# Upper Body Pose Estimation Using Deep Learning for a Virtual Reality Avatar
## 2 Related Works  
Some humanities scholars have begun to use the term \"presence\" (from the scientific literature on VR), defined loosely as the feeling of being there. The terms immersion and presence are increasingly seen together, although both have been so loosely defined as interchangeable--which they often are [8]. Presence induced by technology-drivenimmersion is a form of illusion because, in VR, stimuli are merely a form of energy projected onto our receptors. Examples include light from pixels on a screen or sound waves recorded at different times and places emitted from speakers [9]. Other researchers distinguish various forms of presence from unique perspectives. Presence is divided into four core components that are merely illusions of a non-existent reality. Based on our study's scope, we only discuss the illusion of self-embodiment and the illusion of social communication. Self-embodiment is the perception that the user has a body within the virtual world. Presence is greatly strengthened and experienced more deeply if a user sees a visual object touching the skin while a physical object also touches the skin [10]. [PERSON] et al. [11] prove that an illusion of embodiment intensifies the emotional processing of the virtual environment. Even if the VR body does not look similar to one's own body, the presence of a virtual body can be compelling. In contrast to physical attributes such as body shape and color, the importance of motion cannot be overstated. A discrepancy between visual body motion and actual physical activity can result in a breakdown of presence. Social presence refers to the sense that a user is genuinely communicating, both verbally and through nonverbal cues such as body language, with other entities in the same environment, whether they be computer-controlled or operated by other users. Physical realism is not a prerequisite to social realism. Users have been found to express anxiety when they cause pain to low-fidelity virtual characters [12], and when users with a fear of public speaking must talk in front of a low-fidelity virtual audience [13]. While the level of social presence can increase as the realism of human behavior and objects (referred to as behavioral realism) improves, the mere tracking and rendering of a few key points on human users can effectively create a compelling experience [14]. Most of the research on the presence of VR uses expensive motion capture systems [15; 16]. Consumer-grade depth sensors such as a Kinect detect body tracking [17], but do not provide the necessary accuracy. A Kinect v1.0 is limited: a low-resolution RGB-depth camera with a 320 \(\times\) 240 16-bit depth sensor and a 640 \(\times\) 480 32-bit color sensor, at a capture rate of 30 Hz. This low spatial and temporal resolution favors interactive gaming experiences over accurate pose reconstruction, resulting in the loss of crucial information for faster motion. A Kinect v1.0 device also limits the capture space to a small region of approximately two square meters [18]. [PERSON] et al. [19] demonstrate that incorrect poses could decrease embodiment, suggesting that it might be more helpful not to display limbs if their poses are not sufficiently accurate. Consequently, the proposed method must obtain an accurate position to create a true sense of embodiment for a VR user. This study uses a data-driven solver method to predict upper body poses by integrating pose estimation in VR. Some companies combine IK with VR, which can animate 3D characters of any shape or size in real time. Studies present an entire body using IK without running a user study to evaluate embodiment [20; 21]. The result can be a virtual avatar that responds with natural movements, creating a stronger sense of VR immersion. However, many iterations are mandatory before converging on a solution that may ultimately generate improper joint orientations [22]. Nonetheless, the evidence for this is inconclusive. Researchers have introduced deep learning methods to estimate human body poses. [PERSON] et al.