Virtual Test Research Articles

Effect of immersive virtual reality-based cognitive remediation in patients with mood or psychosis spectrum disorders: study protocol for a randomized, controlled, double-blinded trial

BackgroundCognitive impairments are prevalent across mood disorders and psychosis spectrum disorders, but there is a lack of real-life-like cognitive training programmes. Fully immersive virtual reality has the potential to ensure motivating and engaging cognitive training directly relevant to patients’ daily lives. We will examine the effect of a 4-week, intensive virtual reality-based cognitive remediation programme involving daily life challenges on cognition and daily life functioning in patients with mood disorders or psychosis spectrum disorders and explore the neuronal underpinnings of potential treatment efficacy.MethodsThe trial has a randomized, controlled, double-blinded, parallel-group design. We will include 66 symptomatically stable outpatients with mood disorders or psychosis spectrum disorders aged 18–55 years with objective and subjective cognitive impairment. Assessments encompassing a virtual reality test of daily life cognitive skills, neuropsychological testing, measures of daily life functioning, symptom ratings, questionnaires on subjective cognitive complaints, and quality of life are carried out at baseline, after the end of 4 weeks of treatment and at a 3-month follow-up after treatment completion. Functional magnetic resonance imaging scans are performed at baseline and at the end of treatment. The primary outcome is a broad cognitive composite score comprising five subtasks on a novel ecologically valid virtual reality test of daily life cognitive functions. Two complete data sets for 54 patients will provide a power of 80% to detect a clinically relevant between-group difference in the primary outcome. Behavioural data will be analysed using linear mixed models in SPSS, while MRI data will be analysed with the FMRIB Expert Analysis Tool (FEAT). Treatment-related changes in neural activity from baseline to end of treatment will be investigated for the dorsal prefrontal cortex and hippocampus as the regions of interest.DiscussionThe results will provide insight into whether virtual reality-based cognitive remediation has beneficial effects on cognition and functioning in symptomatically stable patients with mood disorders or psychosis spectrum disorders, which can aid future treatment development.Trial registrationClinicalTrials.gov NCT06038955. Registered on September 15, 2023.

Telematics and diagnosis system for autonomous cargo vehicle

The article deals with the problem of managing the operation and maintenance of autonomous trucks KAMAZ using a telematics and diagnostics system. The functions and composition of the onboard module of a robotic vehicle are described. The main controlled values are determined. The presence of a developed system for monitoring the state of units and assemblies provides a solution to the problem of controlling the modes of the car operation. The structure of the telematics and diagnostics system has been developed and implemented. The main blocks of the proposed system are shown. The main diagnostic and forecasting functions are performed on a workstation with an analytical module. It is proposed to use an approach based on previous conditions matrixes. An example of matrix analysis for a car engine cooling system is given. Modeling of the engine cooling system was carried out and graphs of transient processes were obtained. The analytical module is designed using artificial neural networks to analyze time series of car parameter values. To conduct virtual tests of a car in various operating modes, a simulation model was developed on a stochastic time colored Petri net. The model simulates both the movement of the vehicle to the point of production operations and the change in the technical condition of the car. The model makes it possible to describe and study the influence of random factors on the time of execution of production tasks, to take into account the probabilistic characteristics of failure events or defects in vehicle components and assemblies. The use of an artificial neural network in the analytical module of the diagnostic system workstation makes it possible to predict the technical condition of vehicle components and systems in real time, followed by verification of the dynamics of processes on a simulation model on a Petri net.

Calibration of Simulation Parameters for Fresh Tea Leaves Based on the Discrete Element Method

To address the problem of a lack of accurate parameters in the discrete element simulation study of the machine-picked fresh tea leaf mechanized-sorting process, this study used machine-picked fresh tea leaves as the research object, established discrete element models of different fresh tea leaf components in EDEM software version 7.0.0. based on the bonded particle model using three-dimensional scanning inverse-modeling technology, and calibrated the simulation parameters through physical tests and virtual simulation tests. Firstly, the intrinsic parameters of machine-picked tea leaves were measured using physical tests; the physical-stacking tea leaf test was conducted using the cylinder lifting method, the tea leaf repose angle being 32.62° as measured from the stacking images using CAD. With the physical repose angle as the target value, the Plackeet–Burman test, the steepest-ascent test and the Box–Behnken optimization test were conducted in turn, and the results showed that the static friction coefficient between tea leaves, the rolling friction coefficient between tea leaves and the static friction coefficient between tea leaves and PVC have a major effect on the repose angle, and the optimal combination of the three significant parameters was determined. Finally, five simulations were conducted using the optimal combination of parameters, the relative error between the repose angle measured by the simulation test and the physical repose angle being just 0.28%. Moreover, the t-test obtained p > 0.05, indicating that there was no significant difference between the simulation test results and the physical test results. The results showed that the calibrated discrete element simulation parameters obtained could provide a reference for the discrete element simulation study of fresh tea leaves.

