Field of View: Evaluation of Oculus Rift and HTC Vive Purpose Objective To determine how Head-Mounted Displays (HMDs), such as the Oculus To determine the true horizontal and vertical Field of View (FOV) Rift and HTC Vive, can influence highly immersive training environments, capabilities of the Oculus Rift and HTC Vive HMDs; and to compare the by interpreting empirically-driven data gathered through software true FOV between the two HMDs, as well as each HMD’s true and testing. respective marketed FOV values. . Procedure The experimental evaluation, including the participant’s role (Figure 1), is below. Step 1

Step 1: Participant looks at displayed target (T) to sync view. Step 2: Participant turns head horizontally left, then repeats Step 1. Step 3: Participant turns head horizontally right, then repeats Step 1. Step 4: Participant turns head vertically up, then repeats Step 1. Step 5: Participant turns head vertically down, then repeats Step 1. Step 6: The degrees the participant moved in each direction is recorded in a spreadsheet (Figure 2). Step 7: True FOV, and thus the visual display area of the devices, is calculated (Figure 3). Figure 1: Participant’s Role (phr00t, 2016)

Figure 2: FOV Experiment Result Spreadsheet

Figure 3: HMD Visual Display Area (Yoo, 2017) Results Device FOV Component Marketed Value Experiment Result (True FOV) Oculus Rift Horizontal 110° 93° Oculus Rift Vertical 110° 101° HTC Vive Horizontal 110° 112° HTC Vive Vertical 110° 116° Conclusion • The Oculus Rift FOV is smaller than its marketed value, whereas the HTC Vive FOV is slightly larger. The results suggest that the HTC Vive has larger FOV capabilities, more closely resembling a binocular human eye FOV (i.e., 200° horizontal x 120° vertical). • The data can be used to judge which HMD would be adequate in a live or simulated training session, dependent on the session itself. For example, virtual on-foot training would require a FOV closely related to the human eyes’ FOV, whereas a military vehicle simulation may require only a limited FOV (Baltzer et al., 2015). • The next step is to integrate other HMDs (e.g., the HTC Vive Pro, FOVE, and HoloLens) into the experiment procedure to determine the other HMDs’ true FOVs. References Baltzer, M. C., Krasni, A., Boehmsdorff, P., Linder, T., Heesen, M., & Flemisch, F. (2015). Towards virtually transparent vehicles: first results of a simulator study and a field trial. In AVT-256 Specialists’ Meeting on Augmented Reality for Improved Situational Awareness and Survivability of Combat Vehicles, NATO STO, Prague. phr00t (2016). Hmd-fov-tester (Version 1.0) [Source code]. Available from https://github.com/phr00t/hmd-fov-tester Yoo, K.H. (2017). HMD based VR Service Framework [PDF document]. Retrieved from http://www.web3d.org/sites/default/files/page/Korea%20Chapter%20Meeting%20SIGGRAPH%202017/4_hmd-vr-service-framework_20170731.pdf