Helmet Mounted Display Layouts

Recupera algunos de los elementos menos estudiados y reconocidos en el ensayo latinoamericano: su profunda vocación de reflexión, diálogo y mediación intelectual; su plasticidad y apertura a la búsqueda del sentido; su vínculo con la sociabilidad, la conversación y la generación de un espacio simbólico de encuentro; su capa cidad de establecer una nueva retroalimentación entre lectura y escritura.

During the last few years head mounted displays (HMD) became more important in Computer assisted surgery (CAS). Rapid head movements of the surgeon enforce to change the focal plane and the zoom value without loosing the calibration. Starting from previous work in developing an optical see through head mounted display we adapted our HMD to measure the focal and zoom values. This made it possible to extend the calibration to different zoom and focus values. The case of the HMD was opened to gain access to the zoom lenses, which was necessary to measure the different zoom values. Focusing in our HMD is realized by changing the angle between the two tubes. Therefore we marked two points at the tubes to measure the focal adjustment. We made a series of planar calibrations with seven different fixed zoom and focus values using Tsai´s algorithm for camera calibration. Then we used the Polaris optical tracking system (Northern Digital, Ontario, Can) to measure the transformation from the planar calibration grid to a tracker probe rigidly mounted to the HMD. The calibration parameters transformed to this tracker probe are independent of the actual position of the calibration grid andare the parameters we want to approximate. Then least square approximating polynomial surfaces were derived for the seven calibration parameters. The coefficients of the polynomial surfaces were used as starting values for a nonlinear optimization procedure minimizing an overall error. Minimizing the object space error (which is the minimal distance of the line through the center of projection and the image point to the real world point) in the last step of the procedure described above we had a mean object space error 0.85 ±0.5 mm. Calibration of the HMD is not lost during minor changes in zoom and focus. This is likely to be the first optical see through HMD developed for CAS with variable zoom and focus, which are typically facilities of operating microscopes. Employing an automated calibration in common with more zoom and focus steps and more accurate measurement of the position of the zoom lenses and the focal plane should reduce the error significantly, enabling the accuracy needed for CAS.

Extended-Reality Technologies: An Overview of Emerging Applications in Medical Education and Clinical Care.

Inherent to the field of computer-aided surgery (CAS) is the necessity to handle sophisticated equipment in the operating room; an undesired side-effect of this development is the fact that the surgeon’s attention is drawn from the operating field since surgical progress is partially monitored on the computer’s screen. The overlay of computer-generated graphics over a real-world scene, also referred to as augmented reality (AR), provides a possibility to solve this problem. The considerable technical problems associated with this approach such as viewing of the scenery within a common focal range on the head-mounted display (HMD) or latency in display on the HMD have, however, kept AR from widespread usage in CAS. In this paper, the concept of the Varioscope AR, a lightweight head-mounted operating microscope used as a HMD, is introduced. The registration of the patient to the preoperative image data as well as preoperative planning take place on VISIT, a surgical navigation system developed at our hospital. Tracking of the HMD and stereoscopic visualisation take place on a separate POSIX.4 compliant realtime operating system running on PC hardware. While being in a very early stage of laboratory testing, we were able to overcome the technical problems described above; our work resulted in an AR visualisation system with an update rate of 6 Hz and a latency below 130 ms. First tests with 2D/3D registration have shown a match between 3D world coordinates and 2D HMD display coordinates in the range of 1.7 pixels. It integrates seamlessly into a surgical navigation system and provides a common focus for both virtual and real world objects. On the basis of our current results, we conclude that the Varioscope AR with the realtime visualisation unit is a major step towards the introduction of AR into clinical routine.