Material extrusion of SEEPS blended isotactic PP for possible application as automotive bumper: Performance analysis through Finite Element Simulation

3D processing of isotactic polypropylene or PP based composites through material extrusion is evolving globally as an advanced product development tool for highly specialized sectors like aerospace, biomedicals and automobiles. Conversely, pristine PP shows a severe drawback of exhibiting higher warping compared to other thermoplastics following higher crystalline shrinkage. These have prohibited the wider acceptance of virgin PP in 3D processing for product development. The current investigation is primarily aimed to overcome these disadvantages through mixing with amorphous Poly (styrene-co-(ethylene-co-(ethylene-co-propylene)-co-styrene)) or SEEPS in various mass percentages starting from 10 wt% to 30 wt% in melt before printing. The target was to make a tougher PP with retention of its original strength by reducing the shrinkage; In addition, it is also aimed to predict the usability of such material by virtual testing as a potential alternative to pristine PP for constructing an automotive bumper, designed using an AutoCAD. The printed product (dumbbell) demonstrated a higher toughness and resistance to shrinkage than pristine PP but the tensile strength and modulus decreased significantly beyond 10 wt% loading of SEEPS. Parallelly, at 10 wt% loading, the tensile strength and toughness of the printed products were found to be superior than the compression molded sample. In addition, the printed sample at this loading also possessed lower specific heat (4.79 J/g °C) than the pristine one (5.83 J/g °C) and was more thermally stable (lower degradation rate) than both the pristine and the corresponding higher blend compositions. Due to partial similarity in chemical structure between SEEPS and PP, the former had produced autonomic compatibilization with PP and formed a partially miscible blend. A car bumper was designed from this blend composition (10 wt%) using AutoCAD and its resistances to withstand against the collision stress at high (60 km/h) and low (45 km/h) car speeds were evaluated and compared virtually through Finite Element Simulation (FES) with virgin PP. Due to advantageous properties like retention of tensile strength, higher toughness and thermal stability and lower specific heat, the 10 wt% composition exhibited lesser tendency towards failure by predicting higher deformation than virgin PP. Thus it was found suitable as a bumper material which can be prototyped/finally prepared using materials extrusion technique.

Advancing ecological validity and clinical utility in virtual reality-based continuous performance test: exploring the effects of task difficulty and environmental distractors.

Researchers have highlighted concerns regarding the limited diagnostic utility and ecological validity of the Continuous Performance Test (CPT). Recent advancements in VR-based CPTs have attempted to address these concerns by simulating real-life scenarios and enhancing attention deficit hyperactivity disorder (ADHD) diagnosis; however, certain areas require improvement for obtaining reliable data from both healthy individuals and those with ADHD. To tackle these issues, we developed an enhanced VR-based CPT program featuring four distinct difficulty levels, advancing toward home-based assessment. Our feasibility study involved subjects without ADHD to establish a normative profile for VR-based CPT before extending it to ADHD assessment. Our sample included 20 Korean adults. They received a VR device with the VR-based CPT program installed and were asked to perform 1-2 blocks per day at home. Participants were instructed to complete 12 blocks over the subsequent 2 weeks. Psychological assessments and electroencephalograms (EEGs) were administered before and after the program. Post-study usability measures were also collected. Higher commission errors were notably evident in the "very high" difficulty level which featured complex stimuli and increased distraction. A notable correlation emerged between the overall distraction level and CPT accuracy, along with a significant link between intensity scores and commission errors. No significant differences were found in psychological assessment and there were no significant changes in the Theta-Beta Ratio (TBR) index before and after the program. The usability of our program was fair. The study reveals that the newly designed VR-CPT program, simulating diverse real-life environments and offering varying task difficulty levels, proved acceptable and feasible. The key point of our study was that the adjustment and segmentation of difficulty levels in the VR-based CPT were achieved, and that this effort was validated by examining the impact of different levels of difficulty on CPT measures. Implementing this experimental setup in a home-based environment increased ecological validity, as well as clinical utility. Limitations and suggested directions for further investigation are described in detail.

