To diet or not if you have inflammatory bowel disease

Liver surgery remains a difficult challenge in which preoperative data analysis and strategy definition may play a significant role in the success of the procedure. Medical image processing led to a major improvement of patient care by guiding the surgical gesture. From this initial data, new technologies of virtual reality and augmented reality can increase the potential of such images. The 3D modeling of the liver of patients from their CT scan or MRI thus allows an improved surgical planning. Simulation allows the procedure to be simulated preoperatively and offers the opportunity to train the surgical gesture before carrying it out. These three preoperative steps can be used intraoperatively thanks to the development of augmented reality, which consists of superimposing the preoperative 3D modeling of the patient onto the real intraoperative view of the patient and his/her organs. Augmented reality provides surgeons with a transparent view of the patient. This facilitated the intraoperative identification of the vascular anatomy and the control of the segmental arteries and veins in liver surgery, thus preventing intraoperative bleeding. It can also offer guidance due to the virtual improvement of their real surgical tools, which are tracked in real-time during the procedure. During the surgical procedure, augmented reality, therefore, offers surgeons a transparent view of their patient, which will lead to the automation of the most complex maneuvers. The new ways of processing and analyzing liver images have dramatically changed the approach to liver surgery.     

From virtual reality to web-based multimedia maintenance manuals

This paper focuses on a structured methodology that uses virtual reality (VR) and digital human modeling (DHM) to study maintenance procedures of industrial products. VR technologies help to highlight the most critical aspects of maintenance operations, while DHM tools allow detailing working sequences. Data coming from these analyses are then used to draw up a multimedia maintenance manual based on digital video animations, audio comments, explanatory images and written recommendations. Information is available to maintenance personnel directly on the working site through portable electronic devices. Further, web-based multimedia manuals can be updated on-line and help to shorten learning time and maintenance downtimes.     

A practical guide to cardiovascular 3D printing in clinical practice: Overview and examples

The advent of more advanced 3D image processing, reconstruction, and a variety of three‐dimensional (3D) printing technologies using different materials has made rapid and fairly affordable anatomically accurate models much more achievable. These models show great promise in facilitating procedural and surgical planning for complex congenital and structural heart disease. Refinements in 3D printing technology lend itself to advanced applications in the fields of bio‐printing, hemodynamic modeling, and implantable devices. As a novel technology with a large variability in software, processing tools and printing techniques, there is not a standardized method by which a clinician can go from an imaging data‐set to a complete model. Furthermore, anatomy of interest and how the model is used can determine the most appropriate technology. In this over‐view we discuss, from the standpoint of a clinical professional, image acquisition, processing, and segmentation by which a printable file is created. We then review the various printing technologies, advantages and disadvantages when printing the completed model file, and describe clinical scenarios where 3D printing can be utilized to address therapeutic challenges.

     

Framework for verification of positional tolerances with a 3D non-contact measurement method

New methods of data acquisition such as 3D scanners have become increasingly necessary for the verification of the geometric dimensioning and tolerancing (GD&T) specifications in the manufacture of industrial parts. This paper proposes a method for the verification of a positional tolerance in two cylindrical features in an industrial part digitized using a 3D non-contact scanner. Apart from enabling an adequate quantification of the obtained results, this method also permits the displaying of different ways of visualizing the results. The tolerance zone within which the used scanner carries out the analysis was measured and quantified. Some aspects taken into consideration were the geometric quality of the piece and the repeatability, the reproducibility and the uncertainty of the digital process, which comprises the acquisition and processing of the data. This research work concludes that the digital method presented hereby, with its corresponding virtual inspection, is valid for the verification of positional tolerances, even when it is required to maintain the GD&T specification regardless of the feature size. In addition, this article raises the discussion over the best way to compute the traditional datum referencing rules to the new data acquisition methods.     

