# Full-Parallax Multiview Generation with High-Speed Wide-Angle Dual-Axis Scanning Optics
## 5 Experimental Results  
The high-speed wide-angle dual-axis scanner is applied to a full-parallax multiview display with spherical symmetry, as shown in Figure 12. The system structure and the prototype implementation are depicted in Figure 12a,b, respectively. We used the 3D rendering software, Rhino 6 (McNeel), to design optical mounts. The light engine, which consists of three DMDDs, each modulating red, green, or blue images, was used for high-speed projection of full-color images [28]. The V-7000 with a resolution of 1024 by 768 pixels (ViALUX) was used, and the number of the active pixels was 768 by 768. The RGB images are combined using a trichoric prism and projected onto the inside of the ball lens through the dual-axis scanner and magnifying optics. The dual-axis scanner comprises two scanners and a high-NA scanning optics. The resonance scanner is driven at 240 Hz with \(\pm\)30-degree scanning angle and rotates an image around the horizontal axis. The galvanometer scanner is driven at 12 Hz with \(\pm\)40-degree scanning angle and rotates an image around the vertical axis. Although the resonance scanner has a high frequency, it is difficult to finely adjust the frequency. Therefore, we used the resonance scanner in conjunction with the galvanometer. The NI-6366, with a maximum sample rate of 2 MS/s and maximum update rate of 3.3 MS/s (National Instruments), was used to synchronize the scanners. The acceptance angle of the dual-axis scanner determined by the scanning optics was \(\pm\)22.1 degrees. The magnifying ratio of the magnifying optics relaying the image from the scanner to the ball lens was 1.33. The ball lens had a diameter of 150 mm. The specifications of each scanner and dual-axis scanner are listed in Table 2. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Surface** & **Radius** & **Thickness** & **Material** & **Semi-Dia.** \\ \hline Input distance & Infinity & 56 & & 25.0 \\ Convex 1 & \(-\)129.2 & 20 & N-BK7 & 62.5 \\  & Infinity & 1 & & 62.5 \\ \hline   Convex 1 & \(-\)129.2 & 20 & N-BK7 & 62.5 \\  & Infinity & 1 & & 62.5 \\ \hline   Convex 1 & \(-\)129.2 & 20 & N-BK7 & 62.5 \\  & Infinity & 1 & & 62.5 \\ \hline   Convex 2 & \(-\)103.5 & 17 & N-BK7 & 50.0 \\  & Infinity & 1 & & 50.0 \\ \hline   Convex 2 & \(-\)103.5 & 17 & N-BK7 & 50.0 \\  & Infinity & 1 & & 50.0 \\ \hline   Concave & 52.2 & 2 & N-BK7 & 25.0 \\  & \(-\)52.2 & 14.5 & & 25.0 \\ \hline   Convex 2 & Infinity & 17 & N-BK7 & 50.0 \\  & 103.5 & 1 & & 50.0 \\ \hline   Convex 2 & Infinity & 17 & N-BK7 & 50.0 \\  & 103.5 & 1 & & 50.0 \\ \hline   Convex 1 & Infinity & 20 & N-BK7 & 62.5 \\  & 129.2 & 1 & & 62.5 \\ \hline   Convex 1 & Infinity & 20 & N-BK7 & 62.5 \\  & 129.2 & 1 & & 62.5 \\ \hline   Convex 1 & Infinity & 20 & N-BK7 & 62.5 \\  & 129.2 & 1 & & 62.5 \\ \hline   Output distance & Infinity & 56 & & 25.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Lens parameters of the proposed scanning optics for the dual-axis scanner. Figure 13 presents the experimental results of the proposed full-parallax multiview images according to the viewing angle. The target object is a puzzle cube, and several view images are rendered at different angles--top, bottom, center, left, and right by 20 degrees, as shown in Figure 13a. Figure 13b shows the views captured by the cameras located at different angles. The camera positions are rotated 20 degrees up, down, left, and right from the center. The captured views are almost identical to the target images, as expected. However, some color dispersion appears in the left, right, top, and bottom views, as is evident from the side views. For example, in the left view, the red color shifts rightward, but in the right view, the red color shifts to leftward. The color dispersion appears because the region colored by the long wavelength shifts into the optical axis. Conversely, the region colored by the short wavelength shifts into the radial direction.