLUSIONS The protocol presented in this article may represent a viable way to position craniofacial implants for supporting nasal prostheses.

Improving the spatial orientation of human teeth using a virtual 3D approach

Since teeth are resistant to decomposition processes, they provide important and at times unique sources of information about fossil humans. Fortunately, dental remains reflect significant evolutionary changes. These changes make a very important and often exclusive contribution to the definition of new taxa or the attribution of fossil specimens to existing taxa. The traditional approach to dental morphometric analyses usually focuses on the recording of several measures of the tooth with calipers, especially the two basic crown diameters (buccolingual and mesiodistal). However, since these measures do not adequately represent the complex morphology of the tooth, 2D images and 3D digital models of dental morphology have been used. For both types of analysis, the possibility of correctly comparing homologous teeth depends on the adoption of a common orientation system. The lack of such a system makes it difficult to compare the results of different studies. Here we describe a new method for orienting teeth specifically devised for the upper and lower first molar (M1). Samples of unworn maxillary (n=15) and mandibular (n=15) first molars of modern humans were scanned with a Roland Picza 3D digitizer. The 3D virtual models were used to compare our new orientation method with those proposed in the literature. The new orientation system, which meets a geometric criterion, is based on three points identified on the cervical line and ensures acceptable repeatability of the spatial positioning and orientation independent of the shape and wear of the first molar under investigation. This orientation system is a first step toward the creation of a virtual set of hominid and fossil human first molars, which will allow us to make comparisons via a sophisticated and noninvasive approach. This pilot study also provides guidelines to extend the new methodology to the other types of teeth.

New protocol for construction of eyeglasses-supported provisional nasal prosthesis using CAD/CAM techniques.

A new protocol for making an immediate provisional eyeglasses-supported nasal prosthesis is presented that uses laser scanning, computer-aided design/computer-aided manufacturing procedures, and rapid prototyping techniques, reducing time and costs while increasing the quality of the final product. With this protocol, the eyeglasses were digitized, and the relative position of the nasal prosthesis was planned and evaluated in a virtual environment without any try-in appointment. This innovative method saves time, reduces costs, and restores the patients aesthetic appearance after a disfiguration caused by ablation of the nasal pyramid better than conventional restoration methods. Moreover, the digital model of the designed nasal epithesis can be used to develop a definitive prosthesis anchored to osseointegrated craniofacial implants.

A first implementation of an advanced 3d interface to control and supervise uav (uninhabited aerial vehicles) missions

Recent analyses on the uninhabited aerial vehicle (UAV) accidents revealed that several kinds of human-system control problems occur in current UAV missions. Therefore, a design of the manmachine interface that allows for an efficient and effective interaction between the operator and the remote vehicle becomes one of the challenges in the development of more reliable UAVs. This paper presents a first implementation of an advanced interface for UAV ground control station based on a touch screen, a 3D virtual display, and an audio feedback message generator. The touch screen is used to send high level commands to the vehicle, the 3D virtual display provides a stereoscopic and augmented visualization of the complex scenario in which the vehicle operates, and the audio feedback message generator informs the operator about any change in operational scenario. The hardware/software architecture of the interface also includes a planning algorithm and a generic vehicle model. The interface has been tested by simulating several UAV missions. The results have shown that the interface requires an adequate level of workload to command the vehicle and allows the operator to build a good level of awareness of the state of the vehicle under his or her control, as well as of the environment in which it operates.

CAD/CAM bilateral ear prostheses construction for Treacher Collins syndrome patients using laser scanning and rapid prototyping

Ear defects in patients affected by Treacher Collins syndrome necessitate the replacement of the existing anatomic residuals of the ears with custom-made prostheses. This paper describes a multidisciplinary protocol involving both medicine and computer-aided design/computer-aided manufacturing for manufacturing ear prostheses. Using innovative prototyping technologies together with conventional silicone processing procedures, a step-by-step procedure is presented. The complete workflow includes laser scanning of the defective regions of a patients face, the use of 3D anatomic models from an ear digital library and rapid prototyping of both substructures for bar anchoring and moulds for silicone processing.

Three-Dimensional Obstacle Avoidance Strategies for Uninhabited Aerial Systems Mission Planning and Replanning

The ability to perform autonomous mission planning is considered one of the key enabling technologies for uninhabited aerial systems. Subsequently, a big effort is made in the development of algorithms capable of computing safe and efficient routes in terms of distance, time, and fuel. In this paper an innovative 3-D planning algorithm is presented. The algorithm is based on considering the uninhabited aerial systems representation of real world systems as objects moving in a virtual environment (terrain, obstacles, and no fly zones), which replicates the airspace. Original obstacle avoidance strategies have been conceived to generate mission plans that are consistent with flight rules and with the vehicle performance constraints. Simulation test results show that efficient routes are computed in a few seconds.

