The collaboration between humans and robots is one of the most disruptive and challenging research areas. Even considering advances in design and artificial intelligence, humans and robots could soon ally to perform together a number of different tasks. Robots could also became new playmates. In fact, an emerging trend is associated with the so-called phygital gaming, which builds upon the idea of merging the physical world with a virtual one in order to let physical and virtual entities, such as players, robots, animated characters and other game objects interact seamlessly as if they were all part of the same reality. This paper specifically focuses on mixed reality gaming environments that can be created by using floor projection, and tackles the issue of enabling accurate and robust tracking of off-the-shelf robots endowed with limited sensing capabilities. The proposed solution is implemented by fusing visual tracking data gathered via a fixed camera in a smart environment with odometry data obtained from robot's on-board sensors. The solution has been tested within a phygital gaming platform in a real usage scenario, by experimenting with a robotic game that exhibits many challenging situations which would be hard to manage using conventional tracking techniques.

The purpose of this study was to compare different students' backgrounds and two different didactic methodologies to profitably teach computer animation in Italian schools of design and engineering. Teachers and instructors have long been engaged in discussions to define effective curricula for teaching computer animation. Various multidisciplinary and collaborative methodologies have been proposed. This manuscript assesses both the impact of a collaborative teaching approach and the curriculum. Two equivalent learning paths are compared; both of them encompass courses of photography, storytelling and computer animation and require prerequisites in 3D modeling and rendering. The learning path of the \"Systemic Design\" degree is taught by the collaborative Open Space Technology (OST) approach, whereas the path of \"Cinema and Media Engineering\" is taught more conventionally (independent courses). The results clearly show how effective teaching methodologies cannot completely compensate for a nontechnical background; on the other hand, as expected, students appreciate and can take advantage of collaborative forms of teaching.

This paper presents a framework for automatically generating speech-based interfaces for controlling virtual and augmented reality (AR) applications on wearable devices. Starting from a set of natural language descriptions of application functionalities and a catalog of general-purpose icons, annotated with possible implied meanings, the framework creates both vocabulary and grammar for the speech recognizer, as well as a graphic interface for the target application, where icons are expected to be capable of evoking available commands. To minimize user's cognitive load during interaction, a semantics-based optimization mechanism was used to find the best mapping between icons and functionalities and to expand the set of valid commands. The framework was evaluated by using it with see-through glasses for AR-based maintenance and repair operations. A set of experimental tests were designed to objectively and subjectively assess first-time user experience of the automatically generated interface in relation to that of a fully personalized interface. Moreover, intuitiveness of the automatically generated interface was studied by analyzing the results obtained through trained users on the same interface. Objective measurements (in terms of false positives, false negatives, task completion rate, and average number of attempts for activating functionalities) and subjective measurements (about system response accuracy, likeability, cognitive demand, annoyance, habitability, and speed) reveal that the results obtained by the first-time users and experienced users with the proposed framework's interface are very similar, and their performances are comparable with those of both the considered references.

The purpose of this study was to compare different students' backgrounds and two different didactic methodologies to profitably teach computer animation in Italian schools of design and engineering. Teachers and instructors have long been engaged in discussions to define effective curricula for teaching computer animation. Various multidisciplinary and collaborative methodologies have been proposed. This manuscript assesses both the impact of a collaborative teaching approach and the curriculum. Two equivalent learning paths are compared; both of them encompass courses of photography, storytelling and computer animation and require prerequisites in 3D modeling and rendering. The learning path of the \"Systemic Design\" degree is taught by the collaborative Open Space Technology (OST) approach, whereas the path of \"Cinema and Media Engineering\" is taught more conventionally (independent courses). The results clearly show how effective teaching methodologies cannot completely compensate for a nontechnical background; on the other hand, as expected, students appreciate and can take advantage of collaborative forms of teaching.

A recent trend in human-computer interaction is to ease the creation of content such as apps and games via intelligent systems, allowing nonskilled users to define a given system's behavior through visual programming or simplified metalanguages. However, when the number of elements to be controlled increases, the complexity could become comparable to that of traditional coding strategies. This article addresses this issue by proposing a framework for automatically configuring a system's behavior based on user input and context information. Framework effectiveness has been tested in a game-creation scenario and used for automatically mapping user commands on virtual character actions based on a natural language description of the game scene. The use of semantics-based mapping reduces the effort and complexity linked with the configuration of the interaction logic, thus decreasing the number of commands needed for controlling the characters. The Web extra includes the questionnaire and full catalogue of descriptions collected

Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on \"Sensors for Entertainment\", developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored

The term Augmented Reality (AR) refers to a set of technologies and devices able to enhance and improve human perception, thus bridging the gap between real and virtual space. Physical and artificial objects are mixed together in a hybrid space where the user can move without constraints. This mediated reality is spread in our everyday life: work, study, training, relaxation, time spent traveling are just some of the moments in which you can use AR applications. This paper aims to provide an overview of current technologies and future trends of augmented reality as well as to describe the main application domains, outlining benefits and open issues

Advancements in input device and sensor technologies led to the evolution of the traditional human-machine interaction paradigm based on the mouse and keyboard. Touch-, gesture- and voice-based interfaces are integrated today in a variety of applications running on consumer devices (e.g., gaming consoles and smartphones). However, to allow existing applications running on desktop computers to utilize natural interaction, significant re-design and re-coding efforts may be required. In this paper, a framework designed to transparently add multi-modal interaction capabilities to applications to which users are accustomed is presented. Experimental observations confirmed the effectiveness of the proposed framework and led to a classification of those applications that could benefit more from the availability of natural interaction modalities

