Daniel Simões Lopes

Instituto Superior Técnico · Computer Science and Engineering

Informal caregivers play an essential role in caring for persons who require assistance and in managing the health of their loved ones. Unfortunately, they need more health, leisure, and relaxation time. Nature interaction is one of many kinds of self-care intervention. It has long been regarded as a refreshing break from stressful routines, and re...

Deep inferior epigastric artery perforator (DIEAP) flap reconstruction surgeries can potentially benefit from augmented reality (AR) in the context of surgery planning and outcomes improvement. Although three-dimensional (3D) models help visualize and map the perforators, the anchorage of the models to the patient's body during surgery does not con...

Interactive real-time rigid body simulation is a crucial tool in any modern game engine or 3D authoring tool. The quest for fast, robust and accurate simulations is ever evolving. PBRBD (Position Based Rigid Body Dynamics), a recent expansion of PBD (Position Based Dynamics), is a novel approach for this issue. This work aims at providing a compreh...

To test and evaluate the second installment of DENTIFY, a virtual reality haptic simulator for Operative Dentistry (OD), on preclinical dental students, by focusing on user performance and self-assessment. Twenty voluntary unpaid preclinical dental students, with different background experience, were enrolled for this study. After the completion of...

Monitoring and analyzing physical activity is becoming an important task in both clinical and non-clinical settings. To accomplish this desideratum, stick figures are often used as abstractions of human poses and movements by representing body segments as straight lines (sticks). Despite their straightforwardness, this minimalist representation is...

Applying the correct set of Boolean operations is a fundamental task in constructive solid geometry (CSG), which is a staple in automated manufacturing systems. Although textual buttons and icons are the most common interfaces to apply such operations, these require an unnecessary cognitive load that hampers the solid modeling process. This study p...

Deep learning (DL) models are very useful for human activity recognition (HAR); these methods present better accuracy for HAR when compared to traditional, among other advantages. DL learns from unlabeled data and extracts features from raw data, as for the case of time-series acceleration. Sliding windows is a feature extraction technique. When us...

Background: Dental education and training have been centered on traditional verbal instructions and subsequent execution on training models, however these have limitations. Virtual Reality (VR) and simulators have been proposed with promising initial results and advantages and have showed promising results in the pre-clinical training environment....

The Empathy-Effective Communication hypothesis states the better a speaker can understand their listener's emotions, the better can they transmit information; and the better a listener can understand the speaker's emotions, the better can they apprehend the information. Previous emotional sharing systems have managed to create a space of emotional...

Supershapes are used in Parametric Design to model, literally, thousands of natural and man-made shapes with a single 6 parameter formula. However, users are left to probe such a rich yet dense collection of supershapes using a set of independent 1-D sliders. Some of the formula's parameters are non-linear in nature, making them particularly diffic...

Immersive colonography allows medical professionals to navigate inside the intricate tubular geometries of subject-specific 3D colon images using Virtual Reality displays. Typically, camera travel is performed via Fly-Through or Fly-Over techniques that enable semi-automatic traveling through a constrained, well-defined path at user-controlled spee...

The goal of this study is to explore the potential of the Optical See-Through Augmented Reality (OST-AR) in the training of median and paramedian epidural anaesthesia administration. To this end, we propose EpiduralLens, an epidural needle insertion simulator that augments the training space by resorting to a dummy, a HoloLens, an AR target, 3D sou...

This work presents Motion Envelopes (ME), a simple method to estimate the missing longitudinal rotations of minimal stick figures, which is based on the spatial-temporal surface traced by line segments that connect contiguous pairs of joints. We validate ME by analyzing the gait patterns of 6 healthy subjects, comprising a total of 18 gait cycles....

Human Activity Recognition (HAR) plays an important role in behavior analysis, video surveillance, gestures recognition, gait analysis, and posture recognition. Given the recent progress of Artificial Intelligence (AI) applied to HAR, the inputs that are the data from wearable sensors can be treated as time-series from which movement events can be...

We present AR-Pose, a mobile AR app to generate keyframe-based animations of rigged humanoid characters. The smartphone's positional and rotational degrees of freedom are used for two purposes: (i) as a 3D cursor to interact with inverse kinematic (IK) controllers placed on or near the character's joints; and (ii) as a virtual camera that enables u...

As the oldest medical craft, anatomy remains the core and foundational field of medicine. That is why anatomy is in perpetual advancement, thanks to the technical progress in exploring the human body through computer science and biomedical research. Knowledge of the human body is the basis of medicine. Classical cadaver dissection, the standard dis...

Computed Tomography (CT) is a commonly used imaging modality across a wide variety of diagnostic procedures (World Health Organisation 2017). By generating contiguous cross-sectional images of a body region, CT has the ability to represent valuable 3D data that enables professionals to easily identify, locate, and accurately describe anatomical lan...

