Performance Evaluation of the Low-Cost Virtual Reality System for Real-Time Visualization of Underwater Environments

Underwater operations involve many dangers. Recently, the use of robots has been progressed to improve safety. In such situations, it is important to have a means to better understand the robot's situation. However, to put it to practical use, it is necessary not only to improve performance but also to consider cost. This paper proposes a low-cost system that enables real-time underwater video acquisition using a 360°camera and a head-mounted display (HMD), and evaluates whether the performance is sufficient for practical use. In this system, a 360° camera is mounted on the robot within communication range, and real-time images are transmitted to the HMD via a host computer. Experiments were conducted using actual equipment, both in the tank and at sea. The system was also evaluated based on the delay and image quality during these experiments. The delay depends on the amount of data in the packets sent to the HMD in a single communication. Therefore, experiments were conducted for each combination of several data sizes and two HMDs with different performance. As for image quality, a weight was placed in the tank and the visibility of the two HMDs at different distances was compared. Based on these experiments, it was found that this system can be operated with a level of delay that is acceptable for use and that the image quality, which leads to ease of use, depends only on the resolution of the camera.