Nonlinear vibration characteristics of virtual mass systems for wind turbine blade fatigue testing

Abstract. The biaxial fatigue test of wind turbine blades is helpful to shorten the test time and is more suitable for the actual operating conditions. Adding tuning masses to the blade is a common method for blade uniaxial testing at present, and its purpose is to adjust the load distribution in one direction of the blade. However, the tuning masses on the blade will affect the load distribution in the direction of the blade flap-wise and edge-wise at the same time in the biaxial test, so the concept of “virtual masses” is proposed to realize the decoupling of the load distribution in the biaxial test. Due to the limitation of the size of the virtual mass mechanism and the complex motion trajectory of the blade, the actual inertial effect provided by the virtual masses is different from the ideal situation, which will affect the resonance characteristics of the test system and the load distribution of the blade. Therefore, in order to evaluate the effect of the nonlinear effect introduced by the virtual masses on the resonance characteristics of the test system and the blade load distribution, the equivalent dynamic model of the bladed virtual mass test system was established by using the Lagrange method. Then, the nonlinear effects of blade amplitude and virtual mass installation parameters on the test system are obtained by a numerical method. Then, based on the nonlinear vibration theory, the approximate nonlinear amplitude–frequency characteristics of the test system are obtained, that is, the resonance frequency of the test system will decrease with the increase in the blade amplitude. Through the simulation analysis of two blades over 80 m in length, the applicability of the theoretical method is verified. It can be seen from the simulation results of the simulated uniaxial test that larger amplitudes of the blade and shorter connection rods will reduce the resonance frequency of the test system. When the vibration amplitude at the excitation point is the same, a lower resonance frequency results in a smaller load distribution level, that is, the area which is actually fully tested will be reduced. In the biaxial simulation test, the resonance frequency of the test system will be further reduced because the virtual masses will be affected by the coupled motion in both directions at the same time. Furthermore, the introduction of an external mechanism of the virtual mass will also cause deformation of the envelope of the blade biaxial trajectory, which will further affect the load distribution of the blade. This work explores the nonlinear influence of virtual masses on the actual fatigue test. The theoretical analysis is helpful to provide the basis and reference for the preliminary preparation work of the test organization, including adjusting the tuning mass scheme, adjusting the load distribution and selecting the appropriate excitation equipment.

Feasibility evaluation of radiotherapy positioning system guided by augmented reality and point cloud registration.

To develop a radiotherapy positioning system based on Point Cloud Registration (PCR) and Augmented Reality (AR), and to verify its feasibility. The optimal steps of PCR were investigated, and virtual positioning experiments were designed to evaluate its accuracy and speed. AR was implemented by Unity 3D and Vuforia for initial position correction, and PCR for precision registration, to achieve the proposed radiotherapy positioning system. Feasibility of the proposed system was evaluated through phantom positioning tests as well as real human positioning tests. Real human tests involved breath-holding positioning and free-breathing positioning tests. Evaluation metrics included 6 Degree of Freedom (DOF) deviations and Distance (D) errors. Additionally, the interaction between CBCT and the proposed system was envisaged through CBCT and optical cross-source PCR. Point-to-plane iterative Closest Point (ICP), statistical filtering, uniform down-sampling, and optimal sampling ratio were determined for PCR procedure. In virtual positioning tests, a single registration took only 0.111 s, and the average D error for 15 patients was 0.015±0.029mm., Errors of phantom tests were at the sub-millimeter level, with an average D error of 0.6±0.2mm. In the real human positioning tests, the average accuracy of breath-holding positioning was still at the sub-millimeter level, where the errors of X, Y and Z axes were 0.59±0.12mm, 0.54±0.12mm, and 0.52±0.09mm, and the average D error was 0.96±0.22mm. In the free-breathing positioning, the average errors in X, Y, and Z axes were still less than 1mm. Although the mean D error was 1.93±0.36mm, it still falls within a clinically acceptable error margin. The AR and PCR-guided radiotherapy positioning system enables markerless, radiation-free and high-accuracy positioning, which is feasible in real-world scenarios.

