Observing an expert's action swapped with an observer's face increases corticospinal excitability during combined action observation and motor imagery.

This study aimed to examine whether observing an expert's action swapped with an observer's face increases corticospinal excitability during combined action observation and motor imagery (AOMI). Twelve young males performed motor imagery of motor tasks with different difficulties while observing the actions of an expert performer and an expert performer with a swapped face. Motor tasks included bilateral wrist dorsiflexion (EASY) and unilateral two-ball rotating motions (DIFF). During the AOMI of EASY and DIFF, single-pulse transcranial magnetic stimulation was delivered to the left primary motor cortex, and motor-evoked potentials (MEPs) were obtained from the extensor carpi ulnaris and first dorsal interosseous muscles of the right upper limb, respectively. Visual analogue scale (VAS) assessed the subjective similarity of the expert performer with the swapped face in the EASY and DIFF to the participants themselves. The MEP amplitude in DIFF was larger in the observation of the expert performer with the swapped face than that of the expert performer (P = 0.012); however, the corresponding difference was not observed in EASY (P = 1.000). The relative change in the MEP amplitude from observing the action of the expert performer to that of the expert performer with the swapped face was positively correlated with VAS only in DIFF (r = 0.644, P = 0.024). These results indicate that observing the action of an expert performer with the observer's face enhances corticospinal excitability during AOMI, depending on the task difficulty and subjective similarity between the expert performer being observed and the observer.

Systematic Review of Augmented Reality Training Systems.

Recent augmented reality (AR) advancements have enabled the development of effective training systems, especially in the medical, rehabilitation, and industrial fields. However, it is unclear from the literature what the intrinsic value of AR to training is and how it differs across multiple application fields. In this work, we gathered and reviewed the prototypes and applications geared towards training the intended user's knowledge, skills, and abilities. Specifically, from IEEE Xplore plus other digital libraries, we collected 64 research papers present in high-impact publications about augmented reality training systems (ARTS). All 64 papers were then categorized according to the training method used, and each paper's evaluations were identified by validity. The summary of the results shows trends in the training methods and evaluations that incorporate ARTS in each field. The narrative synthesis illustrates the different implementations of AR for each of the training methods. In addition, examples of the different evaluation types of the current ARTS are described for each of the aforementioned training methods. We also investigated the different training strategies used by the prevailing ARTS. The insights gleaned from this review can suggest standards for designing ARTS regarding training strategy, and recommendations are provided for the implementation and evaluation of future ARTS.

Cross-talk elimination for lenslet array near eye display based on eye-gaze tracking.

Lenslet array (LA) near-eye displays (NEDs) are a recent technical development that creates a virtual image in the field of view of one or both eyes. A problem occurs when the user's pupil moves out of the LA-NED eye box (i.e., cross-talk) making the image look doubled or ghosted. It negatively impacts the user experience. Although eye-gaze tracking can mitigate this problem, the effect of the solution has not been studied to understand the impact of pupil size and human perception. In this paper, we redefine the cross-talk region as the practical pupil movable region (PPMR50), which differs from eye box size because it considers pupil size and human visual perception. To evaluate the effect of eye-gaze tracking on subjective image quality, three user studies were conducted. From the results, PPMR50 was found to be consistent with human perception, and cross-talk elimination via eye-gaze tracking was better understood in a static gaze scenario. Although the system latency prevented the complete elimination of cross-talk for fast movements or large pupil changes, the problem was greatly alleviated. We also analyzed system delays based on PPMR50, which we newly defined in this paper and provided an optimization scheme to meet the maximum eyeball rotation speed.

Robot touch with speech boosts positive emotions.

A gentle touch is an essential part of human interaction that produces a positive care effect. Previously, robotics studies have shown that robots can reproduce a gentle touch that elicits similar, positive emotional responses in humans. However, whether the positive emotional effects of a robot's touch combined with speech can be enhanced using a multimodal approach remains unclear. This study supports the hypothesis that a multimodal interaction combining gentle touch and speech by a robot enhances positive emotional responses. Here, we conducted an experiment using a robotic arm to perform a gentle touch combined with speech and compared three conditions: touch alone, speech alone, and touch with speech. We assessed participants' subjective ratings of valence, arousal, and human likeliness using subjective emotional responses. Furthermore, we recorded facial electromyography (EMG) from the corrugator supercilii and zygomaticus major muscles and measured skin conductance levels (SCLs) as physiological emotional responses. Our results show that touch combined with speech elicited higher subjective valence and arousal ratings, stronger zygomaticus major EMG and SCL activities than touch alone. The results suggest that the positive emotional effects of robotic touch can be boosted by combining elements of speech.

