Projection mapping (PM) is attractive as a fundamental technology for the advancement of various subjects, such as media art, entertainment, and augmented reality. However, conventional projectors have a shallow depth of field (DOF); therefore, sharp images are only visible in the limited depth range. In the case of dynamic projection mapping (DPM), which can project images on the surface of the moving objects, the shallow DOF limits the permissible motion of the object, because the projected images become blurred when the object is outside the DOF.
Our laboratories have developed a high-speed focal tracking projection system, which includes the technologies of high-speed vision, high-speed projector, and high-speed variable focus optics. In this system, the variation of the object's distance and posture was captured using the high-speed vision technology that served as immediate feedback to the liquid lens and high-speed projector. As a result, the focal distance is compensated, and the projected images are updated in real-time to fit the moving object. Therefore, a well-focused image projection was achieved even when the motion involved large depth range movement.
This system could ensure that the projected images were sharp and clear at variable distances, while the object was moving dynamically in a large three-dimensional area. Hence, this approach can be effectively applied to applications such as Volume Slicing Display. Furthermore, it can turn any physical surface into an interactive display, and enable the manipulation of their appearance to provide detailed information. Our system provides the essential technology for expanding such applications.
This work is the result of collaborative research between Ishikawa Group Laboratory (University of Tokyo), Watanabe Laboratory (Tokyo Institute of Technology), and Wang Laboratory (Institute of Semiconductor, Guangdong Academy of Sciences, China).
References
- Lihui Wang, Satoshi Tabata, Hongjin Xu, Yunpu Hu, Yoshihiro Watanabe, and Masatoshi Ishikawa: Dynamic depth-of-field projection mapping method based on a variable focus lens and visual feedback, Optics Express, Vol. 31, No. 3, pp. 3945-3953 (2023)
- Lihui Wang, Hongjin Xu, Satoshi Tabata, Yunpu Hu, Yoshihiro Watanabe, and Masatoshi Ishikawa: High-Speed Focal Tracking Projection Based on Liquid Lens, SIGGRAPH Emerging Technologies, 2020.