Robustly and efficiently tracking pedestrians in the infrared spectrum is a crucial requirement for a number of applications. At the same time, it is also particularly critical due to both the peculiarities of infrared images and pedestrian targets. In fact, low resolutions and high signal-to-noise ratios combined with extremely variable target signatures, chaotic trajectories, and frequent occlusions have forced researchers to develop ever more complex strategies characterized by a neat trade-off between tracking accuracy and computational complexity. Thus, most of the existing techniques might not be capable of ensuring real-time performances with a suitable degree of robustness, especially on limited-resource hardware used, e.g., in automotive or security scenarios. We present a technique that extends an extremely efficient tracking method originally tailored to targets that exhibit a clear and stable hot spot to allow it to deal with pedestrian targets by reusing its core components and integrating an occlusion detection and recovery mechanism. Experimental results obtained on public datasets confirmed that the devised method is able to obtain a robustness that is superior to that of other common approaches by maintaining the high tracking speed of the reference method

Public authorities have been designing and developing several initiatives for more than ten years in the attempt to guarantee an easy access and a wide offer of on-line services to citizens. Moreover, public authorities should guarantee a common heritage of data, accessible for any person at the same conditions. Despite of these initiatives, public bodies are still often dependent on software vendors. The European project OASIS aims to place the user at the center of a sustainable ecosystem where data, described by an open format, are shared among interoperable and reusable services. This approach allows public authorities to reduce costs, citizens to benefit of a wide range of high quality services and service providers to access to linked data for the development of new applications. Providers can also be part of the OASIS ecosystem, thus benefiting of an open a sustainable economic model. This manuscript describes in the details motivations behind the OASIS project and the portal Ozwillo, presents the platform architecture and discusses preliminary results.

Motion capture systems provide an efficient and interactive solution for extracting information related to a human skeleton, which is often exploited to animate virtual characters. When the character cannot be assimilated to an anthropometric shape, the task to map motion capture data onto the armature to be animated could be extremely challenging. This paper presents two methodologies for the automatic mapping of a human skeleton onto virtual character armatures. Kinematics chains of the human skeleton are analyzed in order to map joints, bones and end-effectors onto an arbitrary shaped armatures. Both forward and inverse kinematics are considered. A prototype implementation has been developed by using the Microsoft Kinect as body tracking device. Results show that the proposed solution can already be used to animate truly different characters ranging from a Pixar-like lamp to different kinds of animals

Here we give context to the Special Issue on \"Detection and Tracking of Targets in Forward-Looking InfraRed (FLIR) Imagery\" in Sensors. We start with an introduction to the role of infrared images in today's vision-based applications, by outlining the specific challenges that characterize detection and tracking in FLIR images. We then illustrate why selected papers have been chosen to represent the domain of interest, by summarizing their main contributions to the state-of-the-art. Lastly, we sum up the main evidence found, and we underline some of the aspects that are worthy of further investigation in future research activities

Assessment is a delicate task in the overall teaching process because it may require significant time and may be prone to subjectivity. Subjectivity is especially true for disciplines in which perceptual factors play a key role in the evaluation. In previous decades, computer-based assessment techniques were developed to address the above-mentioned challenges and to automatically grade students' work in a variety of educational fields. In this paper, the application of automatic assessment strategies in the unexplored domain of computer graphics is discussed. In particular, a tool that is designed to evaluate student assignments for a 3D computer animation course taught at Politecnico di Torino University is presented. During laboratory examination sessions, students are requested to individually operate on the open-source Blender suite and to recreate a 3D animation similar to a reference one. Student's output is assessed against a set of similarity indicators, which are specifically designed to capture the technical and perceptual factors that would be blended in a traditional teacher's evaluation. A comparison of the results that are achieved by the computer-based tool with grades assigned by visual inspection confirms the effectiveness of the designed approach and displays a high-quality concurrence between automatic and manual evaluations

Augmented reality (AR) is a well-known technology that can be exploited to provide mass-market users an effective and customizable support in a large spectrum of personal applications, by overlapping computer-generated hints to the real world. Mobile devices, such as smartphones and tablets, are playing a key role in the exponential growth of this kind of solutions. Nonetheless, there exists some application domains that just started to take advantage from the AR systems. Maintenance, repair, and assembly have been considered as strategic fields for the application of the AR technology from the 1990s, but often only specialists using ad hoc hardware were involved in limited experimental tests. Nowadays, AR-based maintenance and repair procedures are available also for end-users on consumer electronics devices. This paper aims to explore new challenges and opportunities of this technology, by also presenting the software framework that is being developed in the EASE-R3 project by exploiting reconfigurable AR procedures and tele-assistance to overcome some of the limitations of current solutions

The automatic extraction of objective features from paintings, like brushstrokes distribution, orientation and shape, could be particularly useful for different artwork analysis and management tasks. In fact, these features contribute to provide a unique signature of the artists' style and can be effectively used for artist identification and classification, artwork examination and retrieval, etc. In this paper, an automatic technique for unsupervised extraction of individual brushstrokes from digital reproductions of van Gogh's paintings is presented. Through the iterative application of segmentation, characterization and validation steps, valid brushstrokes complying with specific area and shape constraints are identified. On the extracted brushstrokes, several representative features can then be calculated, like orientation, length and width. The accuracy of the devised method is evaluated by comparing numerical results obtained on a dataset of digital reproductions of van Gogh's oil-on-canvas works with observations made by human subjects and with another recent approach for automatic brushstrokes analysis. Experimental tests showed that the devised methodology produces results that are rather close to those obtained by human subjects and, for some of the metrics considered, can provide improved performances with respect to alternative techniques

Tracking pedestrian targets in forward-looking infrared video sequences is a crucial component of a growing number of applications. At the same time, it is particularly challenging, since image resolution and signal-to-noise ratio are generally very low, while the nonrigidity of the human body produces highly variable target shapes. Moreover, motion can be quite chaotic with frequent target-to-target and target-to-scene occlusions. Hence, the trend is to design ever more sophisticated techniques, able to ensure rather accurate tracking results at the cost of a generally higher complexity. However, many of such techniques might not be suitable for real-time tracking in limited-resource environments. This work presents a technique that extends an extremely computationally efficient tracking method based on target intensity variation and template matching originally designed for targets with a marked and stable hot spot by adapting it to deal with much more complex thermal signatures and by removing the native dependency on configuration choices. Experimental tests demonstrated that, by working on multiple hot spots, the designed technique is able to achieve the robustness of other common approaches by limiting drifts and preserving the low-computational footprint of the reference method.

