Visual Feedback Research Articles

Combined Effects of Listening to Preferred Music and Video Feedback, during Warm-Up, on Physical Performance in Young Kickboxers.

Although studies have indicated that the prior use of video feedback and music listening separately improves physical performance and positive feelings in various sports, to our knowledge, no studies have investigated their combined effect in combat-sports-specific tasks. The aim of this study was to determine the combined effect of listening to preferred music and video feedback on aerobic and anaerobic performance in male kickboxers. In a counterbalanced crossover study design, twenty kickboxers underwent three kicking exercises under one of three conditions: (1) control condition, (2) combined listening to preferred music and video feedback, and (3) video feedback during 10-min of rope warm-up. Kickboxers performed a ten-second kicking test, multiple ten-second kick test, and progressive taekwondo test. The total number of kicks, fatigue index, heart rate, rate of perceived exertion, and feeling scale were measured. The combined music and video feedback condition improved the number of kicks with a better positive feeling scale (F ≥ 7.4, p ≤ 0.002, ηp2 ≥ 0.28) than the video feedback and control conditions in all three kicking exercises, while the video feedback alone led to better kick performances and a better feeling scale than the control condition in the ten-second and multiple ten-second kicking tests (p ≤ 0.016). The combined listening to preferred music and video feedback condition was more effective at enhancing the positive feeling scale and repeated roundhouse kick performance. Future investigations should examine the application of video feedback and listening to music in various kickboxing tasks including punches and kicks.

Assessing the quality of chest compressions with a DIY low-cost manikin (LoCoMan) versus a standard manikin: a quasi-experimental study in primary education

Extending the access to cardiopulmonary resuscitation (CPR) training to a wider public is an important step in increasing survivability of out-of-hospital cardiac arrest. However, often price and maintenance of CPR manikins are barriers that prevent training at schools. This study aims to evaluate the learning of hands-only (HO) CPR by practicing with a low-cost manikin (LoCoMan) with visual qualitative feedback and to compare the results with the skills acquired by practice on a conventional manikin. A quasi-experimental study with 193 schoolchildren (10 to 12 years old) who were allocated to two groups: the LoCoMan group was taught via an integrative approach (science combined with physical education (PE)) and practiced on a handmade manikin, and a control group practiced in a traditional setting with a commercial manikin (Resusci Junior, Laerdal, Norway). All participants practiced for 1 hands-on skill session before performing a post-test on an instrumented CPR manikin. The outcomes including HO-CPR performance variables were compared between groups. The LoCoMan and control groups both achieved acceptable percentage of HO-CPR quality (57% and 71%, p = 0.004). Among 6th-graders, there were no significant differences in HO-CPR quality between LoCoMan 68% and control 71%, p = 0.66. The control group achieved better chest compression depth while the LoCoMan group showed more compressions with adequate chest recoil. Conclusion: Schoolchildren are able to build and use a low-cost manikin with visual feedback. The integrative learning approach used in this study may be a feasible alternative methodology for training and learning HO-CPR in schools when commercial manikins are not available.What is Known:• Access to CPR training should be universal and independent of age, location, financial means, or access to qualified instructors.• Scientific societies promote the implementation of CPR in schools, so that teachers and schoolchildren can play a multiplier role in their environment, but the gap in CPR learning is related to cultural, economic factors or access to resources and materials.What is New:• LoCoMan may be a useful device for teaching and learning CPR in schoolchildren from the age of 10 and upwards.• LOCOMAN shows that it is feasible and possible to build a low-cost manikin (about €5 in the European Region) and to integrate it into an integrative educational project, and outlines how this could be done. this approach can be an incentive for teachers to attempt teaching CPR, but also for education outside the formal environment.