DFusion: Denoised TSDF Fusion of Multiple Depth Maps with Sensor Pose Noises.

The truncated signed distance function (TSDF) fusion is one of the key operations in the 3D reconstruction process. However, existing TSDF fusion methods usually suffer from the inevitable sensor noises. In this paper, we propose a new TSDF fusion network, named DFusion, to minimize the influences from the two most common sensor noises, i.e., depth noises and pose noises. To the best of our knowledge, this is the first depth fusion for resolving both depth noises and pose noises. DFusion consists of a fusion module, which fuses depth maps together and generates a TSDF volume, as well as the following denoising module, which takes the TSDF volume as the input and removes both depth noises and pose noises. To utilize the 3D structural information of the TSDF volume, 3D convolutional layers are used in the encoder and decoder parts of the denoising module. In addition, a specially-designed loss function is adopted to improve the fusion performance in object and surface regions. The experiments are conducted on a synthetic dataset as well as a real-scene dataset. The results prove that our method outperforms existing methods.

Surface Remeshing: A Systematic Literature Review of Methods and Research Directions.

Triangle meshes are used in many important shape-related applications including geometric modeling, animation production, system simulation, and visualization. However, these meshes are typically generated in raw form with several defects and poor-quality elements, obstructing them from practical application. Over the past decades, different surface remeshing techniques have been presented to improve these poor-quality meshes prior to the downstream utilization. A typical surface remeshing algorithm converts an input mesh into a higher quality mesh with consideration of given quality requirements as well as an acceptable approximation to the input mesh. In recent years, surface remeshing has gained significant attention from researchers and engineers, and several remeshing algorithms have been proposed. However, there has been no survey article on remeshing methods in general with a defined search strategy and article selection mechanism covering the recent approaches in surface remeshing domain with a good connection to classical approaches. In this article, we present a survey on surface remeshing techniques, classifying all collected articles in different categories and analyzing specific methods with their advantages, disadvantages, and possible future improvements. Following the systematic literature review methodology, we define step-by-step guidelines throughout the review process, including search strategy, literature inclusion/exclusion criteria, article quality assessment, and data extraction. With the aim of literature collection and classification based on data extraction, we summarized collected articles, considering the key remeshing objectives, the way the mesh quality is defined and improved, and the way their techniques are compared with other previous methods. Remeshing objectives are described by angle range control, feature preservation, error control, valence optimization, and remeshing compatibility. The metrics used in the literature for the evaluation of surface remeshing algorithms are discussed. Meshing techniques are compared with other related methods via a comprehensive table with indices of the method name, the remeshing challenge met and solved, the category the method belongs to, and the year of publication. We expect this survey to be a practical reference for surface remeshing in terms of literature classification, method analysis, and future prospects.

Effects of vibrotactile-enhanced music-based intervention on sensorimotor control capacity in the hand of an aging brain: a pilot feasibility randomized crossover trial.

BACKGROUND: Music-based interventions (MBI), using music as a therapeutic medium, has been utilized as a promising strategy for motor relearning and shaping. However, currently, MBI with active performance training is restricted to being extensively applied for patients with various levels of defects in fine motor skills and cognitive functions. Therefore, the integration of vibrotactile stimulation with MBI has been adopted as a motor training strategy intended to enhance motor learning through use of vibration stimuli. The current study was designed to investigate differences in the sensorimotor performance of older adults' hands under baseline, a single session of active MBI, and vibrotactile-enriched MBI conditions. METHODS: Thirty healthy older adults were recruited and randomized to receive either the single session of 30-min of vibrotactile-enriched MBI or 30-min of active MBI at the beginning of the experiment. After a one-week washout period, they switched their treatment programs and then were assessed to study the training effects of both approaches through measuring precision pinch performance, hand function, and sensory status. RESULTS: The results of the Pinch-Holding-Up Activity test revealed a statistically significant difference in the FRpeak parameter (F = 14.37, p < 0.001, η2p = 0.507) under the vibrotactile-enriched MBI condition compared to the baseline and active MBI conditions. In addition, significant beneficial effects were found on the results of the barognosis (F = 19.126, p < 0.001, η2p = 0. 577) and roughness differentiation subtests (F = 15.036, p < 0.001, η2p = 0.518) in the Manual Tactile Test for the participants in the vibrotactile-enriched MBI group. In addition, the participants under both the active MBI and vibrotactile-enriched MBI conditions exhibited better performance in the three subtests of the Purdue Pegboard Test as compared to under the baseline condition (p < 0.016). CONCLUSIONS: The findings indicated that vibrotactile-enriched MBI potentially improves the precision pinch performance of hands in healthy older adults. In addition, the add-on effect of vibrotactile stimulation to the MBI condition provides beneficial effects on the sensory functions of the upper extremities. TRIAL REGISTRATION: NCT04802564 . Date of registration: 15/03/2021. The first posted date: 17/03/2021.