This survey of current job search and recruitment tools focuses on applying a computer-based approach to job matchmaking. The authors present a semantic-based software platform, LO-MATCH - developed in the framework of a European project on lifelong learning - that highlights future research directions. There are three related Web extras that provide supplemental material

Existing tracking methods designed for interacting with projection-based displays generally require visible artifacts to be introduced in the environment in order to guarantee effective stability and accuracy. For instance, in optical-oriented approaches, either the camera sensor or the reference pattern used for tracking are often located within the user's sight (or interfere with it), thus occluding portions of the scene or altering the perception of the virtual environment. Several ways to tackle these issues have been recently explored. Proposed approaches basically aim at making the presence of tracking references in the virtual space transparent to the user. However, such solutions introduce possibly critical constraints on required hardware or environment configuration. In this work, a novel tracking approach based on imperceptible fiducial markers is proposed. The approach relies on a hiding technique that allows digital images to be embedded in (and retrieved from) a projected scene by exploiting the properties of light polarization and additive color mixing. In particular, the virtual scene is obtained by overlapping the light beams of two projectors and by dealing with markers' hiding via color compensation. A prototype setup has been deployed, where interaction with a flat surface projection environment has been evaluated in terms of tracking accuracy and artifacts avoidance performance by using a consumer camera equipped with a polarizing filter. Although the performed tests presented in this article represent only a preliminary and a partial evaluation of the proposed approach, they provided encouraging results indicating that the proposed technique could be possibly applied in more complex interaction scenarios still with limited hardware requirements

Most virtual characters' animations are based on armatures to manipulate the characters' body parts (rigging). Armatures behave as the characters' skeletons, and their segments are referred to as bones. Each bone of the skeleton is associated with a well defined set of vertices defining the character' mesh (skinning), thus allowing animators to control movements and deformations of the character itself. This paper presents a natural and intuitive interface, which uses the Microsoft Kinect, to interactively control an armature by tracking body poses. Animators can animate virtual characters in real-time by their own body poses, thus obtaining realistic and smooth animations. Moreover, the proposed interface allows animators to save time with respect to the traditional animation technique based on keyframing. Different examples are used to compare the Kinect-based interface with the keyframing approach, thus obtaining both an objective and a subjective assessment.

This paper presents a new and challenging approach to the control of mobile platforms. Natural user interfaces (NUIs) and visual computing techniques are used to control the navigation of a quadrotor in GPS-denied indoor environments. A visual odometry algorithm allows the platform to autonomously navigate the environment, whereas the user can control complex manoeuvres by gestures and body postures. This approach makes the human-computer interaction (HCI) more intuitive, usable, and receptive to the user's needs: in other words, more user-friendly and, why not, fun. The NUI presented in this paper is based on the Microsoft Kinect and users can customize the association among gestures/postures and platform commands, thus choosing the more intuitive and effective interface

When moving in generic indoor environments, robotic platforms generally rely solely on information provided by onboard sensors to determine their position and orientation. However, the lack of absolute references often leads to the introduction of severe drifts in estimates computed, making autonomous operations really hard to accomplish. This paper proposes a solution to alleviate the impact of the above issues by combining two vision‐based pose estimation techniques working on relative and absolute coordinate systems, respectively. In particular, the unknown ground features in the images that are captured by the vertical camera of a mobile platform are processed by a vision‐based odometry algorithm, which is capable of estimating the relative frame‐to‐frame movements. Then, errors accumulated in the above step are corrected using artificial markers displaced at known positions in the environment. The markers are framed from time to time, which allows the robot to maintain the drifts bounded by additionally providing it with the navigation commands needed for autonomous flight. Accuracy and robustness of the designed technique are demonstrated using an off‐the‐shelf quadrotor via extensive experimental tests

Wireless communication advances have enabled emerging video streaming applications to mobile handheld devices. For example, it is possible to display and interact with complex 3D virtual environments on mobile devices that don't have enough computational and storage capabilities (e.g. smart phones, PDAs) through remote rendering techniques, where a server renders 3D data and streams the corresponding image flow to the client. However, due to fluctuations in bandwidth characteristics and limited mobile device CPU capabilities, it is extremely challenging to design effective systems for streaming interactive multimedia over wireless networks. This paper presents a novel approach based on a controller that can automatically adjust streaming parameters basing on feedback measures from the client device. Experimental results prove the effectiveness of the proposed solution in coping with bandwidth changes, thus providing high Quality of Service (QoS) in remote visualizations

This paper presents a system to track position and orientation of a generic mobile device equipped with a camera using a set of variable size fiducial markers. The system provides six degrees-of-freedom (6-DOF) by tracking fiducial markers through the camera and deriving the position and orientation of the device, thus making possible the implementation of innovative and affordable 3D user interfaces. The system has been integrated in a Cave Automatic Virtual Environment (CAVE) through the use of projectors and polarizers.

Automatic target tracking in forward-looking infrared (FLIR) imagery is a challenging research area in computer vision. This task could be even more critical when real-time requirements have to be taken into account. In this context, techniques exploiting the target intensity profile generated by an intensity variation function (IVF) proved to be capable of providing significant results. However, one of their main limitations is represented by the associated computational cost. In this paper, an alternative approach based on genetic algorithms (GAs) is proposed. GAs are search methods based on evolutionary computations, which exploit operators inspired by genetic variation and natural selection rules. They have been proven to be theoretically and empirically robust in complex space searches by their founder, J. H. Holland. Contrary to most optimization techniques, whose goal is to improve performances toward the optimum, GAs aim at finding near-optimal solutions by performing parallel searches in the solution space. In this paper, an optimized target search strategy relying on GAs and exploiting an evolutionary approach for the computation of the IVF is presented. The proposed methodology was validated on several data sets, and it was compared against the original IVF implementation by Bal and Alam. Experimental results showed that the proposed approach is capable of significantly improving performances by dramatically reducing algorithm processing time