Video mirror feedback induces more extensive brain activation compared to the mirror box: an fNIRS study in healthy adults

BackgroundMirror therapy (MT) has been shown to be effective for motor recovery of the upper limb after a stroke. The cerebral mechanisms of mirror therapy involve the precuneus, premotor cortex and primary motor cortex. Activation of the precuneus could be a marker of this effectiveness. MT has some limitations and video therapy (VT) tools are being developed to optimise MT. While the clinical superiority of these new tools remains to be demonstrated, comparing the cerebral mechanisms of these different modalities will provide a better understanding of the related neuroplasticity mechanisms.MethodsThirty-three right-handed healthy individuals were included in this study. Participants were equipped with a near-infrared spectroscopy headset covering the precuneus, the premotor cortex and the primary motor cortex of each hemisphere. Each participant performed 3 tasks: a MT task (right hand movement and left visual feedback), a VT task (left visual feedback only) and a control task (right hand movement only). Perception of illusion was rated for MT and VT by asking participants to rate the intensity using a visual analogue scale. The aim of this study was to compare brain activation during MT and VT. We also evaluated the correlation between the precuneus activation and the illusion quality of the visual mirrored feedback.ResultsWe found a greater activation of the precuneus contralateral to the visual feedback during VT than during MT. We also showed that activation of primary motor cortex and premotor cortex contralateral to visual feedback was more extensive in VT than in MT. Illusion perception was not correlated with precuneus activation.ConclusionVT led to greater activation of a parieto-frontal network than MT. This could result from a greater focus on visual feedback and a reduction in interhemispheric inhibition in VT because of the absence of an associated motor task. These results suggest that VT could promote neuroplasticity mechanisms in people with brain lesions more efficiently than MT.Clinical trial registrationNCT04738851.

Top of the Atmosphere Shortwave Arctic Cloud Feedbacks: A Comparison of Diagnostic Methods

AbstractThe cloud feedback may result in amplification or damping of Arctic warming. Two common techniques used to diagnose the top‐of‐the‐atmosphere cloud feedback are the Adjusted Cloud Radiative Effect (AdjCRE) method and the Cloud Radiative Kernel (CRK) method. We apply both to CMIP5 and CMIP6 model data, finding that the AdjCRE calculated Arctic shortwave cloud feedback is twice as correlated with sea ice loss in CMIP5, and four times in CMIP6, as the CRK method. We find that the CRK method produces Arctic all‐sky residual percentages exceeding 20% in 15 of 18 models. We use the CRK method to decompose the feedback in CMIP5 and CMIP6 finding that its median value changed from negative to positive driven by a less‐negative cloud optical depth feedback. Despite its lack of closure, we conclude that the CRK method is better suited for Arctic SW feedbacks as it is less impacted by surface albedo changes.

Additional visual information on postural control mechanisms in Parkinson's disease: a pilot study

Additional visual information on postural control mechanisms in Parkinson's disease: a pilot study

Dual laser based optical feedback cavity enhanced absorption spectroscopy by polarization division multiplexing

This article presents a dual laser-based optical feedback cavity-enhanced absorption spectroscopy technique using polarization division multiplexing. The technique involves two laser beams with orthogonal polarization that enter a V-shaped cavity from two injection directions. This allows for independent control of feedback phase and eliminates the need for an optical component to combine the beams. The two lasers are detected separately at the two ends of the cavity. Additionally, a differential process is proposed to mitigate residual interference between the two lasers. By employing this technique, simultaneous detection of CH4, CO2 and H2O is achieved, resulting in a detection sensitivity of approximately 2 × 10−11 cm−1. Despite using a moderate cavity finesse in our spectrometer, the minimal detectable concentration for the gases is comparable to that of superior gas analyzers using cavity ringdown spectroscopy (CRDS).

Artificial intelligence and robotic surgical education

There are numerous barriers in robotic surgical training, including reliance on observational learning, low-quality feedback, and inconsistent assessment. Artificial intelligence (AI) offers potential solutions to these central problems in robotic surgical education and may allow for more efficient and efficacious training. Three key areas in which AI has particular relevance to robotic surgical education are video labeling, feedback, and assessment. Video labeling refers to the automated designation of prespecified categories to operative videos. Numerous prior studies have applied AI for video labeling, particularly for retrospective educational review after an operation. Video labeling allows learners and their instructors to rapidly identify critical parts of an operative video. We recommend incorporating AI-based video labeling into robotic surgical education where available. AI also offers a mechanism by which reliable feedback can be provided in robotic surgery. Feedback through AI harnesses automated performance metrics (APMs) and natural language processing (NLP) to provide actionable and descriptive plans to learners while reducing faculty assessment burden. We recommend combining supervised AI-generated, APM-based feedback with expert-based feedback to allow surgeons and trainees to reflect on metrics like bimanual dexterity and efficiency. Finally, summative assessment by AI could allow for automated appraisal of surgeons or surgical trainees. However, AI-based assessment remains limited by concerns around bias and opaque processes. Several studies have applied computer vision to compare AI-based assessment with expert-completed rating scales, though such work remains investigational. At this time, we recommend against the use of AI for summative assessment pending additional validity evidence. Overall, AI offers solutions and promising future directions by which to address multiple educational challenges in robotic surgery. Through advances in video labeling, feedback, and assessment, AI has demonstrated ways by which to increase the efficiency and efficacy of robotic surgical education.

