scholarly journals Size Perception Bias and Reach-to-Grasp Kinematics: An Exploratory Study on the Virtual Hand With a Consumer Immersive Virtual-Reality Device

2021 ◽  
Vol 2 ◽  
Author(s):  
Yoshihiro Itaguchi
Keyword(s):  
Virtual Reality ◽  
Tactile Feedback ◽  
Size Perception ◽  
Psychophysical Method ◽  
Immersive Virtual Reality ◽  
Reach To Grasp ◽  
Psychological Phenomena ◽  
Virtual Hand ◽  
Everyday Object ◽  
Perception Bias

While studies have increasingly used virtual hands and objects in virtual environments to investigate various processes of psychological phenomena, conflicting findings have been reported even at the most basic level of perception and action. To reconcile this situation, the present study aimed 1) to assess biases in size perception of a virtual hand using a strict psychophysical method and 2) to provide firm and conclusive evidence of the kinematic characteristics of reach-to-grasp movements with various virtual effectors (whole hand or fingertips only, with or without tactile feedback of a target object). Experiments were conducted using a consumer immersive virtual reality device. In a size judgment task, participants judged whether a presented virtual hand or an everyday object was larger than the remembered size. The results showed the same amplitude of underestimation (approximately 5%) for the virtual hand and the object, and no influence of object location, visuo-proprioceptive congruency, or short-term experience of controlling the virtual hand. Furthermore, there was a moderate positive correlation between actual hand size and perception bias. Analyses of reach-to-grasp movements revealed longer movement times and larger maximum grip aperture (MGA) for a virtual, as opposed to a physical, environment, but the MGA did not change when grasping was performed without tactile feedback. The MGA appeared earlier in the time course of grasping movements in all virtual reality conditions, regardless of the type of virtual effector. These findings confirm and corroborate previous evidence and may contribute to the field of virtual hand interfaces for interactions with virtual worlds.

scholarly journals DeepHandsVR: Hand Interface Using Deep Learning in Immersive Virtual Reality

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1863 ◽  
Author(s):  
Taeseok Kang ◽  
Minsu Chae ◽  
Eunbin Seo ◽  
Mingyu Kim ◽  
Jinmo Kim
Keyword(s):  
Virtual Reality ◽  
Deep Learning ◽  
User Satisfaction ◽  
Simple Structure ◽  
Hand Gesture ◽  
Immersive Virtual Reality ◽  
Positive Effects ◽  
Virtual Hand ◽  
Sense Of Presence ◽  
Deep Learning Model

This paper proposes a hand interface through a novel deep learning that provides easy and realistic interactions with hands in immersive virtual reality. The proposed interface is designed to provide a real-to-virtual direct hand interface using a controller to map a real hand gesture to a virtual hand in an easy and simple structure. In addition, a gesture-to-action interface that expresses the process of gesture to action in real-time without the necessity of a graphical user interface (GUI) used in existing interactive applications is proposed. This interface uses the method of applying image classification training process of capturing a 3D virtual hand gesture model as a 2D image using a deep learning model, convolutional neural network (CNN). The key objective of this process is to provide users with intuitive and realistic interactions that feature convenient operation in immersive virtual reality. To achieve this, an application that can compare and analyze the proposed interface and the existing GUI was developed. Next, a survey experiment was conducted to statistically analyze and evaluate the positive effects on the sense of presence through user satisfaction with the interface experience.

scholarly journals Error, rather than its probability, elicits specific electrocortical signatures: a combined EEG-immersive virtual reality study of action observation

2018 ◽  
Vol 120 (3) ◽  
pp. 1107-1118 ◽  
Author(s):  
Rachele Pezzetta ◽  
Valentina Nicolardi ◽  
Emmanuele Tidoni ◽  
Salvatore Maria Aglioti
Keyword(s):  
Virtual Reality ◽  
Monitoring System ◽  
Performance Monitoring ◽  
Action Observation ◽  
Orienting Response ◽  
Immersive Virtual Reality ◽  
Reach To Grasp ◽  
Cave System ◽  
Person Perspective ◽  
Salient Event

Detecting errors in one’s own actions, and in the actions of others, is a crucial ability for adaptable and flexible behavior. Studies show that specific EEG signatures underpin the monitoring of observed erroneous actions (error-related negativity, error positivity, mid-frontal theta oscillations). However, the majority of studies on action observation used sequences of trials where erroneous actions were less frequent than correct actions. Therefore, it was not possible to disentangle whether the activation of the performance monitoring system was due to an error, as a violation of the intended goal, or to a surprise/novelty effect, associated with a rare and unexpected event. Combining EEG and immersive virtual reality (IVR-CAVE system), we recorded the neural signal of 25 young adults who observed, in first-person perspective, simple reach-to-grasp actions performed by an avatar aiming for a glass. Importantly, the proportion of erroneous actions was higher than correct actions. Results showed that the observation of erroneous actions elicits the typical electrocortical signatures of error monitoring, and therefore the violation of the action goal is still perceived as a salient event. The observation of correct actions elicited stronger alpha suppression. This confirmed the role of the alpha-frequency band in the general orienting response to novel and infrequent stimuli. Our data provide novel evidence that an observed goal error (the action slip) triggers the activity of the performance-monitoring system even when erroneous actions, which are, typically, relevant events, occur more often than correct actions and thus are not salient because of their rarity. NEW & NOTEWORTHY Activation of the performance-monitoring system (PMS) is typically investigated when errors in a sequence are comparatively rare. However, whether the PMS is activated by errors per se or by their infrequency is not known. Combining EEG-virtual reality techniques, we found that observing frequent (70%) action errors performed by avatars elicits electrocortical error signatures suggesting that deviation from the prediction of how learned actions should correctly deploy, rather than its frequency, is coded in the PMS.

scholarly journals Heat pain modulation with virtual water during a virtual hand illusion

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ivo Käthner ◽  
Thomas Bader ◽  
Paul Pauli
Keyword(s):  
Virtual Reality ◽  
Thermal Sensation ◽  
Red Light ◽  
Light Condition ◽  
Virtual Water ◽  
Pain Modulation ◽  
Sense Of Agency ◽  
Immersive Virtual Reality ◽  
Experimental Conditions ◽  
Virtual Hand

AbstractImmersive virtual reality is a powerful method to modify the environment and thereby influence experience. The present study used a virtual hand illusion and context manipulation in immersive virtual reality to examine top-down modulation of pain. Participants received painful heat stimuli on their forearm and placed an embodied virtual hand (co-located with their real one) under a virtual water tap, which dispensed virtual water under different experimental conditions. We aimed to induce a temperature illusion by a red, blue or white light suggesting warm, cold or no virtual water. In addition, the sense of agency was manipulated by allowing participants to have high or low control over the virtual hand’s movements. Most participants experienced a thermal sensation in response to the virtual water and associated the blue and red light with cool/cold or warm/hot temperatures, respectively. Importantly, the blue light condition reduced and the red light condition increased pain intensity and unpleasantness, both compared to the control condition. The control manipulation influenced the sense of agency, but did not influence pain ratings. The large effects revealed in our study suggest that context effects within an embodied setting in an immersive virtual environment should be considered within VR based pain therapy.

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