Tracking targets in forward-looking infrared (FLIR) video sequences taken from airborne platforms is a challenging task. Several tracking failure modes can occur; in particular, discontinuities due to platform's motion can produce the so called ego-motion failure leading to unrecoverable errors in tracking the target. A novel ego-motion compensation technique for UAVs (unmanned aerial vehicles) is proposed. Data received from the autopilot can be used to predict the motion of the platform, thus allowing to identify a smaller region of the image (subframe) where the candidate target has to be searched for in the next frame of the sequence. The presented methodology is compared with a recently robust algorithm for automatic target tracking; experimental results show that the proposed motion estimation approach helps to improve performance both in terms of frames processed per second (targets are searched in smaller regions) and in terms of robustness (targets are correctly tracked for all the sequence's frames)

With the tremendous growth of information available to end users through the Web, search engines come to play ever a more critical role. Nevertheless, because of their general-purpose approach, it is always less uncommon that obtained result sets provide a burden of useless pages. The next-generation Web architecture, represented by the Semantic Web, provides the layered architecture possibly allowing overcoming this limitation. Several search engines have been proposed, which allow increasing information retrieval accuracy by exploiting a key content of Semantic Web resources, that is, relations. However, in order to rank results, most of the existing solutions need to work on the whole annotated knowledge base. In this paper, we propose a relation-based page rank algorithm to be used in conjunction with Semantic Web search engines that simply relies on information that could be extracted from user queries and on annotated resources. Relevance is measured as the probability that a retrieved resource actually contains those relations whose existence was assumed by the user at the time of query definition

This framework lets users easily and effectively use desktop applications on mobile devices without any redesign. An automatically generated description of the original interface lets the original application be recreated and migrated to nomadic scenarios. Users can also customize interfaces to suit their needs and match a device's capabilities

Scientific research and practical applications of solar physics require data and computational services to be integrated seamlessly and efficiently. The European Grid for Solar Observations (EGSO) leverages Grid-oriented concepts and technology to provide a high-performance infrastructure for solar applications. In this paper, an architecture for a data brokerage service is proposed. Brokers interact with providers and consumers in order to build a profile of both parties. In particular, a broker interacts with providers in order to gather information on the data potentially available to consumers, and with the consumers in order to identify the set of providers that are most likely to satisfy specific data needs. The brokerage technique is based on a multi-tier management of metadata

Mobile devices such as Personal Digital Assistants, Tablet PCs, and cellular phones have greatly enhanced user capability to connect to remote resources. Although a large set of applications are now available bridging the gap between desktop and mobile devices, visualization of complex 3D models is still a task hard to accomplish without specialized hardware. This paper proposes a system where a cluster of PCs, equipped with accelerated graphics cards managed by the Chromium software, is able to handle remote visualization sessions based on MPEG video streaming involving complex 3D models. The proposed framework allows mobile devices such as smart phones, Personal Digital Assistants (PDAs), and Tablet PCs to visualize objects consisting of millions of textured polygons and voxels at a frame rate of 30 fps or more depending on hardware resources at the server side and on multimedia capabilities at the client side. The server is able to concurrently manage multiple clients computing a video stream for each one; resolution and quality of each stream is tailored according to screen resolution and bandwidth of the client. The paper investigates in depth issues related to latency time, bit rate and quality of the generated stream, screen resolutions, as well as frames per second displayed

Global and local histogram equalization (HE) proved to be effective techniques for contrast enhancement. Local HE allows to achieve high contrast enhancement rates but its high computational complexity limits its applicability in many resource constrained scenarios. On the contrary, global HE complexity is relatively low but enhancement rate is often unsatisfactory. Recently, an algorithm exploiting a low-pass filter (LPF) mask to obtain a partially overlapped sub-block HE effect (POSHE) has been presented. POSHE allows to produce the high local HE contrast with the simplicity of global HE. In this paper a generalization of POSHE approach exploiting cascaded multistep binomial filtering HE (CMBFHE) in order to get the same LPF mask is proposed. By relying on the same filter mask, contrast enhancement capability of CMBFHE is exactly the same of POSHE. Additionally, results show that a significant speedup with respect to the previous fastest method is achieved because of the efficient implementation of the filtering approach; moreover hardware implementations can be effectively designed. This makes CMBFHE a suitable solution in all those consumer electronics related environments including camcorders, digital cameras and video surveillance where on-the-fly local-like contrast enhancement is required

This paper describes a hybrid distributed architecture, based on the JXTA technology, for searching and discovering data in a federation of solar observation archives. This work has been developed within the European project EGSO (European Grid of Solar Observations) with the intent of studying and analyzing a set of technologies and showing the brokerage capabilities of a highly controlled distributed network topology. Three roles have been identified: providers that contain data and metadata, brokers that manage providers and user queries, and consumers/clients. JXTA is used to develop all network system functionalities, while a native XML database is used to store resource descriptions.

The visualization of dense vector fields has important applications for scientific purposes. Beyond the standard methods, such as arrows and particle tracing, texture-based methods are able to show almost all the details of a field. This paper presents the Thick Oriented Stream-Line (TOSL) algorithm, which can show direction, orientation and local flow speed even for dense vector fields by simulating the convolution process. A practical comparison of the performances of TOSL vs. other visualizations algorithms (LIC and fastLIC) shows that the proposed algorithm can provide output textures faster than the other considered techniques.

his paper presents a new algorithm to generate ray-cast CSG animation frames. We consider sequences of frames where only the objects can move; in this way, we take advantage of the high screen area coherence of this kind of animation. A new definition of bounding box allows us to reduce the number of pixels to be computed for the frames after the first. We associate a CSG subtree and two new flags, denoting if the box has changed in the current frame and if it will change in the next frame, with each box. We show with three examples the advantages of our technique when compared with an algorithm which entirely renders each frame of an animation. Intersections with CSG objects may be reduced to about one-fifth, while the rendering may be computed up to four times faster for the test sequences

The generation of 3-D solid objects, and more generally solid geometric modelling, is very important in Computer Aided Design (CAD). An important role is played by the Constructive Solid Geometry (CSG) representation scheme. IN CSG, objects are described by trees of Boolean operations on half-spaces or boundaries of primitive solids. The study of techniques to speed up the rendering of scenes modelled with the CSG scheme is an attractive field of research; in this paper we propose a new algorithm which reduces the computational complexity for ray casting approaches. Our strategy identifies a set of areas on the plane of view where the rays starting from the observer have to be traced; for each zone, only a portion of the entire CSG tree has to be considered for intersection tests, instead of the whole database of the primitive objects. A comparison of our algorithm with a ray caster that adopts bounding volume hierarchies and with a freeware ray tracer called POV-Ray shows that, for the examples considered, we may reduce the intersection tests to one third of those performed when standard optimizations are adopted.

