Anderson Maciel

Anderson Maciel
Universidade Federal do Rio Grande do Sul | UFRGS · Institute of Informatics

Ph. D.

About

147
Publications
44,548
Reads
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1,116
Citations
Citations since 2016
70 Research Items
730 Citations
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2016201720182019202020212022050100150
Introduction
I've been working in the field of Visual Computing and Human-Computer Interaction, with current and recent projects in Computer Graphics, Virtual and Augmented Reality, Computer Assisted Medical Applications, Physics-based Simulation of the Human Anatomy, Surgery Simulation.

Publications

Publications (147)
Conference Paper
Full-text available
The efficient, natural and precise selection and manipulation of nearby objects in 3D environments is yet a challenge in the area of 3D interaction. Robot teleoperation is a potential application field for this kind of interaction and a difficult task. In part due to the low quality of the information delivered to the operator, but also because of...
Article
Full-text available
The FLS training tool box has now been adopted by the Society of Gastrointestinal Endoscopic Surgeons (SAGES) as an official training tool for minimally invasive procedures. To overcome the limitations of the physical FLS training tool box, we have developed a Virtual Basic Laparoscopic Skill Trainer (VBLaSTTM) system, which is a 3D simulator that...
Article
Full-text available
In this paper, we introduce a novel "dynamic point" algorithm for computing the interaction of a line-shaped haptic cursor and polygonal surface models which has a near constant complexity. The algorithm is applied in laparoscopic surgery simulation for interaction of surgical instruments with physics-based deformable organ models.
Article
Full-text available
Using virtual environments (VEs) is a safer and cost-effective alternative to training people in different contexts. Immersive Virtual Reality (VR), combined with game aspects, have the potential to improve the user experience in the VE by increasing realism, engagement, and motivation. In education, there is a consensus about its contribution in t...
Conference Paper
We present a visuo-haptic interaction approach that augments the visual experience of graphic data visualization with meaningful vibrotactile information. The user of our interface explores charts and graphs on a conventional video monitor or other displays, e.g. projection, or printed paper. When a user touches the data visualization, an array of...
Chapter
In the context of raising awareness to assistive technologies, we propose a gaming experience that allows users to embody having a visual impairment. By occluding the user’s vision and providing spatialized audio and passive haptic feedback, allied with a speech recognition digital assistant, our goal is to present a multi-sensory experience that o...
Conference Paper
Full-text available
In the context of promoting a sense of empathy for the difference in people without disabilities, we propose a gaming experience that allows users to embody having a visual impairment. By occluding the user’s vision and providing spatialized audio and passive haptic feedback, allied with a speech recognition digital assistant, our goal is to offer...
Article
The Visualization, Interaction and Simulation Laboratory (VISLab) is part of the Computer Graphics, Image Processing and Interaction research group, which started its activities in 1978 developing projects mainly on rendering and animation. Along the years, as new researchers joined the group, new research fields such as image acquisition and analy...
Conference Paper
Full-text available
The Visualization, Interaction and Simulation Laboratory (VISLab) is part of the Computer Graphics, Image Processing and Interaction research group, which started its activities in 1978 developing projects mainly on rendering and animation. Along the years, as new researchers joined the group, new research fields such as image acquisition and analy...
Chapter
Since immersive VR devices have become commodities, immersive environments appear as a new tool in the development of high-fidelity prototypes of systems in which the user interaction relies on expensive or unusual hardware, e.g., industrial systems. However, there is not enough evidence that the interface of a complex system and its VR counterpart...
Article
In electrical engineering, hardware experts often need to analyze electromagnetic radiation data to detect any external interference or anomaly. The field that studies this sort of assessment is called electromagnetic compatibility (EMC). As a way to support EMC analysis, we propose the use of Augmented Situated Visualization (ASV) to supply profes...
Conference Paper
Full-text available
Whenever accessing indoor spaces such as classrooms or auditoriums , people might attempt to analyze and choose an appropriate place to stay while attending an event. Several criteria may be accounted for, and most are not always self-evident or trivial. This work proposes the use of data visualization allied to an Augmented Reality (AR) user inter...
