Identifying and mitigating the cognitive implications of semi-natural virtual locomotion techniques

Users of virtual reality systems often need to navigate to distant parts of the virtual environment in order to perform their desired tasks. Unfortunately, physical space restrictions as well as tracker range limitations preclude the use of fully natural techniques for navigation through an infinite virtual environment. This necessitates the use of a locomotion interface, and the closer that interface matches the analogous real world actions, the easier it will be for the user. Unnatural techniques require cognitive effort on the part of the users. Many authors have attempted to address this problem by creating locomotion interfaces and techniques that more closely approximate real world counterparts to the extent possible. In addition to requiring these unnatural movements, current virtual reality systems are incapable of providing the high-fidelity sensory feedback used to guide real-world movements. This may cause users to resort to more cognitively demanding strategies. There is a large body of research in the psychology domain regarding the structure of cognitive resources. In particular, Baddeley\u27s multi-component model of working memory describes a separation between the resources used for verbal and non-verbal storage and processing. It is likely that semi-natural locomotion techniques require some of these resources, which will then be unavailable for concurrent tasks. A pair of studies was conducted, investigating the cognitive resource requirements of several atomic locomotion movements by manipulating the user interface and field of view. The results indicate that semi-natural locomotion interfaces generally require a user\u27s spatial cognitive resources. Based on the conclusions from the working memory studies, an adaptive system was designed that can learn how to adjust parameters of the locomotion technique according to a user\u27s present cognitive task load

First-person locomotion in 3D virtual environments: a usability analysis

3D Virtual Environments (VE) are becoming popular as a tool for cognitive, functional and psychological assessment. Navigation in these environments is recognized as one of the most difficult activities in 3D Virtual Environments (VE). Users unfamiliar to 3D games, specially elder persons, get puzzled when they try to virtually move an avatar through these environments. Their inability to navigate prevents them from concentrating in the task and even to finish it. In this paper, we analyze the influence of different factors in locomotion control. We investigate the impact of having the cursor fixed at the camera center or leaving it free inside the current view. We also analyze the influence of the pitch angle on the camera control. In addition, we have designed an automatic locomotion system that we compare to user-controlled locomotion. We describe a virtual scenario and a test task that we have implemented to evaluate these different methods with users of diverse profiles.Postprint (published version

Cognitive Demands of Semi-Natural Virtual Locomotion

There is currently no fully natural, general-purpose locomotion interface. Instead, interfaces such as gamepads or treadmills are required to explore large virtual environments (VEs). Furthermore, sensory feedback that would normally be used in real-world movement is often restricted in VR due to constraints such as reduced field of view (FOV). Accommodating these limitations with locomotion interfaces afforded by most virtual reality (VR) systems may induce cognitive demands on the user that are unrelated to the primary task to be performed in the VE. Users of VR systems often have many competing task demands, and additional cognitive demands during locomotion must compete for finite resources. Two studies were previously reported investigating the working memory demands imposed by semi-natural locomotion interfaces (Study 1) and reduced sensory feedback (Study 2). This paper expands on the previously reported results and adds discussion linking the two studies. The results indicated that locomotion with a less natural interface increases spatial working memory demands, and that locomotion with a lower FOV increases general attentional demands. These findings are discussed in terms of their practical implications for selection of locomotion interfaces when designing VEs

Development of a speed protector to optimize user experience in 3D virtual environments

Virtual walking in virtual environments (VEs) requires locomotion interfaces, especially when the available physical environment is smaller than the virtual space due to virtual reality facilities limitations; many navigation approaches have been proposed according to different input conditions, target selection and speed selection. With current technologies, the virtual locomotion speed for most VR systems relies primarily on rate-control devices (e.g., joystick). The user has to manage manual adaptation of the speed, based on the size of the VE and personal preferences. However, this method cannot provide optimal speeds for locomotion as the user tends to change the speed involuntarily due to non-desired issues including collisions or simulator sickness; in this case, the user may have to adjust the speed frequently and unsmoothly, worsening the situation. Therefore, we designed a motion protector that can be embedded into the locomotion system to provide optimal speed profiles. The optimization process aims at minimizing the total jerk when the user translates from an initial position to a target, which is a common rule of the human motion model. In addition to minimization, we put constraints on speed, acceleration and jerk so that they do not exceed specific thresholds. The speed protector is formulated mathematically and solved analytically in order to provide a smooth navigation experience with a minimum jerk of trajectory. The assessment of the speed protector was conducted in a user study measuring user experience with a simulator sickness questionnaire, event-related skin conductance responses (ER-SCR), and a NASA-TLX questionnaire, showing that the designed speed protector can provide more natural and comfortable user experience with appropriate acceleration and jerk as it avoids abrupt speed profiles.China Scholarship Council: No. 20170839001