Clinical report: Virtual reality enables comparable contrast sensitivity measurements to in-office testing (pilot study).

Vision health disparities largely stem from inaccessibility to vision specialists. To improve patient access to vision tests and to expedite clinical workflows, it is important to assess the viability of virtual reality (VR) as a modality for evaluating contrast sensitivity. This study aimed to assess the validity of a VR version of the Pelli-Robson contrast sensitivity test by comparing its results with those of the corresponding in-office test. Twenty-eight participants (mean ± standard deviation age, 37.3 ± 20.5 years) with corrected vision were recruited for testing on a voluntary basis with randomized administration of the in-office test followed by the VR analog or vice versa. Nineteen participants took each test twice to assess test-retest consistency in each modality. Virtual reality tests were conducted on a commercial Pico Neo Eye 2 VR headset, which has a 4K screen resolution. The environment for both tests was controlled by the participant for location and lighting. Similar sensitivity scores were obtained between testing modalities in both the right (n = 28 participants; Wilcoxon match-paired signed rank [SR], p=0.7) and left eyes (n = 28 participants; Wilcoxon match-paired SR, p=0.7). In addition, similar test-retest scores were found for VR (n = 19 participants; Wilcoxon match-paired SR, p=1.0) or in-office (n = 19 participants; Wilcoxon match-paired SR, p=1.0) tests. Virtual reality Pelli-Robson results correlated well with in-office test results in variably diseased participants (n = 14 eyes from 7 participants, R2 = 0.93, p<0.0001). In this pilot trial, we demonstrated that VR Pelli-Robson measurements of corrected vision align with those of in-office modalities, suggesting that this may be a reliable method of implementing this test in a more interactive and accessible manner.

Divergent thinking and Executive functions in children: A developmental perspective based on intellectual capacity

Despite the importance of Executive functions, Divergent thinking, and intelligence in 21st century society, few studies have analyzed these variables in childhood and adolescence. The present study aimed to examine whether Executive functions and Divergent thinking have a developmental perspective and whether these variables predict intelligence. A non-clinical sample of 159 adolescents (78 girls and 81 boys) between 12 and 16 years of age (M=13.29 years; SD=1.17) participated in the study. Three tests were administered: (1) the Ice cream Virtual Reality Test to measure Executive functions; (2) the PIC-J to evaluate Divergent thinking; and (3) the WISC-V to measure cognitive variables. Executive functions were found to be developmental, as was verbal fluency as a creative component. However, only the Executive functions predicted intelligence. These findings provide information about how Executive functions develop and may contribute to helping develop students’ talents. They also highlight the importance of learning more about Divergent thinking.

Research on the propagation mechanisms and meso-mechanical responses of reflective cracking on the asphalt overlays on concrete airfield pavement by Fiber Bragg Grating sensing technology

This study evaluated the propagation mechanisms and dynamic meso-mechanical responses of reflective cracking on the asphalt overlays on concrete airfield pavement based on flexible Fiber Bragg Grating (FBG) sensors. The encapsulated FBG sensors were efficiently calibrated, possessing outstanding capability for the measurement of transverse expansion of lateral reflective cracking propagation. Virtual three-point bending test model was proposed and validated by macroscopic indoor experiments. The DEM model facilitated quantifying the proliferation of reflective cracks, unraveling the trajectory from micro-crack inception to visible macroscopic manifestation. Results indicated that the emergence and elongation of the composite structure experienced three phases: the initiation and accumulation of microcracks, the extension of reflective cracking, and the ultimate penetration. The DEM simulation and FBG sensors were recommended to establish a mutually reinforcing mechanism for nuanced validation of reflective crack formation on the composite structures of asphalt overlays on concrete airfield pavement.

Aircraft Upset Recovery Strategy and Pilot Assistance System Based on Reinforcement Learning

The upset state is an unexpected flight state, which is characterized by an unintentional deviation from normal operating parameters. It is difficult for the pilot to recover the aircraft from the upset state accurately and quickly. In this paper, an upset recovery strategy and pilot assistance system (PAS) based on reinforcement learning is proposed. The man–machine closed-loop system was established and the upset state, such as a high angle of attack and large attitude angle, was induced. The upset recovery problem was transformed into a sequential decision problem, and the Markov decision model of upset recovery was established by taking the deflection change of the control surface as the action. The proximal policy optimization (PPO) algorithm was selected for the strategy training. The adaptive pilot model and the reinforcement learning method proposed in this paper were used to make the aircraft recover from the upset state. Based on the correspondence between the flight state, the recovery method, and the recovery result, the aircraft upset recovery safety envelopes were formed, and the four-level upset recovery PAS with alarm warning, coordinated control, and autonomous recovery modes was constructed. The results of the digital virtual flight simulation and ground flight test show that compared with a traditional single pilot, the aircraft upset recovery strategy, the upset recovery safety envelopes, and the PAS established in this study could reduce the handling burden of the pilot and improve the success rate and effect of upset recovery. This research has certain theoretical reference values for flight safety and pilot training.

