# A Novel Real-Time Virtual 3D Object Composition Method for 360\({}^{\circ}\) Video
## 5 Conclusions  
In this paper we proposed a real-time 3D composition method for 360\({}^{\circ}\) video production. The proposed system consists of two subsystems. Firstly, a stereo-vision ZED is used to obtain the parameters of the external cameras, which are mounted together to estimate the camera trajectory in real-time. Secondly, an efficient pre-visualization system is implemented to preview the results of the 3D composition during the recording.  
In this study, we exploited a system that overcomes the limitations of the traditional method, which uses camera tracking after video recording. Our experimental results show that the 3D composition results of the proposed system are not significantly different than the results obtained using the traditional method. In addition, we implemented a stable trajectory by applying a Kalman filter to the raw data obtained from the ZED. The Kalman filter achieved better trajectory results than the raw data. Our system has an advantage over the traditional method because it does not need to extract feature points from the captured images. It can save the data of the external parameters during the recording process, and this was also verified in the composition results. However, as a limitation of the proposed system, it works using a USB port and not a network. In the future, the authors plan to implement a network communication system by installing a network device that will be able to send video and transformed data to a PC for further processing.  
It can be predicted that, with the advancement of the virtual reality industry, interest in the 3D composition of 360\({}^{\circ}\) video will also increase, and therefore a more efficient system will be required. We expect that the system presented herein will be applicable for the effective 360\({}^{\circ}\) video production of 3D composition in low-budget production companies.  
**Author Contributions:** Conceptualization, J.L.; methodology, J.L., P.G.; software, J.L.; validation, J.L., L.H., and S.K.; formal analysis, J.L. and S.H.; investigation, J.L.; resources, S.K., S.H. and S.L.; data curation, J.L., P.G. and L.H.; writing--original draft preparation, J.L. and L.H.; writing--review and editing, S.K., S.H. and S.L.; visualization, J.L., L.H. and P.G.; supervision, S.K. and S.H.; project administration, S.L., P.G.; funding acquisition, S.L., S.H., and S.K. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Acknowledgments:** This research was supported by the Ministry of Science and ICT (MSIT), Korea, under the Information Technology Research Center (ITRC) support program (IITP-2020-2015-0-00448) & (IITP-2020-01846) supervised by the Institute of Information & Communications, Technology, Planning, & Evaluation (IITP). This research was supported by Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government (MSIT) (No.2020-0-00922, Development of holographic stereogram printing technology based on multi-view imaging).  
**Conflicts of Interest:** The authors declare that they have no conflict of interest.  
Figure 10: Rendered images and final 3D compositing images: (**a**,**b**) indoor and (**c**,**d**) outdoor.