With the recent development of a digital rehabilitation system, research on the rehabilitation of amputees is accelerating. However, research on rehabilitation systems for patients with amputation of the lower extremities is insufficient. For the rehabilitation of amputees, it is important to maintain muscle mass through the improvement of muscle movement memory, continuous rehabilitation learning, and motivation to improve efficiency. The rehabilitation system in a virtual environment is convenient in that there is no restriction on time and space because rehabilitation training of amputees is possible without removing/attaching general prosthetic legs and robot prosthetic legs. In this paper, we propose an XR rehabilitation system for patients with lower extremity amputation to improve the motivational aspect of rehabilitation training. The proposed method is a system that allows patients and clinical experts to perform rehabilitation in the same environment using two XR equipment called HoloLens 2. The content was provided in the form of a game in which the number of movements of amputees was allocated as scores to enhance rehabilitation convenience and motivation aspects. The virtual 3D model prosthetic leg used in-game content worked through the acquisition and processing of the patient’s actual muscle EMG (ElectroMyoGraphy) signal. In order to improve reactivity, there was a time limit for completing the operation. The classified action should be completed by the amputee within the time limit, although the number of times set as the target. To complete the operation, the amputee must force the amputation area to exceed an arbitrarily set threshold. The evaluation results were evaluated through an independent sample t-test. we contribute to the development of digital rehabilitation simulation systems. XR rehabilitation training techniques, operated with EMG signals obtained from actual amputation sites, contribute to the promotion of rehabilitation content in patients with amputation of the lower extremities. It is expected that this paper will improve the convenience and rehabilitation of rehabilitation training in the future.

Recently, the development of 3D graphics technology has led to various technologies being combined with reality, where a new reality is defined or studied; they are typically named by combining the name of the technology with “reality”. Representative “reality” includes Augmented Reality, Virtual Reality, Mixed Reality, and eXtended Reality (XR). In particular, research on XR in the web environment is actively being conducted. The Web eXtended Reality Device Application Programming Interface (WebXR Device API), released in 2018, allows instant deployment of XR services to any XR platform requiring only an active web browser. However, the currently released tentative version has poor stability. Therefore, in this study, the performance evaluation of WebXR Device API is performed using three experiments. A camera trajectory experiment is analyzed using ground truth, we checked the standard deviation between the ground truth and WebXR for the X, Y, and Z axes. The difference image experiment is conducted for the front, left, and right directions, which resulted in a visible difference image for each image of ground truth and WebXR, small mean absolute error, and high match rate. In the experiment for measuring the 3D rendering speed, a frame rate similar to that of real-time is obtained.