VR communication simulation with scripted dialog elicits HPA axis stress

Stress-inducing virtual reality (VR) systems have various applications in research, ranging from training to therapy to the observation of biological stress responses. Stress in VR can be evoked through environmental, cognitive, and social stimuli. Although various VR tasks can induce an autonomic nervous system (ANS) stress response, hypothalamic-pituitary-adrenal (HPA) axis stress responses have only been confirmed in VR for the virtual Trier social stress test (V-TSST). Understanding the impact of a wider variety of tasks on HPA-axis stress response could lead to the development of more effective stress relief measures and treatments. This study aims to clarify whether a virtual communication simulation, using a static procedure with a predetermined dialog, can evoke an HPA-axis stress response. Employing a virtual customer service system, we varied the intensity of the presented stress by changing the tone and gestures of the virtual customer. The findings confirm that HPA-axis stress responses can be elicited by such static virtual customer service training systems, and the stress responses can be adjusted by altering the avatar’s attitude. These findings suggest potential applications in research for observing human physiological responses to stress and development of stress reduction strategies, thereby affirming the effectiveness of VR in communication training.

Testing Structural Elements under Multiaxial Loading: A Numerical Model of the Bench to Understand and Predict Complex Boundary Conditions

Airworthiness certification requires proof of structure strength, which is performed generally through a building block approach. To achieve this, representative intermediate-scale experiments generated by test benches are, in general, needed, in addition to material characterization on a coupons scale and structure testing on a large scale. The VERTEX test bench can generate the combined loading of tension/compression-shear-pressure on structural elements and was modelled with Finite Elements to perform virtual testing, representative of its intermediate-scale specificity. The numerous bolted joints of the bench were modelled and their behavior was identified in previous tests, so the model could quantitatively estimate the transfer function of the bench, which is the relationship between the displacements imposed by the jacks and the resulting loads on a given sample. The VERTEX model was identified to represent load shapes and amplitudes based on a training set and was later confronted by a validation set of tests of tension and shear. A model with ideal boundary conditions was also developed for a comparison, but it failed to predict some load shape specificities and did not give any indication of the loading amplitude. Application cases of the developed model are shown to assess a range of virtual testing possibilities.

Mathematical Model of Impact Projectile Flight Dynamics as an Element of its Digital Twin

This paper gives the analysis of the structure and characteristics of the mathematical model of the impact projectile’s flight dynamics. The model is designed for being used as an element of the projectile’s digital twin. The model is based on differential motion equations of a gyro-stabilized solid with an axisymmetric mass distribution. Different types of angle variables were chosen for describing aerodynamics and formulating equations of motion. Non-linear (considering the nutation angle) dependences for aerodynamic coefficients are proposed. They are created by applying proven scientific concepts and research methods in aerodynamics of axisymmetric body and by comparing with known numerical and experimental results obtained in exterior ballistics of gyro-stabilized aviation and artillery projectiles. Special aspects of initial conditions for angles and angular velocity were also studied. Since the impact projectile is considered as an axially symmetric body, its self-rotation angle is not of practical inte rest. Using algebraic manipulations, the differential equation for this angle was eliminated from the set of equations. This has made it possible to significantly reduce stiff of the remaining system of differential equations. The Dormand-Prince method is recommended as a method of numerical integration. The method of the eight-order (with seventh-order uncertainty estimate) allows getting the high accurate solution of the differential equations set under relatively small computing costs. The model allows computing the projectile trajectory under various initial conditions, including the flight with high nutation angles up to 87°—89°. As a result, there is a possibility to determine the nature of the interaction between impact projectiles and typical targets (ricochet, surface effect, after-penetration effect) within a wide range of approach angles to the target’s surface (skin) unattainable during the full-scale tests. The possibility of solving similar problems allows to recommend the designed model as an element of the impact projectile’s digital twin intended for testing its exterior ballistics on the digital (virtual) test range. All testing calculations and final modeling were made by using the "GNU Octave" computational software package.