The authors present a parallel algorithm for fast rendering. A set of zones which can be concurrently processed is identified; this set is split into a number of subsets equal to the number of available processors. Each processor renders, in parallel with the others, a zone of its set

Several computer graphics algorithms (such as ray-tracing) heavily relate their performances to the efficiency of the tests of intersection between the rays of a light source and the objects of a synthetic scene. Some solid modelling and robotics algorithms need also to test quickly the possible interferences of the different parts of a system such as the arms of different robots. To speed-up the test, the free shape objects to be tested are encapsulated into boxes and the test starts by performing a check on overlapping of the bounding boxes, thus producing a section of the space where an intersection can occur. Successively, if the boxes overlap, the test continues on the original free shape objects, but only in the portion of the 3D-space resulting from the first step. The authors present a simple, fast and efficient algorithm (called the `bounding boxes group' method) to compute a tight bounding entity of a complex object modelled in the constructive solid geometry (CSG). If no upper limit is set to the number of elements of each bounding box group, the algorithm is shown to achieve the tightest possible solution. Algorithms are also presented which allow a reduction of the number of bounding elements but still provide a satisfactory and tight encapsulation

Brain injury can cause a variety of physical effects and cognitive deficits. Although it has not yet been systematically adopted in clinical settings, virtual reality promises to be an excellent therapeutic tool for regaining both locomotor and neurological capacities. This work presents the design and implementation of VR2 (Virtual Reality Rehabilitation), a customizable rehabilitation framework intended to enable the creation of motivating rehabilitation scenarios based on an ecologically valid semi-immersive system. Following the implementation phase, a study to test the acceptability of VR2 in a group of subjects with cerebral lesions was conducted to investigate the usability of the framework. The group consisted of 11 people from 22 to 70 years of age, who were divided into two groups depending on the chronicity of disorder. The adequacy of the interface between patient and system was verified through questionnaires containing subjective questions, which revealed good overall acceptance and enjoyment of the tool. Moreover, to obtain early results useful for tuning the overall system in preparation for rigorous clinical trials, a set of preliminary cognitive tests concerning the rehabilitation protocol was conducted within the same group. Although the preliminary findings are promising and reveal a positive trend in neurocognitive investigations, the system should undergo clinical trials before being used in real clinical settings.

The preparation of a set for a television production is a complex work; usually, several objects have to be manually placed in the environment and the configuration might be changed many times before finding the final set up. This configuration phase can be expensive and time consuming when large and heavy objects have to be moved. In order to tackle this issue, virtual sets allow the director of production to create virtual scenes before placing real objects. This paper proposes an alternative approach based on augmented reality technologies: objects of the scene are computer generated assets, which can be placed and manipulated in a real environment. With respect virtual sets, the proposed solution allows the director to move in a real scene enriched by computer-generated objects to be placed in the environment. The user wears an AR headset and manipulates objects by a tablet. The proposed system was evaluated by a group of 9 testers, which had to create an augmented TV set. Subjective and objective parameters have been used to assess the system usability.

In the last years, robotic telepresence solutions have received a significant attention from both the commercial and academic worlds, due to their ability to allow people to feel physically present at a remote place and move in it. Operating a mobile robot with some autonomous capabilities from distance can enable a wide range of mass-market applications, encompassing teleconferencing, virtual tourism, etc. In these scenarios, the possibility to interact with the robot in a natural way becomes of crucial importance. The aim of this paper is to investigate, through a comparative analysis, the usability of two major approaches used today for controlling telepresence robots, i.e., keyboard and point-and-click video navigation. A control system featuring the above interfaces plus a combination of the two has been developed, and applied to the operation of a prototype telepresence robot in an office scenario. The system additionally includes functionalities found in many research and industry solutions, like map-based localization and \"augmented\" navigation. Then, a user study has been performed to assess the usability of the various control modalities for the execution of some navigation tasks in the considered context. The study provided precious indications to be possibly exploited for guiding next developments in the field.

Augmented Reality (AR) is expected to change the way we play, by transforming the world around us in an incredibly rich gaming environment. In this work, connected robots and natural interaction means are combined with projected AR to create a gaming experience more physical and engaging.

Interacting with 3D contents is a challenging task and the implementation of natural and effective interfaces is usually demanded to computer programmers. On the other hand, exhibit designers would greatly take advantage of graphic tools able to completely hide technical details and code programming. This paper presents a graphic editor where interface designers can intuitively link objects, gestures and actions together, without needing computer science skills. Tests show the advantages of the proposed solution both for experts and beginners; moreover, a real example concerning the exhibit of the digital Nefertiti's bust within a holographic case controlled by hand gestures has been implemented.

The increasing popularity of robotics and related applications in modern society makes interacting and communicating with robots of crucial importance. In service robotics, where robots operate to assist human beings in their daily life, natural interaction paradigms capable to foster an ever more intuitive and effective collaboration between involved actors are needed. The aim of this paper is to discuss activities that have been carried out to create a 3D immersive simulation environment able to ease the design and evaluation of natural human-robot interfaces in generic usage contexts. The proposed framework has been exploited to tackle a specific use case represented by a robotics-enabled office scenario and to develop two user interfaces based on augmented reality, speech recognition as well as gaze and body tracking technologies. Then, a user study has been performed to study user experience in the execution of semi-autonomous tasks in the considered scenario though both objective and subjective observations. Besides confirming the validity of the devised approach, the study provided precious indications regarding possible evolutions of both the simulation environment and the service robotic scenario considered.