Interacción Natural Basada en un Conjunto Mínimo de Sensores Inerciales para Realidad Virtual sin Cables

La Realidad Virtual tiene un enorme potencial aún por explotar. Esta tesis doctoral pretende ir un paso más allá en el desarrollo de sistemas de Realidad Virtual inmersivos. En concreto, su objetivo fundamental es diseñar, desarrollar y evaluar una plataforma experimental sin cables para investigación en Realidad Virtual inmersiva con navegación natural e interacción manual basada en un conjunto mínimo de sensores inerciales. Para ello se emplea metodología científica desde la perspectiva de la interacción persona computador (Human Computer Interaction, HCI). A partir del objetivo fundamental, se elaboran las recomendaciones de diseño y especificaciones del sistema a desarrollar. Tras revisar en detalle el estado del arte y establecer el planteamiento metodológico, comienza el desarrollo de herramientas en las que se basará la creación de prototipos. Durante la tesis doctoral se desarrollan 3 herramientas de investigación y 5 prototipos que se evalúan a través de diversas pruebas con usuarios y 2 experimentos. En total, participan generosamente más de 85 personas. El desarrollo de prototipos da lugar a técnicas específicas que resultan de interés por sí mismas para la comunidad científica. Por otra parte, los experimentos también aportan resultados susceptibles de ser divulgados. Uno de los experimentos realizados permite evaluar las técnicas desarrolladas para implementar un sistema de Realidad Virtual con navegación natural. El otro experimento, estudia el comportamiento del sistema de tracking para interacción manual desarrollado durante el proyecto de investigación. Además, utiliza una televisión 3D y el casco de Realidad Virtual Oculus Rift para realizar un estudio comparativo de diversos aspectos como el rendimiento, usabilidad, nivel de presencia, dificultad y preferencia. El proyecto de investigación asociado a esta tesis doctoral da lugar a varias aportaciones de distinta naturaleza como publicaciones científicas, herramientas de investigación, algoritmos y trazas de datos, además de la propia plataforma experimental que permitirá abordar nuevos estudios de Realidad Virtual inmersiva con navegación natural e interacción manual

Identifying and mitigating the cognitive implications of semi-natural virtual locomotion techniques

Users of virtual reality systems often need to navigate to distant parts of the virtual environment in order to perform their desired tasks. Unfortunately, physical space restrictions as well as tracker range limitations preclude the use of fully natural techniques for navigation through an infinite virtual environment. This necessitates the use of a locomotion interface, and the closer that interface matches the analogous real world actions, the easier it will be for the user. Unnatural techniques require cognitive effort on the part of the users. Many authors have attempted to address this problem by creating locomotion interfaces and techniques that more closely approximate real world counterparts to the extent possible. In addition to requiring these unnatural movements, current virtual reality systems are incapable of providing the high-fidelity sensory feedback used to guide real-world movements. This may cause users to resort to more cognitively demanding strategies. There is a large body of research in the psychology domain regarding the structure of cognitive resources. In particular, Baddeley's multi-component model of working memory describes a separation between the resources used for verbal and non-verbal storage and processing. It is likely that semi-natural locomotion techniques require some of these resources, which will then be unavailable for concurrent tasks. A pair of studies was conducted, investigating the cognitive resource requirements of several atomic locomotion movements by manipulating the user interface and field of view. The results indicate that semi-natural locomotion interfaces generally require a user's spatial cognitive resources. Based on the conclusions from the working memory studies, an adaptive system was designed that can learn how to adjust parameters of the locomotion technique according to a user's present cognitive task load.</p