User-centered design of a virtual reality exhibit for archaeological museums

Nowadays, the adoption of virtual reality (VR) exhibits is increasingly common both in large and small museums because of their capability to enhance the communication of the cultural contents and to provide an engaging and fun experience to its visitors. The paper describes a user-centered design (UCD) approach for the development of a VR exhibit for the interactive exploitation of archaeological artefacts. In particular, this approach has been carried out for the development of a virtual exhibit hosted at the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The main goal was to enrich the museum with a playful and educational VR exhibit able to make the visitors enjoy an immersive and attractive experience, allowing them to observe 3D archaeological artefacts in their original context of finding. The paper deals with several technical issues commonly related to the design of virtual museum exhibits that rely on off-the-shelf technologies. The proposed solutions, based on an UCD approach, can be efficiently adopted as guidelines for the development of similar VR exhibits, especially when very low budget and little free space are unavoidable design requirements.     

Requirements for an enactive tool to support skilled designers in aesthetic surfaces definition

In common industrial practice the definition of shapes of styling products is performed by product designers by handcrafting scale models made of clay while exploiting their manual skills. Several Computer-Aided Styling tools have been introduced in years with the aim of allowing the creation of product shapes in digital. But the low interest of developers to provide designers with a natural interface that would allow them to continue to use their learned manual skills, has led them to continue to work on clay materials and produce expensive physical prototypes. Enactive Interfaces have been demonstrated to be effective to support the exploitation of human skills including the manual skill of industrial designers. The paper describes an Enactive Interface that has been conceived to support designers in the evaluation of aesthetic shapes, which consists of a combination of an active manual and visual exploration of the shape. The Enactive Interface is the combination of visuo-haptic technologies and has been implemented on the basis of observations of the shape evaluation activity performed by manually skilled designers. In the paper we describe the testing sessions performed to capture the designers’ manual skill, the working principles of the enactive interface and finally the results of the subsequent testing activities specifically carried out to evaluate the effectiveness of the interface.     

Augmented reality technology for preoperative planning and intraoperative navigation during hepatobiliary surgery: A review of current methods

Background

Augmented reality (AR) technology is used to reconstruct three-dimensional (3D) images of hepatic and biliary structures from computed tomography and magnetic resonance imaging data, and to superimpose the virtual images onto a view of the surgical field. In liver surgery, these superimposed virtual images help the surgeon to visualize intrahepatic structures and therefore, to operate precisely and to improve clinical outcomes.

On methods to identify the symmetry line of human back

This paper analyse and compare the methods to detect and represent the human symmetry line. In the last years, the development of 3D scanners has allowed to replace the traditional techniques (marking based methods) with modern methodologies that, starting from a 3D valid discrete geometric model of the back, perform the posture and vertebral column detection based on a complex processing of the acquired data. The purpose of the paper is a critical discussion of the state of the art in order to highlight real potentialities and limitations of the most important methodologies proposed for human symmetry line detection.     

Recent advances in 3D computed tomography techniques for simulation and navigation in hepatobiliary pancreatic surgery

A few years ago it could take several hours to complete a 3D image using a 3D workstation. Thanks to advances in computer science, obtaining results of interest now requires only a few minutes. Many recent 3D workstations or multimedia computers are equipped with onboard 3D virtual patient modeling software, which enables patient‐specific preoperative assessment and virtual planning, navigation, and tool positioning. Although medical 3D imaging can now be conducted using various modalities, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasonography (US) among others, the highest quality images are obtained using CT data, and CT images are now the most commonly used source of data for 3D simulation and navigation image. If the 2D source image is bad, no amount of 3D image manipulation in software will provide a quality 3D image. In this exhibition, the recent advances in CT imaging technique and 3D visualization of the hepatobiliary and pancreatic abnormalities are featured, including scan and image reconstruction technique, contrast‐enhanced techniques, new application of advanced CT scan techniques, and new virtual reality simulation and navigation imaging.     

Appearance preserving simplification of 3D CAD model with large-scale assembly structures