Conference Paper
Full-text available
In the context of promoting empathy among people without disabilities, we propose an application to allow users to experience having an amputated arm. By providing both visual and haptic feedback, our application offers a multisensory experience to enhance the sense of embodiment. The user of our application should still feel their real limb attach...
Conference Paper
Full-text available
In EMC testing, 3D electromagnetic field data often needs to be visually analysed by an expert in order to detect product defects or unwanted interference between multiple devices. In this sense, the present work proposes the use of data visualization techniques allied to an Augmented Reality user interface to provide information that helps profess...
Conference Paper
Full-text available
This paper summarizes our study of tactile languages in humancomputer interaction. We intended to analyze how the choices made during the design process of tactile vocabularies would affect the user performance on an interactive task. Therefore, we have developed and tested different sets of tactile signals for aid navigation in virtual environment...
Article
Full-text available
Tangible objects are used in Virtual Reality (VR) and Augmented Reality (AR) to enhance haptic information on the general shape of virtual objects. However, they are often passive or unable to simulate rich varying mechanical properties. This paper studies the effect of combining simple passive tangible objects and wearable haptics for improving th...
Poster
Full-text available
The present work proposes the use of data visualization techniques allied to an Augmented Reality (AR) user interface to provide information for users to define the most convenient location to sit down at an event. This accounts for different sets of arbitrary demands by projecting 3D information directly atop the seats. The users can also rearrang...
Preprint
Full-text available
Motor imagery Brain-Computer Interface (MI-BCI) enables bodyless communication by means of the imagination of body movements. Since its apparition , MI-BCI has been widely used in applications such as guiding a robotic prosthesis, or the navigation in games and virtual reality (VR) environments. Although psychological experiments, such as the Rubbe...
Conference Paper
The present work proposes the use of data visu-alization techniques allied to an Augmented Reality (AR) user interface to provide information for users to define the most convenient location to sit down at an event. This accounts for different sets of arbitrary demands by projecting 3D information directly atop the seats. The users can also rearran...
Chapter
When traveling, a very common issue is to ask for the help of a stranger to take a photo on a touristic spot. Indeed, often the results of this short collaboration are not as previously imagined. In this paper, we introduce the concept of instant rephotography, a technique based on a simple and intuitive user interface, and in an efficient and low...
Conference Paper
Motor imagery Brain-Computer Interface (MI-BCI) is a paradigm widely used for controlling external devices by imagining bodily movements. This technology has inspired researchers to use it in several applications such as robotic prostheses, games, and virtual reality (VR) scenarios. We study the inclusion of an imaginary third arm as a part of the...
Conference Paper
Sketching was traditionally a 2D task. Even when the new generation of VR devices allowed to sketch in 3D, the drawn models remained essentially static representations. In this paper, we introduce a new physics-inspired sketching technique built on the top of Position-based Dynamics to enrich the 3D drawings with dynamic behaviors. A particle-based...
Chapter
Full-text available
Navigation in real environments is arguably one of the primary applications for the mixed reality (MR) interaction paradigm. We propose a wearable MR system based on off-the-shelf devices as an alternative to the widespread handheld-based GPS navigation paradigm. Our system uses virtual holograms placed on the terrain instead of the usual heads-up...
Conference Paper
Full-text available
We present an assessment of asymmetric interactions in Collabora-tive Virtual Environments (CVEs). In our asymmetric setup, two co-located users interact with virtual 3D objects, one in immersive Virtual Reality (VR) and the other in mobile Augmented Reality (AR). We conducted a study with 36 participants to evaluate performance and collaboration a...
Article
The visual fidelity of realistic renderings in Computer Graphics depends fundamentally upon how we model the appearance of objects resulting from the interaction between light and matter reaching the eye. In this paper, we survey the research addressing appearance modelling of living human tissue. Among the many classes of natural materials already...