Virtual Reality Assessment of Attention Deficits in Traumatic Brain Injury: Effectiveness and Ecological Validity

Early detection is crucial for addressing attention deficits commonly associated with Traumatic brain injury (TBI), informing effective rehabilitation planning and intervention. While traditional neuropsychological assessments have been conventionally used to evaluate attention deficits, their limited ecological validity presents notable challenges. This study explores the efficacy and validity of a novel virtual reality test, the Computerized Battery for the Assessment of Attention Disorders (CBAAD), among a cohort of TBI survivors (n = 20), in comparison to a healthy control group (n = 20). Participants, ranging in age from 21 to 62 years, were administered a comprehensive neuropsychological assessment, including the CBAAD and the Attention Related Cognitive Errors Scale. While variations in attentional performance were observed across age cohorts, the study found no statistically significant age-related effects within either group. The CBAAD demonstrated sensitivity to attentional dysfunction in the TBI group, establishing its value as a comprehensive test battery for assessing attention in this specific population. Regression analyses demonstrated the CBAAD’s effectiveness in predicting real-life attentional errors reported by TBI patients. In summary, the CBAAD demonstrates sensitivity to attentional dysfunction in TBI patients and the ability to predict real-world attentional errors, establishing its value as a comprehensive test battery for assessing attention in this specific population. Its implementation holds promise for enhancing the early identification of attentional impairments and facilitating tailored rehabilitation strategies for TBI patients.

Virtual testing ground mathematical model design and it’s software realization in Simcenter AMESim

The object of the development is a virtual testing ground mathematical model with the road random profile irregularities for conducting simulation tests of vehicle dynamics. The work aim is to create a virtual testing ground mathematical model in the form of 3D-fields of irregularities and its software implementation in the Simcenter AMESim. To create a 3D-polygon model, the well-known theoretical knowledge for modeling various categories irregularities of ground surface are considered, differential equations for modeling profile realizations are compiled, profile realizations are simulated and 3D-fields of irregularities integrated into the Simcenter AMESim environment are created with the help of the obtained implementations. As a work result, a 3D-field random profile road irregularities mathematical model with a modeling technology description was obtained. A universal unit for modeling a virtual testing field with the ability to simulate roads of various irregularities categories was software implemented in the Simcenter AMESim. The created model is universal. It was designed for conducting virtual tests of various vehicles types when driving on various roads types. Due to a simulation modeling of vehicle dynamics when driving through irregularities fields, it becomes possible to measure, compare, control and regulate a large number of different cars parameters. The created block can be included in cars simulation models of any complexity level realized in Simcenter AMESim to conduct virtual tests of vehicle dynamics in conditions close to reality. Keywords mathematical model, virtual testing ground, unevenness 3D-field, random road profile, Simcenter AMESim

Performance of VisuALL virtual reality visual field testing in healthy children

BackgroundVirtual reality field testing may provide an alternative to standard automated perimetry. This study evaluates a virtual reality game-based automated perimetry in a healthy pediatric population. MethodsA prospective series of pediatric patients at one institution who performed VisuALL perimetry (Olleyes Inc, Summit, NJ) using a game-based algorithm. Participants were examined by an experienced pediatric optometrist or ophthalmologist, who confirmed that there was no evidence of ocular disease expected to affect visual fields. Testing was performed binocularly, with the child wearing their spectacle correction in place. Age, refractive error, test duration, false positives, and stereoacuity were evaluated for associations with performance on VisuALL, as defined by mean deviation (MD) and pattern standard deviation (PSD). ResultsA total of 191 eyes of 97 patients (54% female) were included, with a mean age of 11.9 ± 3.1 years. Detailed patient demographics and characteristics can be found in Table 1. The average MD was −1.82 ± 3.5 dB, with a mean foveal sensitivity of 32.0 ± 4.7 dB. Fifty-nine eyes (30.9%) had MD < −2 dB. Better performance, as assessed by MD and PSD, was associated with shorter test duration (P < 0.001) and older age (P < 0.001). False positives (P = 0.442), wearing spectacles (P = 0.092), Titmus stereoacuity (P = 0.197), and refractive error (P = 0.120) did not appear to be associated with improved performance, adjusting for age as a covariate. ConclusionsVisuALL virtual reality field testing was well tolerated in this pediatric study cohort. Older age and shorter test duration were associated with better performance on field testing.

