## 4 Experimental Results
For \"dinosaur\", the fine wrinkles and roughness of the skin observed in the ground truth were reproduced by the proposed system compared with the 3D images produced by the previous system. For \"globe\", the line patterns on the sphere surface were observed in the proposed system, and the map texture on the sphere surface observed in the proposed system was closer to that in the ground truth than in the images produced by the previous system. Figure 5: 3D images of the proposed system captured from different directions © UTJ/UCL. Figure 7 shows the magnified images of the \"globe\" produced by the proposed and previous systems to compare the blurs in each technique. The 3D images of the pillar of the globe, indicated by red squares in Figure 7, were displayed approximately 90 mm in front of the screen, and a larger blur occurred in the proposed system compared to that in the previous system. When the 3D images were displayed far from the screen plane, the ray  
Figure 6: Comparison of the 3D images displayed by the proposed and previous systems. divergence increased more rapidly in the proposed system than in the previous system, resulting in a larger blur in the proposed system, as discussed in Section 2. From Equation (5), the widths of the rays of the proposed and previous systems were 14.1 and 6.61 mm, respectively. As the divergence of rays at the depth of 90 mm was larger for the proposed system than for the previous one, the 3D image of the pillar presented by the proposed system was more blurred than that of the previous system, although the resolution was higher. In addition, Figure 7b shows the moire pattern because the commercially available lens array and liquid crystal display were employed for the prototype system. The brightness of the 3D images produced by the proposed and previous systems was 97.3 and 109 cd/m\({}^{2}\), respectively. The decrease in brightness can be explained by the width of the slits of the slit array. The ratios of the width to the pitch of the slits were 0.408 and 0.492 for the proposed and previous systems, respectively. In the present prototype system, we limited the virtual aperture width to be smaller than the lens pitch to prioritize the suppression of lens aberrations. The light efficiency of the proposed technique can be improved by widening the aperture width. The existence of black regions between the virtual slit images hindered the efficient increase in the resolution; hence, eliminating them is desirable to smoothly connect the virtual pixel images. To eliminate the black regions, the width of the virtual slit images should be equal to the lens pitch. However, this could not be achieved in the proposed system because a commercial lens array was used. A custom lens array should be designed and used to eliminate these black regions. The resolution of the 3D images generated using the previous system was 983 \(\times\) 720, although the aspect ratio of the display screen was 16:9. In this study, the horizontal resolution was doubled, resulting in an improvement in the balance of the horizontal and vertical pitches of the 3D pixels. An increase in the number of rays or viewpoints usually degrades the abovementioned balance. Therefore, the proposed technique can be used to improve the balance. In this study, we applied a prototype system that only had a horizontal parallax, and it doubled the horizontal resolution. The proposed technique can also be applied to a full-parallax light-field display. Improvements in both the vertical and horizontal resolutions can be achieved by using both the lens and aperture arrays. The vertical and horizontal resolutions are improved in \(n\)\(\times\)\(n\) times, as described in Section 2. However, the full-parallax system might have a lower resolution, narrower viewing zone angle, and wider ray divergence than the horizontal parallax system.