AIR-range: Designing optical systems to present a tall mid-AIR image with continuous luminance on and above a tabletop

Mid-air images in a three-dimensional space beyond a screen enable users to observe virtual content without wearing any devices. When using a symmetrical mirror structure with dual slit-mirror arrays, the system enables the display of a large mid-air image by integrating multiple imaging paths. However, in the mirror design used in previous research, the luminance was discontinuous. In this study, we propose a novel tabletop system in which a tall mid-air image with continuous luminance is superimposed onto physical objects. Our proposed system, called "AIR-range", presents mid-air images that appear seamlessly from the table surface to mid-air. By theorizing the relationship between the parameters of optical systems and luminance of mid-air images, we optimized the optical systems to minimize the difference in luminance between the imaging paths. The results of the comparison with the previous method showed an improvement in luminance continuity.