Conference Paper
Full-text available
The effectiveness of Virtual Environments (VEs) may be defined in terms of different aspects. A common one is the degree to which the VE creates in the user the subjective illusion of presence, the sense of being in the VE. Since presence is a subjective condition, it has most commonly been measured by subjective methods, especially by post-questio...
Conference Paper
Full-text available
The effectiveness of Virtual Environments (VEs) may be defined in terms of different aspects. A common one is the degree to which the VE creates in the user the subjective illusion of presence, the sense of being in the VE. Since presence is a subjective condition, it has most commonly been measured by subjective methods, especially by post-questio...
Article
Full-text available
In teleoperation, and particularly when controlling semi-autonomous robots that need to be supervised during long tasks, the user can be easily distracted losing its situational awareness. In this paper, we compare three types of alert signals: haptic, visual and auditory, to determine whats the better way to get the pre-attention of the user in cr...
Conference Paper
Full-text available
In the context of the 3DUI Contest promoted by the IEEE VR 2018, we propose 3D interaction techniques that address three distinct tasks in a virtual environment setup: climbing a ladder, controlling a quadcopter in a first-person view flight, and building a tower by stacking a series of objects. The interaction techniques were developed so the play...
Article
Phase-change phenomena are present in our daily life. Examples are the evaporation of a fluid when it reaches its boiling temperature, the condensation of water vapor in air due to the pressure changes or due to the difference of temperature in boundaries, and the melting of snow when winter is ending. Current development in physics-based animation...
Chapter
Full-text available
Veering is a common experience for blind pedestrians and for individuals walking in unfamiliar spaces. In this paper, we assess a vibrotactile Head-Mounted Display to assist blind individuals to walk straight from a point to another. Our goal was to assess such device for both assistance and self-Orientation and Mobility (O&M) training to provide m...
Chapter
Full-text available
In computer-mediated tactile intercommunication, users not only have to perceive tactile cues but also have to articulate them to carry a two-way interaction. By pressing buttons or performing specific gestures, interlocutors can exchange tactile signals but are not able to extrapolate the given vocabulary. When more access to hardware parameters i...
Conference Paper
Full-text available
We present the design of a handheld-based interface for collaborative manipulations of 3D objects in mobile augmented reality. Our approach combines touch gestures and device movements for fast and precise control of 7-DOF transformations. Moreover, the interface creates a shared medium where several users can interact through their point-of-view a...
Article
Introduction Mobile devices and software are now available with sufficient computing power, speed and complexity to allow for real-time interpretation of radiology exams. In this paper, we perform a multivariable user study that investigates concordance of image-based diagnoses provided using mobile devices on the one hand and conventional workstat...
Conference Paper
Full-text available
In radiology diagnosis, medical images are most often visualized slice by slice. At the same time, the visualization based on 3D volumetric rendering of the data is considered useful and has increased its field of application. In this work, we present a case-based study with 16 medical specialists to assess the diagnostic effectiveness of a Virtual...
Conference Paper
Full-text available
Object manipulation in 3D virtual environments demands a combined coordination of rotations, translations and scales, as well as the camera control to change the user's viewpoint. Then, for many manipulation tasks, it would be advantageous to share the interaction complexity among team members. In this paper we propose a novel 3D manipulation inter...
Article
Full-text available
Simulations of cuts on deformable bodies have been an active research subject for more than two decades. However, previous works based on finite element methods and mass spring meshes cannot scale to complex surgical scenarios. This article presents a novel method that uses position-based dynamics (PBD) for mesh-free cutting simulation. The propose...
Article
Full-text available
Due to the perceptual characteristics of the head, vibrotactile Head-mounted Displays are built with low actuator density. Therefore, vibrotactile guidance is mostly assessed by pointing towards objects in the azimuthal plane. When it comes to multisensory interaction in 3D environments, it is also important to convey information about objects in t...
Article
Full-text available
Introduction A medical application running outside the workstation environment has to deal with several constraints, such as reduced available memory and low network bandwidth. The aim of this paper is to present an approach to optimize the data flow for fast image transfer and visualization on mobile devices and remote stationary devices. Methods...