3D reconstruction from anatomical slices permits anatomists to create three-dimensional depictions of real structures by tracing organs from sequences of cryosections. A wide variety of tools for 3D reconstruction from anatomical slices are becoming available for use in training and study. In this chapter, we present Anatomy Studio, a collaborative...

Virtual Reality (VR) technology enables users to immerse themselves in artificial worlds. However, it isolates users from the outside world and impedes them from collaborating with other users who might be outside of the VR experience and vice-versa. We implemented two systems where we explore how such an external user in the real world can interac...

Surface aligned splatting is a popular rendering technique to visualize reconstructed meshes and point clouds scanned from the real world. Such data typically presents some degree of noise that jeopardizes any attempt to render a perfectly smooth normal field and, more importantly, the estimated tangent vector fields are not locally continuous, thu...

Introduction Marker-based motion tracking systems are the golden standard for human motion analysis, however such systems are expensive, non-portable and require long time subject preparation. The Kinect One sensor, being inexpensive, portable and markerless, appears as a reliable and valid alternative to the marker-based systems in several situati...

Introduction It is estimated that 55% to 75% of individuals who experience a stroke have persistent impairment of the affected upper limb (UL) [1 Dobkin BH. Strategies for stroke rehabilitation. Lancet Neurol. 2004;3(9):528–536.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar],2 Kwakkel G, Kollen BJ, van der Grond J, et al. Probability of...

Introduction In recent years, we have witnessed a growing number of people needing locomotion rehabilitation (e.g. stroke). The inability to walk has tremendous effects on the individuals' wellbeing and quality of life, making locomotion rehabilitation a vital component of physiotherapy. Virtual reality (VR), a term used to describe a technological...

Introduction In clinical practice, physiotherapists often support 3–5 patients, simultaneously. They are frequently roaming throughout the room, switching between patients, taking notes, planning, demonstrating, coordinating, and monitoring multiple exercises. In such demanding environments, it is common for important events to go unnoticed. In lig...

Introduction: Innovations in 3D spatial technology and augmented reality imaging driven by digital high-tech industrial science have accelerated experimental advances in breast cancer imaging and the development of medical procedures aimed to reduce invasiveness. Presentation of case: A 57-year-old post-menopausal woman presented with screen-det...

This book offers readers fresh insights on applying Extended Reality to Digital Anatomy, a novel emerging discipline. Indeed, the way professors teach anatomy in classrooms is changing rapidly as novel technology-based approaches become ever more accessible. Recent studies show that Virtual (VR), Augmented (AR), and Mixed-Reality (MR) can improve b...

Background Tools for training and education of dental students can improve their ability to perform technical procedures such as dental implant placement. Shortage of training can negatively affect dental implantologists’ performance during intraoperative procedures, resulting in lack of surgical precision and, consequently, inadequate implant plac...

Immersive Colonography allows medical professionals to navigate inside the intricate tubular geometries of subject-specific 3D colon images using Virtual Reality displays. Typically, camera travel is performed via Fly-Through or Fly-Over techniques that enable semi-automatic traveling through a constrained, well-defined path at user controlled spee...

Introduction: Frequently used as an abstract representation of the human body, stick figure models acquired from markerless MOCAP systems do not allow to properly estimate the internal rotation of body segments. Since, each "stick" is usually defined by only 2 points, stick figures do not provide enough information to compute all 6 degrees-of-freed...

Recent research has been using automatic difficulty adjustment techniques as an effective channel to improve the quality of physical rehabilitation. Notably, these approaches often incorporate adaptation metrics such as emotions and performance. Nonetheless, compensatory movements, which hinder movement correctness and are considered as a core qual...

Conventional needle insertion training relies on medical dummies that simulate surface anatomy and internal structures such as veins or arteries. These dummies offer an interesting space to augment with useful information to assist training practices, namely, internal anatomical structures (subclavian artery and vein, internal jugular vein and caro...

Understanding the morphological features characterizing a normal femoral head and acetabular cavity is critical for a more comprehensive and updated definition of hip anatomy. Based on anatomical observations, MacConaill introduced the notion that spheroidal articular surfaces are better represented by ovoidal shapes, in comparison with the still v...

Face-to-face telepresence promotes the sense of ”being there” and can improve collaboration by allowing immediate understanding of remote people’s nonverbal cues. Several approaches successfully explored interactions with 2D content using a see-through whiteboard metaphor. However, with 3D content, there is a decrease in awareness due to ambiguitie...

Foot input has been proposed to support hand gestures in many interactive contexts, however, little attention has been given con-tactless 3D object manipulation. This is important since many applications , namely sterile surgical theaters require contactless operation. However, relying solely on hand gestures makes it difficult to specify precise i...