No Interface, No Problem: Gesture Recognition on Physical Objects Using Radar Sensing.

Physical objects are usually not designed with interaction capabilities to control digital content. Nevertheless, they provide an untapped source for interactions since every object could be used to control our digital lives. We call this the missing interface problem: Instead of embedding computational capacity into objects, we can simply detect users' gestures on them. However, gesture detection on such unmodified objects has to date been limited in the spatial resolution and detection fidelity. To address this gap, we conducted research on micro-gesture detection on physical objects based on Google Soli's radar sensor. We introduced two novel deep learning architectures to process range Doppler images, namely a three-dimensional convolutional neural network (Conv3D) and a spectrogram-based ConvNet. The results show that our architectures enable robust on-object gesture detection, achieving an accuracy of approximately 94% for a five-gesture set, surpassing previous state-of-the-art performance results by up to 39%. We also showed that the decibel (dB) Doppler range setting has a significant effect on system performance, as accuracy can vary up to 20% across the dB range. As a result, we provide guidelines on how to best calibrate the radar sensor.

Viral-derived DNA invasion and individual variation in an Indonesian population of large flying fox Pteropus vampyrus.

Here, we performed next-generation sequencing (NGS) on six large flying foxes (Pteropus vampyrus) collected in Indonesia. Seventy-five virus species in the liver tissue of each specimen were listed. Viral homologous sequences in the bat genome were identified from the listed viruses. This finding provides collateral evidence of viral endogenization into the host genome. We found that two of the six specimens bore partial sequences that were homologous to the plant pathogens Geminiviridae and Luteoviridae. These sequences were absent in the P. vampyrus chromosomal sequences. Hence, plant viral homologous sequences were localized to the hepatocytes as extrachromosomal DNA fragments. Therefore, this suggests that the bat is a potential carrier or vector of plant viruses. The present investigation on wild animals offered novel perspectives on viral invasion, variation, and host interaction.

Robust Reflectance Estimation for Projection-Based Appearance Control in a Dynamic Light Environment.

We present a novel method that robustly estimates the reflectance, even in an environment with dynamically changing light. To control the appearance of an object by using a projector-camera system, an appropriate estimate of the object's reflectance is vital to the creation of an appropriate projection image. Most conventional estimation methods assume static light conditions; however, in practice, the appearance is affected by both the reflectance and environmental light. In an environment with dynamically changing light, conventional reflectance estimation methods require calibration every time the conditions change. In contrast, our method requires no additional calibration because it simultaneously estimates both the reflectance and environmental light. Our method is based on the concept of creating two different light conditions by switching the projection at a rate higher than that perceived by the human eye and captures the images of a target object separately under each condition. The reflectance and environmental light are then simultaneously estimated by using the pair of images acquired under these two conditions. We implemented a projector-camera system that switches the projection on and off at 120 Hz. Experiments confirm the robustness of our method when changing the environmental light. Further, our method can robustly estimate the reflectance under practical indoor lighting conditions.

Positive Emotion Amplification by Representing Excitement Scene with TV Chat Agents.

This paper proposes emotion amplification for TV chat agents allowing users to get more excited in TV sports programs, and a model that estimates the excitement level of TV programs based on the number of social comment posts. The proposed model extracts the exciting intervals from social comments to the program scenes. By synchronizing recorded video streams and the intervals, the agents may talk with the user dynamically changing the frequency and volume of upbeat utterances, increasing the excitement of the user. To test these agents, participants watched TV content under three conditions: without an agent, with four agents that utter with a flat voice, and with four agents with emotion amplification. Results from 24 young adult Japanese individuals showed that their arousal of participants' subjective and physiological emotional responses were boosted because of the agents, enhancing their motivation to interact with the agent in the future. With empirical evidence, this paper supports these expectations and demonstrates that these agents can amplify the positive emotions of TV watchers, enhancing their motivation to interact with the agent in the future.