Several virtual and augmented reality tasks involve users in hands-free interactions; in this case, speech-based systems are often preferred for their intuitiveness and naturalness. On the other hand, the robustness of this kind of interfaces can be an issue, thus affecting both the usability and the user experience, when they are used in noisy environments. This paper proposes a one switch interface triggered by vocal commands: three different scanning algorithms are tested. With this kind of interface users can sequentially select the desired command, thus improving the robustness of traditional speech recognition-based interfaces. Latency time is an issue for one switch interfaces, but it is shown how a bidirectional scanning algorithm based on a non binary switch can strongly mitigate this problem. Vocal one switch (VOS) interfaces are compared with a traditional multi-word speech interface both objectively (in terms of robustness and efficiency) and subjectively (user feedback).

Drone-based delivery of goods could become a reality in the near future, as witnessed by the increasing successful experiences in both research and commercial fields. In this paper, a prototype system exploiting a do it yourself quad copter drone for delivering products is proposed. On the one hand, the hardware choices made in order to limit risks arising from autonomous delivery are presented. On the other hand, a framework for orders placement and shipment is shown. The advantages of a system like the one described in this paper are mainly related to an increased delivery speed, especially in urban contexts with traffic, to the possibility to make deliveries in areas usually difficult to be reached, and to the drone's ability to autonomously carry out consignments. A practical use case, in which the proposed system is used for delivering drugs (an application in which the need to quickly receive the good might be particularly important) is shown. Nevertheless, the proposed prototype could be employed in other contexts, such as take-away deliveries, product shipments, registered mail consignments, etc

The aim of the project is to design and develop a system, a framework and a \"cultural heritage storytelling model\" to ease the exploitation of transmedia storytelling in the promotion of cultural heritage, through the reuse of European digital cultural assets. It will provide institutions and enterprises with a powerful environment to design and develop transmedia contents and to improve the promotion of their activities. A transmedia model will be applied in order to engage citizens and tourists in narrative experiences, online and in physical spaces (test sites will be equipped in Greece, Italy, Bulgaria), improving their knowledge of values deeply connected with European identity, such as work, social equality, natural resources exploitation. This objective is accomplished through the design of a fictional open and expandable narrative universe created through research and historical documentation. Alternate reality Games, Augmented Reality, Game App, Immersive cinematic and Virtual reality will be among the technologies applied in StoryTECH. A Semantic Reasoner will be designed and developed to improve the reuse of digital archives by a wider audience and to provide authoring support to transmedia storytelling of cultural heritage. StoryTECH will develop also an Animation Framework in order to ease the production of multimedia contents by small institutions and SME.

This paper studies the opportunities coming from the use of consumer devices like smartphones and tablets to perform maintenance and assembly procedures with Augmented Reality (AR). Pros and cons are evaluated by comparing completion times and errors made while executing a maintenance procedure with an AR-based tool and paper-based instructions

The availability of annotated multimedia contents is a crucial requirement for a number of applications. In the context of education it could support the automatic summarization of recorded lessons or the retrieval of learning material. In the field of entertainment, it could serve to recommend audio and video resources based on user's attitudes. In this work, a framework supporting video viewing experience augmentation on mobile devices by means of image- and text-based annotations extracted on-demand from Wikipedia is presented. Speech recognition is exploited to periodically get text snaps from the audio track of the video currently displayed on the mobile device, while query-by-images is used to generate a text summary of extracted video frames. Keywords obtained are treated by semantic techniques to find named entities associated with the multimedia contents, which are then superimposed to the video and displayed to the user in a synchronized way. Promising results obtained with a prototype implementation showed the feasibility of the proposed solution, which could be possibly combined with other systems, e.g., providing information about user's location, preferences, etc. to build up more sophisticated context-aware applications

Augmented Reality (AR) has been proved to be an effective tool to improve and enhance the learning experience of students. On the other hand, issues regarding the inflexibility of AR contents can strongly limit the usability of AR applications in education. This paper presents results obtained by using the AR framework designed and developed for the EASE-R3 European project and focused on the generation of maintenance procedures for machine tools. The high system flexibility allows instructors to easily make maintenance procedures suitable for the skill level of technicians to be trained. A case study is presented and results gathered so far analyzed and assessed

This paper presents a new architecture supporting the development of enhanced reading applications. It exploits the thin-client paradigm to let the authors produce interactive components to be embedded in today e-books, thus enriching text contents with focused and customized graphics widgets generated from the interface of existing programs running in remote

The widespread adoption of mobile devices is giving everyone access to augmented reality systems, possibly involving a huge number of people in AR-based apps, with a pervasive social impact that cannot be neglected. AR systems are becoming affordable to everyone and especially useful in the maintenance field. This report aims to describe in a clear and accessible way the workflow to design and develop an augmented reality (AR) application for supporting maintenance procedures. The main focus of this paper is the evaluation of markerless tracking systems, as they could provide environment-independent solutions. The tests performed on a real use case outline the robustness of 3D CAD tracking with respect to other solutions

Motion capture systems provide an efficient and interactive solution for extracting information related to a human skeleton, which is often exploited to animate virtual characters. When the character can- not be assimilated to an anthropometric shape, the task to map mo- tion capture data onto the armature to be animated could be extremely challenging. This paper presents a novel methodology for the automatic mapping of a human skeleton onto virtual character armatures. By ex- tending the concept of graph similarity, joints and bones of the tracked human skeleton are mapped onto an arbitrary shaped armature. A pro- totype implementation has been developed by using the Microsoft Kinect as body tracking device. Preliminary results show that the proposed so- lution can already be used to animate truly different characters such as a Pixar-like lamp, a fish or a dog.