A Physics-informed Deep Neural Network for Harmonization of CT Images.

An adversarial generative network was trained on virtual CT images acquired under various imaging conditions using a virtual imaging platform with 40 computational patient models. These models featured anthropomorphic lungs with different levels of pulmonary diseases, including nodules and emphysema. Imaging was conducted using a validated CT simulator at two dose levels and varying reconstruction kernels. The trained model was tested on an independent virtual test dataset and two clinical datasets. On the virtual test set, the harmonizer improved the structural similarity index from 79.3 ±16.4% to 95.8 ±1.7%, normalized mean squared error from 16.7 ±9.7% to 9.2 ±1.7%, and peak signal-to-noise ratio from 27.7 ±3.7dB to 32.2 ±1.6dB. Moreover, the harmonized images yielded more precise quantification of emphysema-based imaging biomarkers for lung attenuation, LAA-950 from 5.6 ±8.7% to 0.23 ±0.16%, Perc15 from 43.4 ±45.4 HU to 20.0 ±7.5 HU, and Lung Mass from 0.3 ±0.3 g to 0.1 ±0.2 g. In clinical data, the harmonizer reduced biomarker variability by an average of 70%. For lung nodules, harmonized images improved the detectability index by 6.5-fold and DNN-based precision by 6%. The proposed harmonizer significantly enhances image quality and quantification accuracy in CT imaging. The study demonstrated the potential utility of image harmonization for consistent CT image quality and reliable quantification, which is crucial for clinical applications and patient management.

Toward Sound Localization Testing in Virtual Reality to Aid in the Screening of Auditory Processing Disorders.

Sound localization testing is key for comprehensive hearing evaluations, particularly in cases of suspected auditory processing disorders. However, sound localization is not commonly assessed in clinical practice, likely due to the complexity and size of conventional measurement systems, which require semicircular loudspeaker arrays in large and acoustically treated rooms. To address this issue, we investigated the feasibility of testing sound localization in virtual reality (VR). Previous research has shown that virtualization can lead to an increase in localization blur. To measure these effects, we conducted a study with a group of normal-hearing adults, comparing sound localization performance in different augmented reality and VR scenarios. We started with a conventional loudspeaker-based measurement setup and gradually moved to a virtual audiovisual environment, testing sound localization in each scenario using a within-participant design. The loudspeaker-based experiment yielded results comparable to those reported in the literature, and the results of the virtual localization test provided new insights into localization performance in state-of-the-art VR environments. By comparing localization performance between the loudspeaker-based and virtual conditions, we were able to estimate the increase in localization blur induced by virtualization relative to a conventional test setup. Notably, our study provides the first proxy normative cutoff values for sound localization testing in VR. As an outlook, we discuss the potential of a VR-based sound localization test as a suitable, accessible, and portable alternative to conventional setups and how it could serve as a time- and resource-saving prescreening tool to avoid unnecessarily extensive and complex laboratory testing.

Spatial Design Research on Digital Media Technology Intervention in Immersive Art Theory Exhibition Venues

Abstract The article takes the application of digital media technology in the spatial layout design of art exhibition halls as the entry point, and utilizes Web technology and the integrated simulation platform of urban VRGIS to establish the virtual space of immersive art exhibition halls. The article obtains binocular imaging data through binocular visual imaging model and solves the three-dimensional coordinate system by using the method of polar geometric constraints, and then reconstructs the three-dimensional space through the point cloud data to realize the design of the virtual space of the immersive art exhibition hall. The article evaluates the effectiveness of the immersive art gallery virtual space from three aspects: interactivity, DPI recovery value and eye movement data visualization. It is found that users are most effective with direct interaction within an interaction depth of 1.1 m to 1.7 m. In comparison, ray interaction is more appropriate when the interaction depth exceeds 2.3 m. Applying the method of this paper, the global DPI recovery value of the immersive art gallery can reach 89.67%, and the pupil diameter of the subjects can reach about 5.79 mm in the virtual space test over 160 seconds. In this paper, digital media technology can more effectively realize the immersive presentation of art theories, to better satisfy people’s growing spiritual needs and provide more diverse cultural experiences.