Handheld Guides in Inspection Tasks: Augmented Reality versus Picture.

Inspection tasks focus on observation of the environment and are required in many industrial domains. Inspectors usually execute these tasks by using a guide such as a paper manual, and directly observing the environment. The effort required to match the information in a guide with the information in an environment and the constant gaze shifts required between the two can severely lower the work efficiency of inspector in performing his/her tasks. Augmented reality (AR) allows the information in a guide to be overlaid directly on an environment. This can decrease the amount of effort required for information matching, thus increasing work efficiency. AR guides on head-mounted displays (HMDs) have been shown to increase efficiency. Handheld AR (HAR) is not as efficient as HMD-AR in terms of manipulability, but is more practical and features better information input and sharing capabilities. In this study, we compared two handheld guides: an AR interface that shows 3D registered annotations, that is, annotations having a fixed 3D position in the AR environment, and a non-AR picture interface that displays non-registered annotations on static images. We focused on inspection tasks that involve high information density and require the user to move, as well as to perform several viewpoint alignments. The results of our comparative evaluation showed that use of the AR interface resulted in lower task completion times, fewer errors, fewer gaze shifts, and a lower subjective workload. We are the first to present findings of a comparative study of an HAR and a picture interface when used in tasks that require the user to move and execute viewpoint alignments, focusing only on direct observation. Our findings can be useful for AR practitioners and psychology researchers.

Augmented Reality versus Virtual Reality for 3D Object Manipulation.

Virtual Reality (VR) Head-Mounted Displays (HMDs) are on the verge of becoming commodity hardware available to the average user and feasible to use as a tool for 3D work. Some HMDs include front-facing cameras, enabling Augmented Reality (AR) functionality. Apart from avoiding collisions with the environment, interaction with virtual objects may also be affected by seeing the real environment. However, whether these effects are positive or negative has not yet been studied extensively. For most tasks it is unknown whether AR has any advantage over VR. In this work we present the results of a user study in which we compared user performance measured in task completion time on a 9 degrees of freedom object selection and transformation task performed either in AR or VR, both with a 3D input device and a mouse. Our results show faster task completion time in AR over VR. When using a 3D input device, a purely VR environment increased task completion time by 22.5 percent on average compared to AR ( ). Surprisingly, a similar effect occurred when using a mouse: users were about 17.3 percent slower in VR than in AR ( ). Mouse and 3D input device produced similar task completion times in each condition (AR or VR) respectively. We further found no differences in reported comfort.

Augmented reality as multimedia: the case for situated vocabulary learning.

Augmented reality (AR) has the potential to create compelling learning experiences. However, there are few research works exploring the design and evaluation of AR for educational settings. In our research, we treat AR as a type of multimedia that is situated in authentic environments and apply multimedia learning theory as a framework for developing our educational applications. We share our experiences in developing a handheld AR system and one specific use case, namely, situated vocabulary learning. Results of our evaluations show that we are able to create AR applications with good system usability. More importantly, our preliminary evaluations show that AR may lead to better retention of words and improve student attention and satisfaction.

Toward Standard Usability Questionnaires for Handheld Augmented Reality.

Usability evaluations are important to improving handheld augmented reality (HAR) systems. However, no standard questionnaire considers perceptual and ergonomic issues found in HAR. The authors performed a systematic literature review to enumerate these issues. Based on these issues, they created a HAR usability scale that consists of comprehensibility and manipulability scales. These scales measure general system usability, ease of understanding the information presented, and ease of handling the device. The questionnaires' validity and reliability were evaluated in four experiments, and the results show that the questionnaires consistently correlate with other subjective and objective measures of usability. The questionnaires also have good reliability based on the Cronbach's alpha. Researchers and professionals can directly use these questionnaires to evaluate their own HAR applications or modify them with the insights presented in this article.

Geometrically-correct projection-based texture mapping onto a deformable object.