In this paper, we consider a virtual tennis as an application of virtual reality. In such an application, not only a visual display but also a force display is an important device. This device should have its large feasible area, high speed, high acceleration, force presentation to an operator and safety simultaneously. Then, we propose a new type force display system using a parallel wire drive mechanism. Because this force display has some advantages of its low inertia and simple structure, its good performance is expected. In this paper, we firstly specify details of the virtual tennis system, including an HMD (Head Mounted Display). Secondly, we describe a new method to investigate the feasible area of the proposed force display. Also, an easy procedure of calculating desired wire tension is proposed. Finally, we demonstrate some basic experimental results to verify performance of the proposed display.

Purpose Evacuation drills should be more realistic and interactive. Focusing on situational and audio-visual realities and scenario-based interactivity, the authors have developed a game-based evacuation drill (GBED) system that presents augmented reality (AR) materials on tablet computers. The paper's current research purpose is to improve visual reality (AR materials) in our GBED system. Design/methodology/approach The author's approach is to develop a new GBED system that superimposes digital objects [e.g. three-dimensional computer graphics (3DCG) elements] onto real-time vision using a marker-based AR library, a binocular opaque head-mounted display (HMD) and other current easily available technologies. Findings The findings from a trial experiment are that the new GBED system can improve visual reality and is appropriate for disaster education. However, a few problems remain for practical use. Research limitations/implications When using the GBED system, participants (i.e. HMD wearers) can suffer from 3D sickness and have difficulty in moving. These are important safety problems in HMD-based systems. Social implications The combination of AR and HMDs for GBEDs (i.e. integrating virtual and real worlds) will raise questions about its merits (pros and cons). Originality/value The originality of the research is the combination of AR and an HMD to a GBED, which has previously been realized primarily as simulation games in virtual worlds. The authors believe that our research has the potential to expand disaster education.

Computer-aided surgery (CAS), the intraoperative application of biomedical visualization techniques, appears to be one of the most promising fields of application for augmented reality (AR), the display of additional computer-generated graphics over a real-world scene. Typically a device such as a head-mounted display (HMD) is used for AR. However, considerable technical problems connected with AR have limited the intraoperative application of HMDs up to now. One of the difficulties in using HMDs is the requirement for a common optical focal plane for both the realworld scene and the computer-generated image, and acceptance of the HMD by the user in a surgical environment. In order to increase the clinical acceptance of AR, we have adapted the Varioscope (Life Optics, Vienna), a miniature, cost-effective head-mounted operating binocular, for AR. In this paper, we present the basic design of the modified HMD, and the method and results of an extensive laboratory study for photogrammetric calibration of the Varioscope's computer displays to a real-world scene. In a series of 16 calibrations with varying zoom factors and object distances, mean calibration error was found to be 1.24 +/- 0.38 pixels or 0.12 +/- 0.05 mm for a 640 x 480 display. Maximum error accounted for 3.33 +/- 1.04 pixels or 0.33 +/- 0.12 mm. The location of a position measurement probe of an optical tracking system was transformed to the display with an error of less than 1 mm in the real world in 56% of all cases. For the remaining cases, error was below 2 mm. We conclude that the accuracy achieved in our experiments is sufficient for a wide range of CAS applications.

INTRODUCTION: When we move through the environment, the self-to-surround relations constantly change. Nevertheless, we perceive the world as stable. A process that is critical to this perceived stability is "spatial updating", which automatically updates our egocentric mental spatial representation of the surround according to our current self-motion. According to the prevailing opinion, vestibular and proprioceptive cues are absolutely required for spatial updating. Here, we challenge this notion by varying visual and vestibular contributions independently in a high-fidelity VR setup. METHODS: In a learning phase, participants learned the positions of twelve targets attached to the walls of a 5x5m room. In the testing phase, participants saw either the real room or a photo-realistic copy presented via a head-mounted display (HMD). Vestibular cues were applied using a motion platform. Participants' task was to point "as accurately and quickly as possible" to four targets announced consecutively via headphones after rotations around the vertical axis into different positions. RESULTS: Automatic spatial updating was observed whenever useful visual information was available: Paticipants had no problem mentally updating their orientation in space, irrespective of turning angle. Performance, quantified as response time, configuration error, and pointing error, was best in the real world condition. However, when the field of view was limited via cardboard blinders to match that of the HMD (40 × 30°), performance decreased and was comparable to the HMD condition. Presenting turning information only visually (through the HMD) hardly altered those results. In both the real world and HMD conditions, spatial updating was obligatory in the sense that it was significantly more difficult to ignore ego-turns (i.e., "point as if not having turned") than to update them as usual. CONCLUSION: The rapid pointing paradigm proved to be a useful tool for quantifying spatial updating. We conclude that, at least for the limited turning angles used (<60°), the Virtual Reality simulation of ego-rotation was as effective and convincing (i.e., hard to ignore) as its real world counterpart, even when only visual information was presented. This has relevant implications for the design of motion simulators for, e.g., architecture walkthroughs.