Conference Paper
Full-text available
Interaction in augmented reality environments may be very complex, depending on the degrees of freedom (DOFs) required for the task. In this work we present a 3D user interface for collaborative manipulation of virtual objects in augmented reality (AR) environments. It maps position - acquired with a camera and fiducial markers - and touchscreen in...
Article
In radiology diagnosis, medical images are most often visualized slice by slice. At the same time, the visualization based on 3D volumetric rendering of the data is considered useful and has increased its field of application. In this work, we present a case-based study with 16 medical specialists to assess the diagnostic effectiveness of a Virtual...
Conference Paper
Full-text available
With interactive maps a person can manage to find the way from one point to another, using an allocentric perspective (e.g. Google Maps), but also looking at a location as from the inside of the map with an egocentric perspective (e.g. Google Street View). Such experience cannot be performed with tactile maps, mostly explored from a top-view. To so...
Poster
In the radiology diagnosis process, medical images are most often visualized slice by slice on 2D screens or printed. At the same time, the visualization based on 3D volumetric rendering of the data is considered useful and has increased its field of application. In this work we present a user study with medical specialists to assess the diagnostic...
Article
Full-text available
While improved visual realism is known to enhance training effectiveness in virtual surgery simulators, the advances on realistic rendering for these simulators is slower than similar simulations for man-made scenes. One of the main reasons for this is that in vivo data is hard to gather and process. In this paper, we propose the analysis of videol...
Conference Paper
Computer simulation of surgical environments is always oversimplified in terms of physical behavior due to the complexity of the tissues and interactions involved, which cannot be fully simulated in real time. To better manage this trade-off between efficiency and effectiveness, we present a hybrid and adaptive environment that combines a set of me...
Article
Aplicações médicas como simuladores virtuais de cirurgia são importantes ferramentas de estudo e treinamento para a área médica. A qualidade visual das cenas virtuais beneficia o desenvolvimento de habilidades pertinentes, de acordo com o conceito de simulação PSVR (\textit{Patient Specific Virtual Reality}). Neste contexto, técnicas de representaç...
Conference Paper
Full-text available
Actuator density is an important parameter in the design of vibrotactile displays. When it comes to obstacle detection or navigation tasks, a high number of tactors may provide more information, but not necessarily better performance. Depending on the body site and vibration parameters adopted, high density can make it harder to detect tactors in a...
Presentation
Every year there’s more than 700,000 work accidents in Brazil. To address their consequences, governments and companies spend more than 30 billion dollars a year. To reduce these accidents, we propose the use of VR simulators to assess capability for safe behavior among workers. In a typical simulation session, the user wears a head-mounted display...
Presentation
Full-text available
In diagnosis, 3D image acquisition is ubiquitous (e.g. CT and MRI). Nevertheless, the outgoing images are most often visualized slice by slice on 2D screens or printed out. In some specific cases, however, it is useful to visualize a 3D volumetric rendering of the data. This is done as interactive projections on 2D conventional monitors, and allows...
Conference Paper
Researchers have investigated the tracking and recognition of human postures for a long time. Firstly, with the objective of better understanding our movements and behaviors, and then to detect wrong movements and try to help people to perform better. The equipments used to track these movements were invasive, complex and expensive, but with the re...
Chapter
Full-text available
Even if the sense of touch is fundamental in real life, few technology has implemented it efficiently in virtual reality. One of the reasons for that is the lack of knowledge on related technologies and on tactile perception. In this tutorial, we present the tools for building haptic interfaces for virtual applications. We start presenting the perc...
Conference Paper
Full-text available
Several studies evaluated vibrotactile stimuli on the head to aid orientation and communication. However, the acuity for vibration of the head's skin still needs to be explored. In this paper, we report the assessment of the spatial resolution on the head. We performed a 2AFC psychophysical experiment systematically varying the distance between pai...
Conference Paper
Full-text available
In this paper, we look upon elements present in speech articulation to introduce proactive haptic articulation as a novel approach for communication in Collaborative Virtual Environments. We defend the hypothesis that elements present in natural language, when added to the design of the vibrotactile vocabulary, should provide an expressive medium f...