# Motion Sickness in Mixed-Reality Situational Awareness System
## 2 Related Work  
The field of VR has undergone significant development, transitioning from its initial phase of exploration to a rapidly growing domain with diverse applications in areas such as entertainment, education, and medical rehabilitation. Despite the promising potential of VR, a significant obstacle to its widespread adoption is the occurrence of motion sickness caused by virtual environments [8; 9; 10; 11; 12; 13; 14; 15]. The purpose of this Section is to provide a comprehensive analysis of the causes, measurement techniques, and potential solutions for motion sickness induced by VR. This will be achieved by reviewing and analyzing the current body of literature on the topic. Full 360-degree VR videos and the time consistency of stitching the scene has been shown to cause MS [16]. Several methods have already been proposed to alleviate MS in these cases but not all of them have been thoroughly researched. [PERSON] et al. [2] suggest a VR environment should be treated as a theater and not a film; this means camera animations and tricks like involuntary zooming and a lack of a reference can have a massive impact on comfort in VR. A virtual body, on the other hand, has been shown to have a negative impact on motion sickness [17]. [PERSON] et al. [18] proposed motion parallax to help with MS, but this may not counteract the MS caused by frame delay due to its added computational cost. The article by [PERSON] et al. [4] provides a significant and influential contribution by presenting a thorough classification system that categorizes the origins of motion sickness induced by VR. The taxonomy identifies three primary domains that contribute to VR-induced motion sickness: hardware-related factors, content-related attributes, and individual-specific human variables. Hardware factors encompass various technical specifications, including display technology, Field of View (FoV) range, latency, and flicker rate. From a content standpoint, various complex factors, such as the dynamics of optical flow, the fidelity of graphical rendering, and the contextually optimized dimensions of the FoV, are identified as crucial precursors. The field of human factors encompasses demographic factors, such as age and gender, as well as experiential factors, with a particular focus on an individual's inherent vulnerability to motion sickness. [PERSON] emphasizes the importance of reducing the discrepancy between visual and vestibular cues as a crucial approach to alleviate motion sickness [19]. The importance of controlling translational and rotational velocities, adopting HMDs with wide fields of view, and avoiding obstructions in the central visual field is supported by the empirical evidence presented in this study. In their research work, [PERSON] et al. [20] provide significant contributions to the field. Their argument suggests that the use of windscreen projection, which offers a wider field of view both horizontally (40 degrees) and vertically (35 degrees), leads to a reduced likelihood of causing simulator sickness when compared to traditional HMDs. Modifications to the design of virtual reality content in order to address the issue of motion sickness were proposed by [PERSON] et al. [2]. The advised methodology promotes the conceptualization of VR experiences in a manner similar to theatrical productions. This involves incorporating static frame references and avoiding involuntary camera movements. These measures collectively contribute to the enhancement of user immersion and the reduction of discomfort. The study by [PERSON] et al. [21] presents a unique approach that utilizes a distortion technique to align user expectations with the motion experienced in a vehicle, resulting in a decrease in motion sickness. [PERSON] et al. [22] present an innovative approach that involves modulating the field of view in order to effectively alleviate symptoms of motion sickness.