Projection-based Augmented Reality commonly employs a rigid substrate as the projection surface and does not support scenarios where the substrate can be reshaped. This investigation presents a projection-based AR system that supports deformable substrates that can be bent, twisted or folded. We demonstrate a new invisible marker embedded into a deformable substrate and an algorithm that identifies deformations to project geometrically correct textures onto the deformable object. The geometrically correct projection-based texture mapping onto a deformable marker is conducted using the measurement of the 3D shape through the detection of the retro-reflective marker on the surface. In order to achieve accurate texture mapping, we propose a marker pattern that can be partially recognized and can be registered to an object’s surface. The outcome of this work addresses a fundamental vision recognition challenge that allows the underlying material to change shape and be recognized by the system. Our evaluation demonstrated the system achieved geometrically correct projection under extreme deformation conditions. We envisage the techniques presented are useful for domains including prototype development, design, entertainment and information based AR systems.

In vitro assessment of factors affecting the apparent diffusion coefficient of Jurkat cells using bio-phantoms.

It is well known that many tumor tissues show lower apparent diffusion coefficient (ADC) values, and that several factors are involved in the reduction of ADC values. The aim of this study was to clarify how much each factor contributes to decreases in ADC values. We investigate the roles of cell density, extracellular space, intracellular factors, apoptosis and necrosis in ADC values using bio-phantoms. The ADC values of bio-phantoms, in which Jurkat cells were encapsulated by gellan gum, were measured by a 1.5-Tesla magnetic resonance imaging device with constant diffusion time of 30sec. Heating at 42℃ was used to induce apoptosis while heating at 48℃ was used to induce necrosis. Cell death after heating was evaluated by flow cytometric analysis and electron microscopy. The ADC values of bio-phantoms including non-heated cells decreased linearly with increases in cell density, and showed a steep decline when the distance between cells became less than 3µm. The analysis of ADC values of cells after destruction of cellular structures by sonication suggested that approximately two-thirds of the ADC values of cells originate from their cellular structures. The ADC values of bio-phantoms including necrotic cells increased while those including apoptotic cells decreased. This study quantitatively clarified the role of the cellular factors and the extracellular space in determining the ADC values produced by tumor cells. The intermediate diffusion time of 30msec might be optimal to distinguish between apoptosis and necrosis.

Work step indication with grid-pattern projection for demented senior people.

This paper proposes a work step indication method for supporting daily work with a grid-pattern projection. To support an independent life of demented senior people, it is desirable that an instruction is easy to understand visually and not complicated. The proposed method in this paper uses a range image sensor and a camera in addition to a projector. A 3D geometry of a target scene is measured by the range image sensor, and the grid-pattern is projected onto the scene directly. Direct projection of the work step is easier to be associated with the target objects around the assisted person, and the grid-pattern is a solution to indicate the spatial instruction. A prototype has been implemented and has demonstrated that the proposed grid-pattern projection is easy to show the work step.

Influence of permittivity and electrical conductivity on image pattern of MRI.

In proton density-weighted (PDW) MR imaging, the patterns of signal intensity vary depending on the imaged material, and change with the flip angle (FA) applied to the imaged material. The correlation between the pre-determined FA and the actual FA applied to imaged objects was investigated using 4 types of phantoms having different dielectric properties. PDW images were acquired using the spin-echo (SE) method and different pre-determined FA. Dependency of the signal intensity distribution in the phantom on the pre-determined FA differed among phantoms: patterns for water and 0.402 w/w% saline solution phantoms changed with the pre-determined FA, whereas those for olive oil and 4.02 w/w% saline solution phantoms were barely affected by the pre-determined FA. Causes of these phenomena were considered to be the differences between the pre-determined FA and the actual FA among the phantoms; differences were also influenced by the positioning of the phantom. Our study showed that the actual FA in the phantom is greater than the pre-determined FA in high permittivity media, whereas it is reduced by an increased conductivity of the media.

Quality assurance: recommended guidelines for safe heating by capacitive-type heating technique to treat patients with metallic implants.

This article is a redissemination of the previous Japanese Quality Assurance Guide guidelines. Specific absorption rate and temperature distribution were investigated with respect to various aspects including metallic implant size and shape, insertion site, insertion direction, blood flow and heating power, and simulated results were compared with adverse reactions of patients treated by radio frequency capacitive-type heating. Recommended guidelines for safe heating methods for patients with metallic implants are presented based on our findings.