Demonstration of the parametric instability suppression through optical feedback

Demonstration of the parametric instability suppression through optical feedback

Does Viewing Mirror-Reflected Body Image Affect Static and Dynamic Standing Balance?

In the present study, we examined the immediate effect of allowing healthy participants to view their mirror-reflected body image on static and dynamic balance. We placed a mirror to allow participants to frontally view their own body image while maintaining a quiet stance or while engaged in a dynamic postural standing task. On measures of body sway during quiet stance, there were no effects of this visual feedback, supporting the view that human beings have no central mechanism for viewing the mirror-reflected body image to control body sway during quiet stance. However, the body deviated forward during quiet stance while viewing the mirror-reflected body image, indicating that viewing the mirror-reflected body image contributed to the anterior-posterior positioning of the body, as mediated by an ankle control strategy. For the dynamic standing task, viewing the body image induced unstable peaks of rhythmic lateral shifting of the body weight over the feet. This indicates that viewing the body image caused unstable motor commands for rhythmic lateral weight shifting. When participants made a transition from a bipedal to a unipedal stance in response to a cue, viewing the body image shortened the onset latency of the body sway. Accordingly, viewing the body image seemed to accelerate the motor execution involved in lateral weight shifting, possibly due to predictive activation of the motor system before movement onset. Considered collectively, we found static and dynamic stance balance to be influenced by viewing one's mirror-reflected body image. Viewing the mirror-reflected body image may be a means of changing static and dynamic balance in patients with impaired postural control.

Vision-based adaptive LT sliding mode admittance control for collaborative robots with actuator saturation

Abstract In this paper, we propose a novel vision-based adaptive leakage-type (LT) sliding mode admittance control for actuator-constrained collaborative robots to realize the synchronous control of the precise path following and compliant interaction force. Firstly, we develop a vision-admittance-based model to couple the visual feedback and force sensing in the image feature space so that a reference image feature trajectory can be obtained concerning the contact force command and predefined trajectory. Secondly, considering the system uncertainty, external disturbance, and torque constraints of collaborative robots in reality, we propose an adaptive sliding mode controller in the image feature space to perform precise trajectory tracking. This controller employs a leakage-type (LT) adaptive control law to reduce the side effects of system uncertainties without knowing the upper bound of system uncertainties. Moreover, an auxiliary dynamic is considered in this controller to overcome the joint torque constraints. Finally, we prove the convergence of the tracking error with the Lyapunov stability analysis and operate various semi-physical simulations compared to the conventional adaptive sliding mode and parallel vision/force controller to demonstrate the efficacy of the proposed controller. The simulation results show that compared with the controller mentioned above, the path following accuracy and interaction force control precision of the proposed controller increased by 50% and achieved faster convergence.

Telepresence augmentation for visual and haptic guided immersive teleoperation of industrial manipulator

Teleoperation under human guidance has become an effective solution to extend human’s reach in various environments. However, the teleoperation system still faces challenges of insufficient sense of both visual and haptic feedback from remote environments, which results in the inadequate guidance for the operator. In this paper, a visual/haptic integrated perception and reconstruction system (VHI-PRS) is developed to provide the operator with 3D visual information and effective haptic guidance. Specifically, a visual-based telepresence augmentation method is proposed to provide the operator with virtual-reality combined visual telepresence, where the real point cloud model is directly superimposed on virtual manipulator to avoid the time-consuming process of mesh model rendering. With the utilization of visual information, a haptic-based telepresence augmentation method is proposed to provide the operator with comprehensive force feedback, including the virtual guiding force, virtual repulsive force and real-time interactive force, which greatly helps reduce the workload of operator. Finally, a user study on grab-place task is carried out to verify the effectiveness of proposed system.

Imprecise perception of hand position during early motor adaptation.