In this paper, a framework allowing to extend the applicability of natural user interaction techniques to existing programs is presented. Body gestures captured by a depth camera are mapped to application commands, and a wide set of common desktop applications can be controlled without any code rewriting

In this work, the energy cost for 3D graphics processing on consumer devices is analyzed, and a framework mixing local and remote visualization techniques to trade off between rendering performances and power saving is proposed

The evolution of input device technologies led to identification of the natural user interface (NUI) as the clear evolution of the human-machine interaction, following the shift from command-line interfaces (CLI) to graphical user interfaces (GUI). The design of user interfaces requires a careful mapping of complex user \"actions\" in order to make the human-computer interaction (HCI) more intuitive, usable, and receptive to the user's needs: in other words, more user-friendly and, why not, fun. NUIs constitute a direct expression of mental concepts and the naturalness and variety of gestures, compared with traditional interaction paradigms, can offer unique opportunities also for new and attracting forms of human-machine interaction. In this paper, a kinect-based NUI is presented; in particular, the proposed NUI is used to control the Ar.Drone quadrotor

In recent years there has been an increasing effort in investigating integrated solutions to reduce energy consumption levels in different domains. In this perspective, tools thought as a support for the simulation and experimentation of energy saving strategies could constitute a valid help both in the design and validation phases. Within the above scenario, this paper presents a framework for monitoring, simulating and controlling energy-aware street lighting systems capable of optimizing their energy consumption levels based on environmental conditions and established lighting policies. The devised system allows operators to visually inspect (and control) the power saving impact of specific dimming rules in both monitored and simulated environments through the use of advanced 3D vision and interaction capabilities. In fact, a virtual interface is able to recreate the lighting effect within digital city environments, which can be explored by using immersive stereoscopic techniques. Moreover, natural user interfaces based on the recognition of user gestures and poses and voice commands are exploited to improve virtual navigation of the lighting infrastructures. By addressing all the presented aspects, the proposed system aims at constituting an effective tool to develop and analyze energy saving solutions in the domain of (but not necessarily limited to) future public street lighting.

This paper presents a framework for controlling remote applications by means of personalized multi-touch interfaces. The designed framework allows end-users to fully personalize the mapping between gestures and input commands. A two-tier architecture has been developed. A formal description of the original interface is automatically generated at the server side to identify a set of available actions for controlling existing applications. The client is in charge of loading the description of the target application, allowing the user to shape the preferred mapping between gestures and actions. Finally, the server converts the identified actions into one or more commands understandable by the original computer interface. The implementation of the system for this work specifically relies on handheld multi-touch devices. Test results are encouraging, both from an objective and a subjective point of view; indeed, the designed framework resulted to outperform a traditional GUI both in terms of number of actions to perform a task and average completion time

Cloud computing is regarded to as an impressive technology, as software and hardware resources become invisible to the users (they \"fade\" in the cloud), and they replaced by services. In this sense, cloud computing can be considered as an evolution of former virtualization approaches, with service providers delivering on-demand access to various back-end frameworks and front-end applications. This approach requires to strongly trust these providers, as users are forced to give up control on programs and data that were previously hosted on their machines. A possible way to alleviate this drawback could be to enable users \"participate\" to the cloud with their own applications, thus creating \"personal\" clouds, which could be even shared with other users. In this paper, we present a prototype implementation of the above idea, which consists of a framework that allows today's applications to be put into the cloud by exploiting user interface automation and accessibility information embedded in modern window-based graphics toolkits

This paper presents a framework enabling 6-DOF interaction with generic visualization environments through mobile devices. Features computed on image frames captured by on-board camera are used to develop an affordable and effective 3D user interface

La realizzazione di reti per illuminazione stradale basate su tecnologie innovative e su soluzioni di monitoraggio e controllo intelligenti può indubbiamente contribuire ad una gestione più razionale ed efficiente delle risorse energetiche. In questo lavoro viene presentata una piattaforma software basata su soluzioni web e su tecniche di computer grafica e realtà virtuale progettata per la simulazione e la supervisione remota di infrastrutture pubbliche di illuminazione basate su punti luce a LED intelligenti in uno scenario di città digitale

The labor market is today characterized by a marked competitiveness. The ability to accurately choose the right education and training paths leading to the acquisition of the right competences required for a given job position, as well as the capability to properly select human resources based on precise job requirements are becoming more and more key factors to success. Nevertheless, the comparison of education opportunities generally requires a manual analysis of huge qualification descriptions and course syllabi, whereas staff selection (or job seeking activities) often relies on non-automated processes mainly based on an extensive check of applicants' curriculum vitae (or of possible job offers). The above tasks are extremely time consuming and, given the large amount of information to be considered, they also risk to provide unsatisfactory results. In this paper, the above issues are addressed in the perspective of semantic technologies. In particular, a webbased application is presented, which exploits ontological descriptions and tag cloud-based visualization strategies to generate a direct representation of the overlap between learners' needs and existing education and training paths, as well as between job seekers' profiles and company requirements. This way, potential users are provided with an effective support for matching job and study offers with corresponding demands

The application of computer graphics techniques to the creation of digital city environments is receiving increasing attention in the last years. This is in part due to the fact that, by mixing heterogeneous components like geographic information systems, virtual model repositories and smart sensor networks, digital cities are expected to be able to allow the various stakeholders involved in urban planning and management to effectively design, monitor and operate present as well as future city infrastructures. In this work, a software framework exploiting web and virtual reality technologies to remotely manage a network of LED-based smart luminaries is presented. The integration of public lighting systems into the digital city picture is considered of particular interest, since through these novel solutions, forthcoming intelligent lighting networks could be supervised in an integrated way, and specific safety, security and energy saving policies could be easily implemented

This paper describes a novel method to detect false alarms in target tracking applications based on image-based feature descriptors. The number of matches between the local feature descriptors in the reference target and in the candidate target is used to assess the reliability of the tracking algorithm used and, in case, to activate a suitable recovery mechanism. The proposed approach has been evaluated on a series of Forward Looking Infrared (FLIR) sequences provided by the U.S. Army Aviation and Missile Command (AMCOM)