Face-to-face telepresence promotes the sense of "being there" and can improve collaboration by allowing immediate understanding of remote people's nonverbal cues. Several approaches successfully explored interactions with 2D content using a see-through whiteboard metaphor. However, with 3D content, there is a decrease in awareness due to ambiguitie...

3D reconstruction from anatomical slices allows anatomists to create three dimensional depictions of real structures by tracing organs from sequences of cryosections. However, conventional user interfaces rely on single-user experiences and mouse-based input to create content for education or training purposes. In this work, we present Anatomy Stud...

Feet input can support mid-air hand gestures for touchless medical image manipulation to prevent unintended activations, especially in sterile contexts. However, foot interaction has yet to be investigated in dental settings. In this paper, we conducted a mixed methods research study with medical dentistry professionals. To this end, we developed a...

In this preliminary study, we propose visual biofeedback techniques for representing compensatory movements that are commonly found in upper limb rehabilitation exercises. Here, visual biofeedback is represented by stick figures adorned with different graphical elements to highlight abnormal motor patterns. We explore 4 visual biofeedback technique...

Introduction: The growing interest of Augmented Reality (AR) together with the renaissance of Virtual Reality (VR) opened new possibilities to redesign how professionals interact with medical images. Several medical specialties already rely on 2D and 3D image data for diagnosis, surgical planning, surgical navigation, medical education and patient-...

Introduction: Most medical specialties rely on 3D image data either for diagnosis, surgical planning, surgical navigation, education or patient-clinician communication. Surprisingly, conventional medical image workstations do not promote proper visual insight nor visual collaboration between professionals. Redesigning conventional applications into...

Despite its marked success in recent years, it is still not clear how Virtual Reality (VR) can assist architects at the early stages of ideation and design. In this paper, we approach VR to build and explore maquettes at different scales in early design stages. To this end we developed a VR environment where user interactions are supported by untet...

Visual quality of volume rendering for medical imagery strongly depends on the underlying transfer function. Conventional Windows–Icons–Menus–Pointer interfaces typically refer the user to browse a lengthy catalog of predefined transfer functions or to pain-staking refine the transfer function by clicking and dragging several independent handles. T...

In molecular biology, protein docking aims at finding the conformation in which two proteins are attached together in their native state. Several software approaches for docking already exist, which still rely on conventional interaction techniques , and have not yet taken advantage of the immersiveness nor expeditiousness made available by the new...

Current state-of-the-art point cloud visualization techniques have shortcomings when dealing with sparse and less accurate data or close-up interactions. In this paper, we present a visualization technique called stroke-based splatting, which applies concepts of stroke-based rendering to surface-aligned splatting, allowing for better shape percepti...

Vital signs monitoring is pivotal not only in clinical settings but also in home environments. Remote monitoring devices, systems, and services are emerging as tracking vital signs must be performed on a daily basis. Different types of sensors can be used to monitor breathing patterns and respiratory rate. However, the latter remains the least meas...

CT Colonography (CTC) is considered the leading imaging technique for colorectal cancer (CRC) screening. However, conventional CTC systems rely on clumsy 2D input devices and stationary flat displays that make it hard to perceive the colon structure in 3D. To visualize such anatomically complex data, the immersion and freedom of movement afforded b...

Computed Tomography Colonography (CTC) is an established non-invasive colorectal screening tool that can replace traditional colonoscopy [1, 2]. As an image-based procedure, CTC 3D reconstruction pipeline requires a CT acquisition after intestinal preparation, namely in supine or prone position. Afterwards, a sequence of image processing and mesh a...

REngine consists of a complete Unity (C#) project for interactive volume rendering of 3D Textures and surface rendering of triangular meshes. Volume data is reconstructed from medical image datasets, such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), and rendered using a raymarching shader. Surface renderings are created based on...

Understanding morphological features that characterize normal hip joint is critical and necessary for a more comprehensive definition of pathological presentations, such as femoroacetabular impingement and hip dysplasia. Based on anatomical observations that articular surfaces of synovial joints are better represented by ovoidal shapes than by sphe...

Navigating 3-D parameter domains, such as color and orientation of an object, is a common task performed in most computer graphics applications. Although 1-D sliders are the most common interface for browsing such domains, they provide a tedious and difficult user experience that hampers finding desirable visual solutions. We present the Rhomb-i sl...

10.21820/23987073.2017.10.76

Reading-room conditions such as illumination, ambient light, and display luminance play an important role in how radiologists analyze and interpret images. Indeed, serious diagnostic errors can appear when observing images through everyday monitors. Typically these occur whenever professionals are ill positioned with respect to the display, or when...

Physicians take advantage of desktop and mobile software to perform their work, although current visualization systems still rely on interaction approaches that do not go beyond 2D interfaces. The advent of portable devices, such as tablets, coupled with the growing need to explore and apply 3D image manipulation techniques, motivated our team to d...