Localizing one's body parts is important for movement control and motor learning. Recent studies have shown that the precision with which people localize their hand places constraints on motor adaptation. Although these studies have assumed that hand localization remains equally precise across learning, we show that precision decreases rapidly during early motor learning. In three experiments, healthy young participants (n = 92) repeatedly adapted to a 45° visuomotor rotation for a cycle of two to four reaches, followed by a cycle of two to four reaches with veridical feedback. Participants either used an aiming strategy that fully compensated for the rotation (experiment 1), or always aimed directly at the target, so that adaptation was implicit (experiment 2). We omitted visual feedback for the last reach of each cycle, after which participants localized their unseen hand. We observed an increase in the variability of angular localization errors when subjects used a strategy to counter the visuomotor rotation (experiment 1). This decrease in precision was less pronounced in the absence of reaiming (experiment 2), and when subjects knew that they would have to localize their hand on the upcoming trial, and could thus focus on hand position (experiment 3). We propose that strategic reaiming decreases the precision of perceived hand position, possibly due to attention to vision rather than proprioception. We discuss how these dynamics in precision during early motor learning could impact on motor control and shape the interplay between implicit and strategy-based motor adaptation.NEW & NOTEWORTHY Recent studies indicate that the precision with which people localize their hand limits implicit visuomotor learning. We found that localization precision is not static, but decreases early during learning. This decrease is pronounced when people apply a reaiming strategy to compensate for a visuomotor perturbation and is partly resistant to allocation of attention to the hand. We propose that these dynamics in position sense during learning may influence how implicit and strategy-based motor adaption interact.

Multi-bounce self-mixing in terahertz metasurface external-cavity lasers

The effects of optical feedback on a terahertz (THz) quantum-cascade metasurface vertical-external-cavity surface-emitting laser (QC-VECSEL) are investigated via self-mixing. A single-mode 2.80 THz QC-VECSEL operating in continuous-wave is subjected to various optical feedback conditions (i.e., feedback strength, round-trip time, and angular misalignment) while variations in its terminal voltage associated with self-mixing are monitored. Due to its large radiating aperture and near-Gaussian beam shape, we find that the QC-VECSEL is strongly susceptible to optical feedback, which is robust against misalignment of external optics. This, in addition to the use of a high-reflectance flat output coupler, results in high feedback levels associated with multiple round-trips within the external cavity-a phenomenon not typically observed for ridge-waveguide QC-lasers. Thus, a new theoretical model is established to describe self-mixing in the QC-VECSEL. The stability of the device under variable optical feedback conditions is also studied. Any mechanical instabilities of the external cavity (such as vibrations of the output coupler), are enhanced due to feedback and result in low-frequency oscillations of the terminal voltage. The work reveals how the self-mixing response differs for the QC-VECSEL architecture, informs other systems in which optical feedback is unavoidable, and paves the way for QC-VECSEL self-mixing applications.

AI- POWERED BASED BLIND AND VISUALLY IMPAIRED SYSTEM FOR SMART GLASS

Visual impairment causes serious problems in daily life and mobility for millions of people worldwide. Against this background, smart assistive technology is gaining momentum to improve the independence and quality of life of the blind and visually impaired. They have difficulty in daily life because they cannot detect the problems around them, and one of their biggest problems is identifying people. Besides automation, there are many unexplored uses of search engines. This project includes an app that uses search to help blind people see things in front of them safely, and a facial recognition system with visual feedback that can help visually impaired people see familiar and unfamiliar people. The speaker will provide them with sound support. In this work, we use deep learning-based Regional Convolutional Neural Network (Faster R-CNN) to detect and identify people and objects in the environment. Faster local convolutional neural network technology processes and distributes images captured by cameras. The operator takes the image as input. Therefore, this model helps visually impaired people in a simpler way than a white cane. Keywords—Visuallmpairment,Objectdetection,Faster Region Convolutional Neural Network.

Effect of visual feedback balance system combined with digital treadmill on gait kinematics in patients with subacute cerebral infarction.

Effect of visual feedback balance system combined with digital treadmill on gait kinematics in patients with subacute cerebral infarction.