We aim to develop a brain-machine interface (BMI) system that estimates user's gaze or attention on an object to pick it up in the real world. In Experiment 1 and 2 we measured steady-state visual evoked potential (SSVEP) using luminance and/or contrast modulated flickers of photographic scenes presented on a head-mounted display (HMD). We applied multiclass SVM to estimate gaze locations for every 2s time-window data, and obtained significantly good classifications of gaze locations with the leave-one-session-out cross validation. In Experiment 3 we measured SSVEP using luminance and contrast modulated flickers of real scenes that were online captured by a USB camera and presented on the HMD. We put AR markers on real objects and made their locations flickering on HMD. We obtained the best performance of gaze classification with highest luminance and contrast modulation (73–91% accuracy at chance level 33%), and significantly good classification with low (25% of the highest) luminance and contrast modulation (42–50% accuracy). These results suggest that the luminance-modulated flickers of real scenes through USB camera can be applied to BMI by using augmented reality technology.

We describe an augmented reality conferencing system which uses the overlay of virtual images on the real world. Remote collaborators are represented on virtual monitors which can be freely positioned about a user in space. Users can collaboratively view and interact with virtual objects using a shared virtual whiteboard. This is possible through precise virtual image registration using fast and accurate computer vision techniques and head mounted display (HMD) calibration. We propose a method for tracking fiducial markers and a calibration method for optical see-through HMD based on the marker tracking.

Head mounted displays (HMD) provide one means of displaying virtual environments. This paper assesses the state of HMD technology, with respect to the Virtual Reality (VR) goal of creating an environment which matches user's experience with the real world. We find that current HMDs fall short in important characteristics, such as resolution, field of view, and physical attributes. A system designer, familiar with these limitations, should be able to provide a suitable immersive virtual environment with the inclusion of appropriate graphics rendering techniques and virtual environment input/output devices.

This paper describes a portable High Dynamic Range (HDR) imaging system for visually impaired people, intended to display contrast enhanced images of real world environment. The device is composed of a digital camera and head mounted display (HMD) equipped with high resolution screens. The camera is mounted on the HMD to acquire the ambient scene, the acquired images are processed to generate HDR images through the control of local luminance information. The contrast enhancement method adopted in our system is based on pyramidal image contrast structure representation that relies on the local band-limited contrast definition. The imaging system we propose aims at displaying images that meet the visual capabilities related to contrast sensitivity of people with low vision. It also provides a solution to alleviate discomfort problem expressed by these people when they are facing real-world changing light conditions.

Information management is an inseparable part of the command process. The result is that the person making decisions at the command post interacts with data providing devices in various ways. Tools virtualization process can introduce a number of significant modifications in the design of solutions for management and command. The general idea involves replacing physical devices user interface with their digital representation (so-called Virtual instruments). A more advanced level of the systems “digitalization” is to use the mixed reality environments. In solutions using Augmented reality (AR) customized HMI is displayed to the operator when he approaches to each device. Identification of device is done by image recognition of photo codes. Visualization is achieved by (optical) see-through head mounted display (HMD). Control can be done for example by means of a handheld touch panel. Using the immersive virtual environment, the command center can be digitally reconstructed. Workstation requires only VR system (HMD) and access to information network. Operator can interact with devices in such a way as it would perform in real world (for example with the virtual hands). Because of their procedures (an analysis of central vision, eye tracking) MR systems offers another useful feature of reducing requirements for system data throughput. Due to the fact that at the moment we focus on the single device. Experiments carried out using Moverio BT-200 and SteamVR systems and the results of experimental application testing clearly indicate the ability to create a fully functional information system with the use of mixed reality technology.

