Interocular conflict from a monocular augmented reality display: Impact of visual characteristics on performance.
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ABSTRACT:
SUBMITTER: Bayle E
PROVIDER: S-EPMC8412327 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Neural suppression plays an important role in cortical function, including sensory, memory, and motor systems. It remains, however, relatively poorly understood. A paradigmatic case arises when conflicting images are presented to the two eyes. These images can compete for awareness, and one is usually strongly suppressed. The mechanisms that resolve such interocular conflict remain unclear. Suppression could arise solely from "winner-take-all" competition between neurons responsive to each eye. Alternatively, suppression could also depend upon neurons detecting interocular conflict. Here, we provide physiological evidence in human visual cortex for the latter: suppression depends upon conflict-sensitive neurons. We recorded steady-state visual evoked potentials (SSVEP), and used the logic of selective adaptation. The amplitude of SSVEP responses at intermodulation frequencies strengthened as interocular conflict in the stimulus increased, suggesting the presence of neurons responsive to conflict. Critically, adaptation to conflict both reduced this SSVEP effect, and increased the amount of conflict needed to produce perceptual suppression. The simplest account of these results is that interocular-conflict-sensitive neurons exist in human cortex: adaptation likely reduced the responsiveness of these neurons which in turn raised the amount of conflict required to produce perceptual suppression. Similar mechanisms may be used to resolve other varieties of perceptual conflict.
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Project description:PurposeOnly a few studies have evaluated Augmented Reality (AR) in in vivo simulations compared to traditional laparoscopy; further research is especially needed regarding the most effective AR visualization technique. This pilot study aims to determine, under controlled conditions on a 3D-printed phantom, whether an AR laparoscope improves surgical outcomes over conventional laparoscopy without augmentation.MethodsWe selected six surgical residents at a similar level of training and had them perform a laparoscopic task. The participants repeated the experiment three times, using different 3D phantoms and visualizations: Floating AR, Occlusion AR, and without any AR visualization (Control). Surgical performance was determined using objective measurements. Subjective measures, such as task load and potential application areas, were collected with questionnaires.ResultsDifferences in operative time, total touching time, and SurgTLX scores showed no statistical significance ([Formula: see text]). However, when assessing the invasiveness of the simulated intervention, the comparison revealed a statistically significant difference ([Formula: see text]). Participants felt AR could be useful for various surgeries, especially for liver, sigmoid, and pancreatic resections (100%). Almost all participants agreed that AR could potentially lead to improved surgical parameters, such as operative time (83%), complication rate (83%), and identifying risk structures (83%).ConclusionAccording to our results, AR may have great potential in visceral surgery and based on the objective measures of the study, may improve surgeons' performance in terms of an atraumatic approach. In this pilot study, participants consistently took more time to complete the task, had more contact with the vascular tree, were significantly more invasive, and scored higher on the SurgTLX survey than with AR.
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Project description:Many salient visual events tend to coincide with auditory events, such as seeing and hearing a car pass by. Information from the visual and auditory senses can be used to create a stable percept of the stimulus. Having access to related coincident visual and auditory information can help for spatial tasks such as localization. However not all visual information has analogous auditory percepts, such as viewing a computer monitor. Here, we describe a system capable of detecting and augmenting visual salient events into localizable auditory events. The system uses a neuromorphic camera (DAVIS 240B) to detect logarithmic changes of brightness intensity in the scene, which can be interpreted as salient visual events. Participants were blindfolded and asked to use the device to detect new objects in the scene, as well as determine direction of motion for a moving visual object. Results suggest the system is robust enough to allow for the simple detection of new salient stimuli, as well accurately encoding direction of visual motion. Future successes are probable as neuromorphic devices are likely to become faster and smaller in the future, making this system much more feasible.
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Project description:BACKGROUND:Remote virtual rehabilitation aroused growing interest in the last decades, and its role has gained importance following the recent spread of COVID19 pandemic. The advantages of virtual reality (VR), augmented reality (AR), gamification, and telerehabilitation have been demonstrated in several medical fields. In this review, we searched the literature for studies using these technologies for orthopedic rehabilitation and analyzed studies' quality, type and field of rehabilitation, patients' characteristics, and outcomes to describe the state of the art of VR, AR, gamification, and telerehabilitation for orthopedic rehabilitation. METHODS:A comprehensive search on PubMed, Medline, Cochrane, CINAHL, and Embase databases was conducted. This review was performed according to PRISMA guidelines. Studies published between 2015 and 2020 about remote virtual rehabilitations for orthopedic patients were selected. The Methodological Index for Non-Randomized Studies (MINORS) and Cochrane Risk-of-Bias assessment tool were used for quality assessment. RESULTS:24 studies (9 randomized controlled trials (RCTs) and 15 non-randomized studies) and 2472 patients were included. Studies mainly concern telerehabilitation (56%), and to a lesser extent VR (28%), AR (28%), and gamification (16%). Remote virtual technologies were used following knee and hip arthroplasty. The majority of included patients were between 40 and 60 years old and had a university degree. Remote virtual rehabilitation was not inferior to face-to-face therapy, and physical improvements were demonstrated by increased clinical scores. Orthopedic virtual remote rehabilitation decreased costs related to transports, hospitalizations, and readmissions. CONCLUSION:The heterogeneity of included studies prevented a meta-analysis of their results. Age and social context influence adaptability to technology, and this can modify compliance to treatment and outcomes. A good relationship between patient and physiotherapist is essential for treatment compliance and new technologies are useful to maintain clinical interactions remotely. Remote virtual technologies allow the delivery of high-quality care at reduced costs. This is a necessity given the growing demand for orthopedic rehabilitation and increasing costs related to it. Future studies need to develop specific and objective methods to evaluate the clinical quality of new technologies and definitively demonstrate advantages of VR, AR, gamification, and telerehabilitation compared to face-to face orthopedic rehabilitation.
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Project description:A novel see-through optical device to combine the real world and the virtual image is proposed which is called an index-matched anisotropic crystal lens (IMACL). The convex lens made of anisotropic crystal is enveloped with the isotropic material having same refractive index with the extraordinary refractive index of the anisotropic crystal. This optical device functions as the transparent glass or lens according to the polarization state of the incident light. With the novel optical property, IMACL can be utilized in the see-through near eye display, or head-mounted display for augmented reality. The optical property of the proposed optical device is analyzed and aberration by the anisotropic property of the index-matched anisotropic crystal lens is described with the simulation. The concept of the head-mounted display using IMACL is introduced and various optical performances such as field of view, form factor and transmittance are analyzed. The prototype is implemented to verify the proposed system and experimental results show the mixture between the virtual image and real world scene.
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Project description:It is well known that wearing virtual reality (VR) and augmented reality (AR) devices for long periods can cause visual fatigue and motion sickness due to vergence-accommodation conflict (VAC). VAC is considered the main obstacle to the development of advanced three-dimensional VR and AR technology. In this paper, we present a novel AR high-density super-multiview (HDSMV) display technique capable of eliminating VAC in wide range. The designed binocular time-sequential AR HDSMV projection, which delivers 11 views to each eye pupil, is experimentally demonstrated, confirming that VAC is eliminated over a wide-range of viewer's focus distance. It is believed that the proposed time-sequential AR HDSMV method will pave the way for the development of VAC-free AR technology.
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