The relationship between prescribed ratings of perceived exertion and force production in repeated isometric contractions

Ratings of perceived exertion (RPE) are frequently used to monitor and prescribe exercise intensity. However, studies examining the shape and robustness of how feelings of effort map onto objective outputs are limited and report inconsistent results. To address this, we investigated whether (1) producing isometric forces according to RPE levels reliably leads to differences in force output, (2) if feelings of effort map linearly or non-linearly onto force output, and (3) if this mapping is robust when visual feedback and social facilitation are present. In a counterbalanced repeated measures design, N = 26 participants performed isometric handgrip contractions prescribed by ten levels of the Borg CR-10 scale. They did so either with or without the availability of concurrent visual feedback regarding their force production, and in the presence or absence of another person performing the same task simultaneously. We found that subjects reliably produced different force outputs that corresponded to each RPE level. Furthermore, concurrent visual feedback led to a linearization of force output, while in the absence of feedback, the produced forces could also be described by quadratic and cubic functions. Exploratory post-hoc analyses revealed that participants perceived moderate RPE levels to be more challenging to produce. By shedding light on the dynamic nature of the mapping between RPE and objective performance, our findings provide helpful insights regarding the utility of RPE scales.

Dynamic exploration of laser linewidth compression in resonant feedback external-cavity laser

An external-cavity laser with resonant optical feedback is a common and mature method to achieve narrow linewidth lasers. Since the proposal of optical feedback in 1964, a series of studies on resonant optical feedback have been reported. Although longer feedback length leads to narrower linewidth, it also introduces coupling of environmental noise and causes instability in the laser cavity, which is detrimental to high-speed tuning of the laser wavelength. With such a challenge, current research on resonant optical feedback primarily focuses on the static results of laser linewidth compression. In order to obtain narrow linewidth high-speed tuned external-cavity lasers, further research on the laser dynamics is required to obtain dynamic tuning of narrow linewidth external-cavity lasers. In this work, we construct an external-cavity laser based on resonant optical feedback, and utilize a coherent detection method to measure the dynamic process of laser linewidth compression and wavelength tuning. Based on resonant optical feedback from the external cavity, the linewidth of the main-cavity laser can be compressed from near 100 kHz to the 100 Hz level, with the frequency noise compressed from the order of 104 to the 102 Hz2/Hz level. Since the wavelength switching process includes frequency shift process, linewidth compression process, and frequency stabilization process, etc., we first conduct a research on laser linewidth compression dynamics. In the results of linewidth compression dynamics, we discover that using a shorter fiber ring results in shorter linewidth compression time, which is advantageous for laser dynamic tuning. We subsequently carry out the laser wavelength switching process with a main-cavity switching time in milliseconds. In the wavelength switching process, while undergoing the frequency shift process of fast tuning transient laser frequency, the laser first undergoes the linewidth broadening process, then enters the main-cavity laser frequency stabilization process and undergoes the linewidth compression process at the same time. The experimental results show that the 100 m feedback fiber ring will not significantly increase the external-cavity laser wavelength switching time under the condition that linewidth compression is faster than main-cavity laser switching, while a longer fiber ring will introduce a strong noise. Our work experimentally demonstrates that shorter feedback ring lengths lead to faster compression, which provides valuable insights for the development of high-speed and high-precision tunable narrow linewidth external-cavity lasers.

Experiencing the body as play: Cultivating older adults’ exergame experiences using embodied metaphors and multimodal feedback

Physical activity (PA) is promising in increasing active life for older adults, but its repetitive and fatigue-inducing nature greatly harms older adults’ motivation to participate. Recently, there has been a growing interest in applying exergames to improve older adults’ PA adherence and engagement. To better support body-based interactions, embodied metaphors and multimodal feedback are suggested to ensure effective and meaningful mapping between elderly players’ input actions and exergame responses, but their effectiveness have not been fully investigated. After developing a list of embodied and ontological metaphors based a series of user-centered approaches, two experiments were conducted to investigate how embodied metaphors and multimodal feedback impact older adults'’ playing experience of PA exergames, among fifty-nine and twenty-five older adults, respectively. Regarding the embodied metaphor design, the results indicated that a higher embodiment level significantly and positively influenced the participants’ acceptance behavior in terms of their attitudes toward the exergame, and a higher information richness level demonstrated significantly positive effects on familiarity perception and all aspects of acceptance behavior. For the multimodal feedback design, the results indicated that 3D visual feedback better facilitated the participants’ sense of embodiment and immersion, as well as their acceptance behavior, compared to 2D visual feedback. Furthermore, constant tactile feedback in a continuous-only or continuous-and-augmented way significantly improved the participants’ PA movement performance and sense of embodiment, rather than instant feedback. Accordingly, a list of design guidelines for PA exergame development is proposed, with the possible contributions and limitations of this research addressed.