Currently commercial 3D CAD systems which had only been used in upper stage of design scenes become widely used in lower stages such as rough sales purposes, model exporting to external users or e-commerce on Web. Usually, in the design stage, solid models even of very fine parts or full-detailed shapes have been built in the CAD systems, and the assembly models tend to have a huge number of parts and very complex inner structures. Moreover, for achieving the light-weight and strengthened parts, the inner structures of the housing such as ribs or bosses have had very complex geometries. However, when they are used for browsing, styling review and sales purposes, there is hardly the occasion where is full-detailed assembly models are required, and the primary purpose of the systems is often to fast render external shapes rather than to render detailed inner structures. Appearance preserving simplification of large scale assembly model available to the commercial 3D CAD systems is strongly needed for these purposes. Therefore, this paper proposes several appearance preserving simplification methods of 3D CAD model with large-scale assembly structures. Three simplification methods are proposed in the paper; (1) only by removing invisible parts from the assembly, (2) by removing both invisible form features from the part surface and invisible parts themselves from the assembly, and (3) by removing both form features and parts which are invisible even when position and orientation of movable parts change in the assembly. Our methods are based on an algorithm which can directly detect invisible parts or features by pre-rendering the models from multiple view directions and reading the rendered results from the frame buffer. Our algorithm can be carried out regardless of CAD systems. Thanks to using the current GPU, invisible parts or features detection is robust and fast in the algorithm. If needed, geometric dependency among the features in the assembly can be kept even in the simplification. The performances of these simplification methods in model size reduction and the processing time are examined.     

Interactive design of dental implant placements through CAD-CAM technologies: from 3D imaging to additive manufacturing

In the field of oral rehabilitation, the combined use of 3D imaging technologies and computer-guided approaches allows the development of reliable tools to be used in preoperative assessment of implant placement. In particular, the accurate transfer of the virtual planning into the operative field through surgical guides represents the main challenge of modern dental implantology. Guided implant positioning allows surgical and prosthetic approaches with minimal trauma by reducing treatment time and decreasing patient’s discomfort. This paper aims at defining a CAD/CAM framework for the accurate planning of flapless dental implant surgery. The system embraces three major applications: (1) freeform modelling, including 3D tissue reconstruction and 2D/3D anatomy visualization, (2) computer-aided surgical planning and customised template modelling, (3) additive manufacturing of guided surgery template. The tissue modelling approach is based on the integration of two maxillofacial imaging techniques: tomographic scanning and surface optical scanning. A 3D virtual maxillofacial model is created by matching radiographic data, captured by a CBCT scanner, and surface anatomical data, acquired by a structured light scanner. The pre-surgical planning process is carried out and controlled within the CAD application by referring to the integrated anatomical model. A surgical guide is then created by solid modelling and manufactured by additive techniques. Two different clinical cases have been approached by inserting 11 different implants. CAD-based planned fixture placements have been transferred into the clinical field by customised surgical guides, made of a biocompatible resin and equipped with drilling sleeves.     

3D modelling and knowledge: tools to automate prosthesis development process

Computer-aided tools can help to realize custom-fit products characterized by a strict interaction with human body and definitely improve quality of life, in particular of people with disabilities. The paper refers to this context and to a specific custom-fit product, the lower limb prosthesis. It presents an innovative framework centred on virtual models of the patient’s body, to design and configure lower limb prosthesis, both transfemoral and transtibial. The framework integrates virtual prototyping and knowledge-based tools to support the orthopaedic technician during all the steps of the lower limb prosthesis design, suggesting rules and procedures for each task. First, the considered product is introduced, and then, the new design framework is described as well as main steps and related tools, from socket modelling to standards component selection and final prosthesis assembly. Results of preliminary experimentation and final remarks conclude the paper.     

Recognition of intrinsic quality properties for automatic geometric inspection

In the last few years the need for methodologies capable of performing an automated geometric inspection has increased. These methodologies often use 3D high-resolution optical digitisers to acquire points from the surface of the object to be inspected. It is expected that, in the near future, geometric inspection will be requiring more and more the use of these instruments. At present geometric inspection is not profiting from all the opportunities attainable by 3D high-resolution optical scanners or from the numerous tools which can be used for processing the point cloud acquired from the inspected product. For some years now, these authors have been working on a new methodology for automatic tolerance inspection working from a 3D model acquired by optical digitisers. In this paper all the information recognisable in a scanned object is organised into a new data structure, called Recognised Geometric Model (RGM). The final aim is to define a representation of the inspected object for the automatic evaluation of the non-idealities pertaining to the form, orientation and location of the non-ideal features of the acquired object. The key concept of the proposed approach is the capability to recognise some intrinsic nominal properties of the acquired model. These properties are assumed as references to evaluate the non-idealities of the inspected object. With this approach the references of geometric inspection are searched for in the inspected object independently of a tolerance specification and of the availability of a 3D nominal representation. The high-level geometric information within RGM depends on the rules used for its identification. The capability to recognise specific categories of nominal references offers the possibility of introducing new tolerances to be specified. The proposed approach has been implemented in original software by means of which a specific test case has been analysed.     