A wide variety of remotely controlled mobile robots have been developed in the past. Despite the evolution in robotics functionalities, not much effort has been made to customize control interfaces to meet user preferences and needs. General users can find difficulties in controlling mobile robots by standard interfaces. On the other hand, recent advances in multi-touch devices now allow researchers to design and implement intuitive and user friendly interfaces. This paper presents recent efforts to control mobile platforms by using customizable multi-touch gestures drawn on a commonly available hand-held device. In particular, a live stream video coming from an on board camera allows both to automatically and manually control the platform to accomplish target tracking and following tasks

This paper presents a solution to control mobile robots by using customizable haptic and multi-touch gesture interfaces on handheld devices. Images coming from a camera allows both to automatically and manually control the robot

Wireless communication advances enable emerging video streaming applications to mobile handheld devices. For example, it is possible to show and interact with a complex 3D virtual environment on a \"thin\" mobile device through remote rendering techniques, where a rendering server is in charge to render 3D data and stream the corresponding image flow to the demanding client. However, due to bandwidth fluctuating characteristics and limited mobile device CPU capabilities, it is extremely challenging to design effective systems for interactive streaming multimedia over wireless networks. This paper presents a novel approach based on a controller able to automatically adjust streaming parameters basing on feedback measures coming back from the client device. Experimental results prove the effectiveness of the proposed solution to cope with bandwidth changes, thus providing a high Quality of Service (QoS) in remote visualizations.

Students and workers mobility in the European scenario represents today a big challenge. During the last years, several initiatives have been carried out to deal with the above picture, being the European Qualication Framework (EQF), a common architecture for describing qualications, one of the most signicant. In parallel, several research activities were established with the aim of exploiting semantic technologies for qualication comparison in the context of human resources acquisition. In this paper, the EQF specications are applied in a practical scenario to develop a ranking algorithm allowing for qualication comparison on the basis of knowledge, skill and competence concepts, potentially aimed at supporting European employers during the recruitment phases

A new category of devices, known as Personal Digital Assistant (PDA), has become increasingly widespread since the end of the nineties. A large number of software applications have been developed for PDAs, but high-quality 3D graphics still remain beyond the computational capability of these devices.This paper tackles this issue by proposing a generic solution for hardware-accelerated remote rendering on cluster. The rendering task is submitted to a PC/workstation cluster (each cluster machine is equipped by a graphics accelerator) by means of the Chromium architecture. Each machine renders a part of the image that is then reassembled and sent to the PDA via a software bridge. On the PDA side, the user can explore the scene using an ad-hoc navigation interface.The proposed solution allows to display extremely realistic and complex models in an interactive way. Moreover, our architecture does not depend on commercial solutions/products and can be easily modified in order to better fulfill requirements of specific applications

Computationally intensive applications often require the employment of parallel/distributed solutions in order to strongly reduce execution times. Workstations and PCs connected by a fast local network provide effective, low-cost, and general purpose solutions that are quickly replacing special purpose proprietary architectures for a wide spectrum of disciplines. The issue to monitor the performance (fundamental to check the efficiency of a distributed application) of cluster architectures is addressed in this work. This paper presents a multi-channel architecture for remote monitoring-management tailored to display information on PDA devices. Users can remotely monitor the system critical activities and cluster resources utilization; moreover, we provide the possibility to perform some management tasks (for instance, shutdown and reboot) useful for maintaining the integrity of the system and to harness the full cluster potential.

Several algorithms can effectively represent vector fields by texture-based representations, visualizing at most all information on the field: direction, orientation, and local magnitude. An open problem still remains the mapping on textures of adjunctive information such as temperature, pressure, and so on, without using colors. This article addresses this issue by proposing a technique to add a scalar value denoting streamlines by means of different levels of contrast. Both streamline starting tones and the range of tones depend on the scalar value to be mapped; in this way, areas visualized by different contrast levels are represented. Two examples show the effectiveness of the proposed technique

In this paper a PVM-based distributed platform of the well known REYES rendering architecture developed byPix ar is presented. This work effectivelyt ackles issues related to load balancing and memory allocation by a master-slave paradigm. In particular, the rendering is distributed performing both an image and an object space subdivision; in this way, low memory resources are necessary to the slave side. Examples show the effectiveness of the proposed work.

In recent years, virtual reality has shown all its potential in a large spectrum of applications: training, simulation, CAD, and so on. Although existing technologies allow the creation of immersive virtual reality browsing experiences, little has been devoted to applying this new tool to electronic commerce (e-commerce) since almost all e-commerce web sites present products in a 2D on-line catalog. In this paper we present 3D-dvshop, a dynamic 3D virtual shop: a user can build his or her own shop, choosing a set of products that will be dynamically placed in a collection of specially created \"rooms\". The use of technologies such as VRML and Java allows full 3D interaction with products. In this way, the browsing experience can be more natural, attractive, realistic, and fun

Visualization of vector data produced from application areas such as computational fluid dynamics (CFD), environmental sciences, and material engineering is a challenging task. Texture-based methods reveal to be e ective, versatile, and suitable for a large spectrum of applications since they allow to obtain high resolution output textures where direction, orientation, and magnitude of the ow can be displayed. In this paper we present a new method called B 2 LIC, which allows both to characterize and visualize interesting structures in the ow and to map two additional scalar values in output textures by bumps, depressions, and shadows, leaving colors for further information mapping. B 2 LIC is the natural and direct evolution and the improvement of the BLIC (Bumped LIC) algorithm, which is able to map just one scalar value by the bump mapping technique. Some examples show how the proposed method can e ectively allow to map two additional scalar values such as: temperature, vorticity, pressure, and so on, adding new and additional representation capabilities to dense texture-based visualization methodologies.

We present a new and efficient algorithm to generate rendered animation. With respect to the approaches known in the existing literature, our algorithm does not generate the animated sequences frame-by-frame, but it renders only the parts which change between two following frames by exploiting the frame-to-frame coherence. We show, with practical examples, the efficiency of the proposed technique. In the proposed examples the animation can be rendered, with our method, at least eight times faster than by using a straightforward frame-by-frame technique

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