# Real-Time Interaction for 3D Pixel Human in Virtual Environment
## 5 Experiments and Results
### Usability Experiment  
Our second experiment aimed to verify the usability of the proposed method and used the same equipment and virtual meeting room scene as the first experiment. In addition to interacting with virtual objects in the same manner as in the first experiment, the second experiment also allowed participants to perform some common arm movements, such as hand waving, during online conferences and generates their pixel avatars in real-time, showing their appearance from their own perspective and other people's perspectives,respectively. We asked users to comprehensively evaluate the performance of our method in virtual meetings and virtual object interaction and complete the system usability scale (SUS) questionnaire [44] to evaluate the usability of our method. The SUS questionnaire is widely used for interface evaluation and contains 10 items on a 5-point scale (1 to 5 points). As shown in Figure 11, the SUS score of our method is 88.28, which is much higher than the average score of 68 on the SUS questionnaire, indicating excellent feedback. From these results, we can conclude that our system is easy to understand and use, and can help users better complete tasks, such as virtual object interactions in a virtual environment.  
Additionally, we conducted an experiment to evaluate the performance of the proposed avatar. The results demonstrate that our method can generate pixel avatars of various resolutions (see Figure 12). Additionally, we recorded the FPS of the avatars of different resolutions during a virtual meeting. The results reveal that we can generate a 320 \(\times\) 240 resolution pixel avatar at 12 FPS, 160 \(\times\) 120 resolution pixel avatar at 19 FPS, 80 \(\times\) 60 resolution pixel avatar at 20 FPS, and 40 \(\times\) 30 resolution pixel avatar at 20 FPS. While generating the images of head and body and pose data required by the pixel avatar in the human video stream processing stage, the time required for the 320 \(\times\) 240 resolution pixel avatar is 40 ms, the time required for the 160 \(\times\) 120 resolution pixel avatar is 38 ms, the time required for the 80 \(\times\) 60 resolution is 38 ms, and the time required for 40 \(\times\) 30 resolution pixel avatar is 37 ms. From left to right, the avatar resolutions range from high to low. The low-resolution results reflect the artistic pixel style, whereas the high-resolution results are closer to real people and have a sense of realism. We investigated participant preferences regarding the resolution of the generated avatars. More than 93% (15 of all 16 participants) of the participants chose the highest 320 \(\times\) 240 resolution pixel avatar because it can represent more body features and details, and the higher-resolution pixel body is more consistent with the high-resolution head video stream.  
Figure 11: SUS score results for the proposed pixel avatar method.  
Figure 12: Pixel avatars with different resolutions: (**a**) 320 \(\times\) 240 resolution pixel avatar; (**b**) 160 \(\times\) 120 resolution pixel avatar; (**c**) 80 \(\times\) 60 resolution pixel avatar; (**d**) 40 \(\times\) 30 resolution pixel avatar.