A Walking-in-Place Method for Virtual Reality Using Position and Orientation Tracking

Abstract

People are interested in traveling in an infinite virtual environment, but no standard navigation method exists yet in Virtual Reality (VR). The Walking-In-Place (WIP) technique is a navigation method that simulates movement to enable immersive travel with less simulator sickness in VR. However, attaching the sensor to the body is troublesome. A previously introduced method that performed WIP using an Inertial Measurement Unit (IMU) helped address this problem. That method does not require placement of additional sensors on the body. That study proved, through evaluation, the acceptable performance of WIP. However, this method has limitations, including a high step-recognition rate when the user does various body motions within the tracking area. Previous works also did not evaluate WIP step recognition accuracy. In this paper, we propose a novel WIP method using position and orientation tracking, which are provided in the most PC-based VR HMDs. Our method also does not require additional sensors on the body and is more stable than the IMU-based method for non-WIP motions. We evaluated our method with nine subjects and found that the WIP step accuracy was 99.32% regardless of head tilt, and the error rate was 0% for squat motion, which is a motion prone to error. We distinguish jog-in-place as “intentional motion” and others as “unintentional motion”. This shows that our method correctly recognizes only jog-in-place. We also apply the saw-tooth function virtual velocity to our method in a mathematical way. Natural navigation is possible when the virtual velocity approach is applied to the WIP method. Our method is useful for various applications which requires jogging.

Walking with head-mounted virtual and augmented reality devices: Effects on position control and gait biomechanics

“…The large CoP area and boundaries suggest that the use of an HMD on a conventional treadmill may be rather dangerous if guidance on position is unavailable, and therefore, hardware and software enhancement might be necessary. Solutions like using IMU-based position and orientation tracking [51] or an omni-directional treadmill (Indinadeck, Rocklin, California, USA) might help to tackle the problem of using a similar HMD device as used in the current study within a clinical setting. Another potential solution could be adopting a computer-generated optic flow [8] that matches with the treadmill speed, which could help improve the congruency between the users’ proprioceptive sensory information and the visual feedback provided in the VR devices.…”

Literature review of locomotion techniques in virtual reality

“…Some studies tried to solve these problems by using other parameters to detect the walking like the position and orientation of the head mounted display (see Figure 4). Moreover the immersion level of the user is still low (Lee et al, 2018;Nilsson et al, 2013). In addition, standing position is not always appropriate to explore the virtual environment.…”

“…Over the last ten years, technological progress has significantly improved user experience in the virtual world. Despite the fact that locomotion is not the primary objective of virtual reality applications, it is considered to be one of the most important components of interaction in virtual reality experiences because it is indispensable and crucial to explore the virtual environment (Lee et al, 2018). The emergence of new virtual reality devices like the commercial releases of the HTC Vive and the Oculus Rift, marked the beginning of what some researchers call "a new era in the history of virtual reality".…”

The effect of water immersion on vection in virtual reality

“…To do so, they have investigated ways for the users to be physically active during exploration of a large virtual environment while preventing large displacement in the physical world. These strategies included walking in place 45 , 46 , stepping in place in a human-size hamster ball 47 , or walking on a directional treadmill 48 , 49 or multidirectional surface made of tiles moving in the opposite direction of the user 50 . Another strategy, called redirected walking, consists of curving the walking trajectory through visual rotation of the virtual environment without being noticed by the users 51 , 52 allowing them to explore a large virtual area while walking only in a limited space.…”