Spatio-temporal modulation of cortical activity during motor deadaptation depends on the feedback of task-related error

Motor adaptations are responsible for recalibrating actions and facilitating the achievement of goals in a constantly changing environment. Once consolidated, the decay of motor adaptation is a process affected by available sensory information during deadaptation. However, the cortical response to task error feedback during the deadaptation phase has received little attention. Here, we explored changes in brain cortical responses due to feedback of task-related error during deadaptation. Twelve healthy volunteers were recruited for the study. Right hand movement and EEG were recorded during repetitive trials of a hand reaching movement. A visuomotor rotation of 30° was introduced to induce motor adaptation. Volunteers participated in two experimental sessions organized in baseline, adaptation, and deadaptation blocks. In the deadaptation block, the visuomotor rotation was removed, and visual feedback was only provided in one session. Performance was quantified using angle end-point error, averaged speed, and movement onset time. A non-parametric spatiotemporal cluster-level permutation test was used to analyze the EEG recordings. During deadaptation, participants experienced a greater error reduction when feedback of the cursor was provided. The EEG responses showed larger activity in the left centro-frontal parietal areas during the deadaptation block when participants received feedback, as opposed to when they did not receive feedback. Centrally distributed clusters were found for the adaptation and deadaptation blocks in the absence of visual feedback. The results suggest that visual feedback of the task-related error activates cortical areas related to performance monitoring, depending on the accessible sensory information.

Video-based interventions promoting social behavioural skills for autistic children and young people: An evidence and gap map.

Video-based interventions (VBIs) are an approach that can be used to promote social behavioural skills for autistic children and young people. Despite an abundance of literature in this area, previous evidence syntheses are limited by their exclusive search strategies and eligibility criteria. Therefore, there is a lack of comprehensive evidence syntheses to provide insight on whether these interventions work, for whom, and in what circumstances. Evidence and Gap Maps (EGMs) are used to collate vast literature on a broad topic area such as this, highlighting areas for synthesis, and identifying gaps for future research. To identify, map and synthesise existing primary research on VBIs promoting social behavioural skills for autistic children and young people, creating a live, searchable and publicly available EGM. Searches were conducted in electronic databases (n = 8), web search engines, and other repositories including published papers and grey literature. The search strategy was developed around two concepts including (1) terms related to autism, and (2) terms related to VBIs. Searches were conducted in May 2021. All primary studies evaluating the effectiveness of VBIs in promoting social behaviours for autistic children and young people aged 3-18 were included in the EGM. Search results were imported into Eppi-Reviewer where duplicates of identical studies were removed. Titles and abstracts were then screened by two independent reviewers. Potentially eligible full texts were located and also screened by two reviewers. Data were then extracted on study design, participant characteristics, type of intervention, type of outcome, and country of study, by one of three reviewers. EPPI-Mapper was used to create the interactive EGM. The current EGM contains 438 studies reporting on 394 single subject research designs, 25 randomised controlled trials, 15 non-randomised group designs, and 8 pretest-posttest designs. Included studies evaluated VBIs in all male (n = 238), mixed gender (n = 172) or all female (n = 17) samples. VBIs employed included video modelling (n = 273), video self-modelling (n = 82), point-of-view modelling (n = 61), video prompting (n = 57), video feedback (n = 12) and computer-based video instruction (n = 4). The most frequently used models were adults (n = 191) and peers (n = 135). In relation to social outcomes, almost half evaluated social engagement (n = 199) with limited studies looking at safety (n = 9) and community (n = 7) skills. This EGM provides a valuable resource for policy-makers, practitioners, researchers, funders and members of the public to access evidence on VBIs promoting social behavioural skills in autistic children and young people. The map has identified areas of sufficient research where evidence can undergo synthesis. In addition, important gaps in the evidence were highlighted and suggest further research is warranted in all female samples and less frequently evaluated types of VBIs and social outcomes. Evidence included in this EGM will be further explored via systematic review and meta-analysis on control group designs.