A comparative evaluation of human interaction for design and assembly of 3D CAD models in desktop and immersive environments

Computer aided design (CAD) systems have become today the basic tools used to design and develop products in the industry. In current CAD software most of the editing commands are issued with the aid of widgets and alphanumeric data input devices, while research community is proposing the use of virtual reality environments for CAD modelling. This paper presents an experimental study which compares the performance and usability of a multimodal immersive VR (virtual reality)-CAD system with a traditional CAD system. A comparative analysis was done for the modelling and the assembling process of 3D models. The results obtained from this investigation have shown that, in spite of the variety of interface devices in the virtual environment which provide a natural interaction to the user, the modelling time is about the same compared with a traditional desktop interface. The assembling time, however, is shown to be much smaller for multimodal system. Furthermore, the multimodal interface poses a higher physical stress factor, the hand movement distance being on average 1.6–2.3 times greater than the desktop interface for modelling process and assembling process, respectively. A post-experiment questionnaire shows that the multimodal system produce a great satisfaction for users in modelling and assembly processes.     

Preserving car stylists’ design intent through an ontology

This paper presents a first step in the elaboration of a knowledge-based modelling environment supporting the conceptual design phase of an industrial product; more precisely, car styling is the considered application field. To capture and structure the semantics embedded in the first sketches representing the product, an ontology has been created and will be the interface between the modeller and the stylist to generate and manipulate the curves forming the basic framework of the product shape at the early design phase. The ontology has been conceived in two layers: the first fragment captures the contextual semantic information specific to cars. Whereas the second fragment is product-independent and is related to the manipulation of curves based on a process grammar, providing an exhaustive and intuitive classification and manipulation of curves. The links between these two subsets will be able to map the aesthetic intent through shape characteristics and operators intuitive for designers.     

Brave New Worlds: How Virtual Environments Can Augment Traditional Care in the Management of Diabetes

New technologies, such as online networking tools, offer innovative ways to engage patients in their diabetes care. Second Life (SL) is one such virtual world that allows patients to interact in a 3D environment with peers and healthcare providers. This article presents a framework that demonstrates how applications within SL can be constructed to meet the needs of patients with diabetes, allowing them to attend group visits, learn more about lifestyle changes, and foster a sense of support and emotional well-being. This experiential approach to education may prove more engaging, and therefore successful, than existing strategies. Addressing concerns relating to privacy and liability is a necessary first step to engage providers in this new approach to patient care.     

Using high-level models for modeling industrial machines in a virtual environment

The work presented in this paper deals with a platform independent model formalism for designing virtual reality applications. In our approach, we focused on industrial machine simulators design. The structure of an industrial machine model is composed by “Virtual Components” which corresponds to the physical industrial components of the machine and a control part which corresponds to the functional specification of the machine. Each virtual component is modeled by VRML model for geometry and by hybrid automata (HA) for behavior. The control part is modeled by Sequential Function Charts (SFC), as it is the case in the majority of industrial machines. Those SFC are translated to HA and composed with the virtual components HA. The whole HA model of the machine is then implemented in the generic virtual environment “OpenMASK” by specific software translation tools which was developed previously. This method makes virtual prototyping accessible by the specialists in the domain of industrial machine design domain In this paper, we describe the high level modeling method putting the accent on the coupling between the control part and the process and then we apply it in the case of an assembly machine.     

Designing virtual environments for risk prevention: the MELISSA approach

Industrial safety management systems are composed of a set of formal and informal rules. These rules are subject to constant negotiations among industrial staff concerned by these rules. The negotiation process needs to take into account the safety rules and the relevant elements of their application contexts. We propose to use a virtual environment to stimulate this process. The success of such negotiations (in virtual environments) depends on the identification of required knowledge for representing safety rules application contexts. In this paper we present our model and methodology MELISSA that aim at identifying this knowledge, and to share it within the virtual environment design team. We first describe the knowledge needed to represent a working situation. Then, we present elements required for the conception of such virtual environments. Finally, we discuss the interest of our approach.