Advanced interface for UAV (Unmanned Aerial Vehicle) Ground Control Station

(Abstract) The research presented in this paper focuses on an advanced interface in a UAV Ground Control Station whose aim is to guarantee a high level of situation awareness and a low level of workload in the control and supervision of unmanned vehicles. The interface is based on a touch screen—used to command the UAV by means of high level commands—and a 3D Virtual Display which provides a stereoscopic and augmented visualization of the complex scenario in which the vehicle operates. Good levels of situation awareness are also guaranteed by an audio feedback that informs the operator about any change in operational situation, as well as when the mission objectives have been accomplished. Test results have revealed that this interface provides the operator with good sense of presence and enhanced awareness of the mission scenario and the aircraft under his control. 4-6 . For that reason, the design process must consider the human factors associated with UAV. Specifically, human factors such as attention, perception and cognition in managing the vehicle - in its normal operating state or in abnormal situations - must be considered. High levels of situation awareness would allow the operator to become aware of the relevant elements in the operational space and their relationships, and behave proactively in order to optimize UAV system performances and take actions to forestall possible future problems 1, , 2 3 . New interfaces should also require a low level of operator workload. The aim is to allow the operators to manage the mission easily, controlling even more complex situations. Recent papers present interfaces designed to satisfy such requirements 4-8 and allow the operator to deal with different degrees of vehicle autonomy. In each paper the architecture of the interface, tests and results are described. The interface detailed in ref. 4 comprises three display formats and supports a mouse and keyboard as input device. A Situation Awareness format provides the operator with a dynamic, large-scale presentation of the mission area. A UAV status format provides information about health and status of the vehicle. Finally, a multifunction format is used to manage most of the mission events. In order to test such interface, preplanned mission are simulated and managed by tester operators. They have to monitor the progress of the vehicle flight and adjust the path if unplanned events occur. Different levels of system automation and the time required to accomplish a task are the experimental variables. The results reveal that the testers maintain a good level of situation awareness and that they prefer a level of automation that allows them to select one solution among several produced by the system when path adjustments are needed. Ref. 6, 7, 8 describe an interface and present test results. Such an interface combines virtual representation, 2D visualization of operational space and flight parameters, and also supports different input devices, such as joystick, motion tracker and voice recognition. In this case the tester operator has to supervise the acquisition of imageries and the designation of target objectives while watching out for the pop-up warning signal (i.e. appearance of other vehicles and changes in a mission mode indicator). The time and placement of the pop-up is planned by an experiment designer before the experiments start. Again two levels of automation, called management by consent and management by exception, are considered. The results show that the virtual display

Augmented Reality in the Control Tower: A Rendering Pipeline for Multiple Head-Tracked Head-up Displays

The purpose of the air traffic management system is to accomplish the safe and efficient flow of air traffic. However, the primary goals of safety and efficiency are to some extent conflicting. In fact, to deliver a greater level of safety, separation between aircrafts would have to be greater than it currently is, but this would negatively impact the efficiency. In an attempt to avoid the trade-off between these goals, the long-range vision for the Single European Sky includes objectives for operating as safely and efficiently in Visual Meteorological Conditions as in Instrument Meteorological Conditions. In this respect, a wide set of virtual/augmented reality tools has been developed and effectively used in both civil and military aviation for piloting and training purposes (e.g., Head-Up Displays, Enhanced Vision Systems, Synthetic Vision Systems, Combined Vision Systems, etc.). These concepts could be transferred to air traffic control with a relatively low effort and substantial benefits for controllers’ situation awareness. Therefore, this study focuses on the see-through, head-tracked, head-up display that may help controllers dealing with zero/low visibility conditions and increased traffic density at the airport. However, there are several open issues associated with the use of this technology. One is the difficulty of obtaining a constant overlap between the scene-linked symbols and the background view based on the user’s viewpoint, which is known as ‘registration’. Another one is the presence of multiple, arbitrary oriented Head-Up Displays (HUDs) in the control tower, which further complicates the generation of the Augmented Reality (AR) content. In this paper, we propose a modified rendering pipeline for a HUD system that can be made out of several, arbitrary oriented, head-tracked, AR displays. Our algorithm is capable of generating a constant and coherent overplay between the AR layer and the outside view from the control tower. However a 3D model of the airport and the airport’s surroundings is needed, which must be populated with all the necessary AR overlays (both static and dynamic). We plan to use this concept as a basis for further research in the field of see-through HUDs for the control tower.

Design of Virtual Reality Based HMIs (Human Machine Interfaces) of Complex Systems

Aeronautical transport system is rapidly growing and more demanding. It has become a total system of complex systems in which the human is recognized as the decisional point that is asked to act quickly and safely. In this context, innovative technologies provide the challenge to design revolutionary Human Machine Interfaces for the people involved.In this paper a report of recent works in Human Machine Interfaces in aeronautics developed at the University of Bologna is presented. Synthetic visualization and task automation are the main commonalities in these projects. What we can expect from the future is then explored through an insight into technological aspects.