In this article, we present a client/server augmented reality (AR) system for viewing complex assembly models on mobile phones. Complex model information is located on a PC which takes care of all of the heavy AR tracking and rendering computation. A camera phone is used as a client to show this information, augmented on still images as animated view. The mobile phone interface also supports correct masking of the assembly pieces as they come together, as well as a graphics only viewing mode intended for better understanding of the assembly process. In addition to describing the mobile augmented assembly system we present results from two pilot user studies evaluating elements of the user interface. INTRODUCTION In order to remain competitive, today’s industry is employing a growing number of product variations with shorter and shorter life cycles, requiring efficient ways to handle the production planning and processing. Assembly line workers face more and more complex tasks and an increasing memory load is posed by the new production needs. Experienced workers may be able to handle several product variants at the same time, but new workers require training and guidance to handle the work tasks. Related activities such as maintenance and repair also require a lot of know-how of complex products. Guidance in assembly tasks is commonly provided by using printed blueprints or other documents. However, these are mainly two dimensional images or text while the real assembly task is three dimensional, making the relationship between parts hard to understand. Computer based technologies have been developed such as electronic guides, multimedia training material and interactive documents. However, these typically require the user to turn away from the assembly task to study a computer screen separate from the workspace. In our research we explore how augmented reality (AR) technology can be used to provide more intuitive guides to assist with assembly, repair and training tasks. With AR technology, synthetic objects can be merged with the user’s view of the real world so that the user can perform the assembly task without needing to look at a separate screen. The virtual objects appear in the correct position so that AR enables the creation of realistic looking 3D animated assembly “manuals”. Other researchers have developed prototype AR systems for supporting assembly tasks. These are typically based on head mounted displays (HMDs) connected to desktop or wearable computers. However, wearable computers are relatively expensive, they have a short battery life, and taking them into a harsh industrial environment is not always possible. Head mounted displays can also be bulky, they involve safety issues, and many workers are reluctant to wear them. To overcome these disadvantages, we are interested in developing a reliable mobile phone based AR assembly system. Today’s mobile phones have fast processors, significant memory, 3D graphics support, and high resolution displays. They contain various accessories that can be used for developing mobile AR applications such as good quality cameras, connectivity by Bluetooth, WLAN and GPRS, and various SAM.700.003.1155

We developed a virtual environment (VE) and artificial intelligence (AI) techniques that enables the study of virtual reality (VR) training applications to develop a sense of empathy and empathetic curiosity in nursing students towards patients living with schizophrenia. The VE is a simulated city-street setting providing simulated auditory hallucinations (hearing voices), and interactive animated non-player characters (NPCs). The VE is implemented in the Unity game development platform and is experienced using an OculusRift_S head mounted display (HMD). Our new machine learning (ML) algorithms and deep learning (DL) models provide a simulated vision capability, enabling the primary NPC to recognize the user’s facial expressions and react with a variety of facial, body, and verbal animated responses. Our ML and DL techniques are designed to provide effective facial detection and expression classification when the user’s face is occluded by the HMD. The integration of the VE and AI-based techniques provides the opportunity to create more complex, two-way user-to-NPC interactions in the future. We hypothesize that these enriched interactions provide value by simulating encounters between caregivers and patients when the same experiences are not readily available in a real world clinical environment, thus filling a need for improved empathy training. An IRB study to test our hypothesis is planned by the College of Nursing faculty.